I

The National Ribat University.

College of Graduate Studies

and Scientific Research.

Study of the Placental Location in the Third

Trimester Using Ultrasound.

A Thesis Submitted in Partial Fulfilment of the

Requirements for the Degree of the M.Sc. in Medical

Diagnostic Ultrasound.

By

Khadra Abdulkadir Khalif

Supervisor:-

Dr. Elsir Ali Saeed

PhD in Medical Diagnostic Ultrasound

ھـ م - 1439 2018

I

Dedication

To my father, my mother, sisters, brothers, family and friends,

with love, respect, gratitude and appreciation.

I I

Acknowledgement

I would like to express my deep gratitude, indebtedness, respect

and profound thanks to my supervisor, Dr. Elsir Ali Saeed for

his support, invaluable comments, suggestions, keen

supervision, and constant encouragement, without which this

study could have not been in this form.

My special thanks due to Dr. Mohamed Elfa dil Mohamed

GarElnabi, for his appreciate orientation and valuable

guidance, who devoted a great deal of his precio us time

reading this dissertation.

My sincere thanks are also due to the administration and the

staff of Omdurman Maternal Hospital (Dayat Hospital), who

assisted me in obtaining the collection of this data. My special

thanks are due to my family who supported me morally and

materially throughout this study.

I am greatly indebted to the administration and the staff of

Afro-Asian Medical Training centre for their help during this

research.

I share any credit that might be accorded to this work with all

those who contributed to it. However, any shortcomings are

expressly mine.

I I I

Table of contents Title Page

Dedication ………………………………………………………... I

Acknowledgement ………………………………………………... II

Table of contents………………………………………………….. III

English Abstract…………………………………………………... V

Arabic Abstract …………………………………………………... VI

List of Figures……………………………………………………. VII

List of Tables …………………………………………………….. VIII

List of Abbreviations……………………………………………… IX

Chapter one………………………………………………………. 1

1.1.Introduction ………………………………………………......... 2

1.2. Statement of the Research Problem ……………………………. 3

1.3 .Objectives ………………………………………………… ….. 4

1.4.Organisation of the Research ………………………………….. 4

Chapter Two………………………………………………….. …... 5

Background and Literature Review………………………………… 6

2.1. placenta anatomy…………………………………………… 6

2.1.1. Development……………………………………………… 6

2.1.2. Structure…………………………………………………….. 8

2.1.3.Umbilical cord……………………………………… ……….. 9

2.1.4.Cord Insertion………………………………………… …… 9

2.2.1.5.Placental circulation……………………………………… 10

2.2. Physiology…………………………………………………… 13

2-3. Ultrasound Evaluation of placenta..................................... 14

2.3.1. Location…………………………………………………… 14

2..3.2 . placenta Echo Texture.................................................. 15

2.3-4. Retroplacental Uterine Wall................................................ 16

2-4.NormalVariants…………………………………………....... 17

2.5. Pathology of placenta………………………………………… 20

2.5.1.Placental infarction…………………………………............. 20

2.5.2 .Placental Causes of Antepartum Hemorrhage…….. ……… 20

2.5.3. Placental Abruption………………………………………. 20

IV

2.5.4. Placenta Previa…………………………………………….. 22

2.5.5. Vasa Previa…………………………………....................... 24

2.5.6. Placental Hematoma………………………………... …….. 25

2.5.7. Morbidly adherent placenta................................................ 26

2.5.8.Placental Tumours………………………………….............. 28

2.6. Previous studies……………………………………………… 28

Chapter Three……………………………………………………… 31

Methodology……………………………………………………... 32

3-1: Design of the Study…………………………………………... 32

3.2.Population of the Study………………………………………. 33

3.3.Data Collection…………………………………………………

32

3.4.Techniques utilized………………………….............................

33

3.5.Data Analysis………………………………. ………………

33

3.6.Ethical Approval……………………………. ……………….

33

4.Chapter Four.............................................................................

34

4.1.Results.....................................................................................

35

5.Chapter Five..............................................................................

44

5.1.Discussion...............................................................................

45

5.2.Conclusion...............................................................................

48

5-3.Recommendations...................................................................

49

References…………………………………………………………..

50

Appendices.................................................................................... 52

V

Abstract

Ultrasound is the best means to determine the location of

placenta and its proximity to the cervix. This descriptive

research is intended to assess the placental position in some

normal pregnant women in third trimester . This study was

conducted in Omdurman Maternal Hospital (known as Dayat

Hospital), from October to December 2017.

100 pregnant women in the Third Trimester were scanned by

ultrasound machine Toshiba-Power Vision-6000. The variables

used to set up this study were:-Mother Age, Mode of Delivery,

Hypertension, Diabetes, Number of Pregnancies, Fetal

Presentation, Gestational Age, Estimated Fetal Weight,

Amniotic Fluid Volumes and the Gravidity. Out of 100 pregnant

women, 56% were anterior, 42% were posterior and only 2%

were fundal. The ages between 25- 29 were the most frequencies

of pregnant women in the study. It is found that the pregnant

women who have hypertension were only 7% of the sample.

However, diabetes was only 6%. It is obse rved that only 2% of

pregnant women can have twins. Cephalic constitutes 92% o f the

sample, whereas breech comprises only 8%. According to the

estimated fetal weight, the most frequent weight was 3.1-3.5kg.

In short, it was observed that there is no correlation, between

the variables above mentioned and the placental location.

VI

خلاصة

يهدف هذا الموجات فوق الصوتية هي أفضل وسيلة لتحديد موقع المشيمة وقربها من عنق الرحم.

الحوامل العادية. أجريت هذه الدراسة النساءالمشيمة في بعض وضعلتصميم وتقييم وصفيالبحث ال

.2017في مستشفى أم درمان للولادة )المعروف باسم مستشفى الدايات(، من أكتوبر إلى ديسمبر

-الموجات فوق الصوتية توشيبا جهازالحوامل في الثلث الاخير من قبل النساء من مائة عددتم مسح

6000.

عمر الأم، طريقة الولادة، ارتفاع ضغط -:من كل المتغيرات المستخدمة لإعداد هذه الدراسة كانت

الدم، مرض السكري، عدد الحمل، عرض الجنين، عمر الحمل، وزن الجنين المقدر، كميات السائل

منهن ٪56الحوامل، كان النساءمن 100. ومن بين الحمل مرات عددالذي يحيط بالجنين و

النساء من 29و 25قاعي. وكانت الأعمار بين فقط منهن ٪ 2، و الخلفيمنهن ٪ 24، و الأمامي

ئي٪ من العينة. وتبين أن النساء الحوامل 37الحوامل في الدراسة، تشكل يعانون من ارتفاع اللا

من٪ فقط 2٪. ويلحظ أن 6٪ فقط من العينة. ومع ذلك، كان مرض السكري فقط 7ضغط الدم كانت

٪ من العينة، في حين 92نسبة رأسيال الجنين وضعتحملن التوائم. ويشكل الأمهات الحوامل كانتا

، الذي 3.5kg-3.1وفقا للوزن المقدر للجنين، كان الأكثر الوزن شيوعا .٪ فقط8 تشكلأن المؤخرة

.٪ من العينة32يشكل

وباختصار، لوحظ أنه لا يوجد ارتباط، بين المتغيرات المذكورة أعله وموقع المشيمة.

VII

List of Figures

Title Page

Figure 2.1 development of the placenta during the first 21 days of gestation 7

Figure 2.2 Normal Cord Insertion Sonogram of the uterus ………………… 10

Figure 2.3 Fetal and maternal circulation …………………………………... 12

Figure 2.4 Normal Early Placenta …………………………………………. 15

Figure 2.5 Normal Anterior Placenta ……………………………………… 16

Figure 2.6 Retroplacental Complex ……………………………………….. 17

Figure 2.7 Bilobed placenta. ………………………………………………. 18

Figure 2.8 Succenturiate placenta. ………………………………………… 18

Figure 2.9 Circumvallate placenta…………………………………………. 19

Figure 2.10 placenta membranacea. ………………………………………… 19

Figure 2.11 placental abruption……………………………………………… 21

Figure 2.12 placenta previa …………………………………………………. 23

Figure 2.13 vasa previa……………………………………………………… 25

Figure 2.14 subchorionic hematoma………………………………………… 26

Figure 2.15 Morbidly adherent placenta…………………………………….. 27

figure 4.1 Age and Placenta Location……………………………………… 35

figure 4.2 the Gravidity and Placenta Location………………………….. 36

figure 4.3 Mode of Delivery and Placenta Location………………………. 37

figure 4.4 Gestational Hypertension and Placenta Location……………… 38

figure 4.5 Gestational Diabets and Placenta Location ……………………. 39

figure 4.6 Number of Pregnancies and Placenta Location ………………… 40

figure 4.7 Fetal Presentation and the Placenta Location …………………. 41

figure 4.8 Estimated Fetal Weight and the Placenta Location…................... 42

figure 4.9 Amniotic Fluid Volume and the Placenta Location……………… 43

VIII

List of Tables

Title Page

figure 4.1 Age and the Placent Location……………………………………. 35

figure 4-2 The Gravidity and Placenta Location….…………………………

36

figure 4.3 Mode of Delivery and Placenta Location……………….………… 37

figure 4.4 Gestational Hypertension and the Placenta Location……………... 38

figure 4.5 Number of Pregnancies and the Placenta Location….…………… 39

figure 4.6 Fetal Presentation and the Placenta Location…………………… 40

figure 4.7 Gestational Age per Week and the Placenta Location…………… 41

figure 4.8 Estimated Fetal Weight and the Placenta Location……............... 42

figure 4.9 Amniotic Fluid Volume and the Placenta Location………………. 43

IX

List of Abbreviations

AFV Amniotic Fluid Volume

BPD Biparietal Diameter

C/S Caesarean Section

EFW/KG Estimated Fetal Weight per Kilogram

FL Femur Length

HC Head Circumference

KG Kilogram

MA Maternal Age

MVP Maximum Vertical Pocket

NSVD Normal Spontaneous Vaginal Delivery

SPSS Statistical Package for Social Science

WKS Weeks

US Ultrasound

1

Chapter One

2

Chapter One

Introduction

Placenta is an important connecting organ between mother and

fetus. classified high or low and anterior or posterior categories

if placenta implanted on the lower segment of the uterus is

called low lying placenta(1).

Both the American College of Obstetricians and Gynecologists

and the American Institute of Ultrasound in Medicine

recommended that the standard obstetric sonogram in the second

and/or third trimester should include the evaluation of placental

position and morphology, the estimation of amniotic fluid

volume, and the evaluation of both the morphology and function

of the umbilical cord( 2).

In most pregnancies, implantation occurs in the upper portion of

the fundus. It has been found that 37% of placentas attach

anteriorly, 24% posteriorly, and 34% in fundal position ( 3).

Placental position and morphology may change considerably

during pregnancy. If the area of implantation is less than optimal

for placental development, the placenta moves to a more suitable

region of the endometrium for adequate blood supply( 3).

Parts of the placenta located in less favourable positions atrophy

with time. For example, low implantation of the placenta occurs

frequently in early pregnancy, but this may change through

differential growth of the placenta and uterus( 3). The

relationship between placental morphology (placental width,

volume, and circumference), fetal development, and pregnancy -

related complications has been investigated previously ( 3).

3

However, the relationship between placental localisation, birth

weight, and Doppler parameters is less known. Lateral placenta

may predispose certain women to uteroplacental insufficiency

and low birth weight(3). Similarly, the blood supply of the

anterior and posterior parts of the uterus may differ, possibly

causing differences in birth weight and Doppler parameters (3).

While abnormalities in amniotic fluid volume and umbilical cord

Doppler velocimetry immediately alert the sonogra pher

(possible implications on the continuation of physiological

pregnancy), sonographic assessment of placental location , after

exclusion of previa or marginal insertion (necessary to assess

the option of vaginal delivery), is often limited to a mere

notional description without any link to possible implications on

pregnancy and childbirth ( 2).

There is a relative paucity of data regarding Placental Location.

Furthermore, studies of its association with specific obstetric

complications have reached contradictory conclusions and no

consensus has yet been achieved regarding the relationship

between Placental Location and non-vertex fetal presentation at

term(2).

1.1 Statement of the Research Problem:

The placenta is an organ connecting the developing fetus to the

uterine wall to allow nutrient uptake, waste elimination, and gas

exchange via the mother's blood supply(4).

Location of the placenta within the uterus is likely important

determinants of placental blood flow, fetal presentation, and

therefore pregnancy success . Thus, this study is intended in such

a way that it targets to study the different positions of placenta.

4

1.2.Objectives:

General objectives:-

To study the placental location in the third trimester using

ultrasound, in order to find the most prevalent placental

location.

Specific objectives:-

To find sites of Placental Location and its effect on fetal

presentation.

To find the effect of certain pregnancy complications on

Placental Location.

To find the effect of placental location on the estimated

fetal weight and the amniotic fluid volume.

1.3.Organisation of the Research

This research consists of five Chapters. Chapter one covers

the introduction which contains (Statement of the research

problem, Objective of the study, Research methodology and the

Organisation of the research). Chapter two explains literature

review which takes account of (Anatomy, Physiology, Pathology,

Sonographic appearance and Sonographic pathology of the

placenta location and previous studies relevant to this research).

Chapter three explore research methodology. Chapter four

discovers result and data analysis. And chapter five presents

discussion, conclusion and recommenda tions.

5

Chapter Two

6

Chapter Two

Background and Literature Review

2.1: placenta anatomy

2.1.1. Development:

The placenta is the organ responsible for providing endocrine secretions

and selective transfer of substances to and from the fetus. It serves as an

interface between the mother and developing fetus. Understanding the

development of the placenta is important, as it is the placental

trophoblasts that are critical for a successful pregnancy (5).

By day 3 or 4 after fertilization, the embryo consists of about 100 cells

and floats free in the uterus While the blastocyst floats in the uterine

cavity for two to three days, it is nourished by the glycogen -rich uterine

secretions. Then, some six to seven days after ovulation, given a

properly prepared endometrium, implantation begins (6).

When it implants into the maternal decidua and develops villous

projections for gaseous exchange and the transfer of nutrients from the

maternal circulation. At about 9weeks differentiates into the chorionic

leave (smooth) which becomes membranous fusing with the amnion

and chorion frondosum (frond-like) which becomes true placenta (7).

The invading trophoblast penetrates endometrial blood vessels forming

intertrophoblastic maternal blood-filled sinuses . Blood pools known

as lacunae that form as maternal capillaries erode nourish the

proliferating trophoblastic cells.

A primitive is formed, and the lacunae and trophoblastic cells develop

into a mature placental/maternal circulation complex that will sustain

the pregnancy(1 6) blood exchange network between mother and

conceptus

7

Trophoblastic cells advance as early or primitive villi, each consisting

of cytotrophoblast surrounded by the syncytium. Simultaneously, the

lacunar spaces become confluent with one another and, by weeks 3 –4,

form a multilocular receptacle lined by syncytium and filled with

maternal blood: this becomes the future intervillous space. With

further growth of the embryo the decidua capsularis becomes thinner,

and both villi and the lacunar spaces in the decidua are obliterated,

converting the chorion into chorion ic levae. The villi in the chorionic

frondosum show exuberant division and subdivision, and with the

accompanying proliferation of the deciduas basalis, the future placenta

is formed. This process starts at 6wks and the definitive numbers of

stem villi are established by 12wks (5).

Fig 2.1: Diagrammatic representation of the development of the placenta

during the first 21 days of gestation (8).

Placental growth continues to term. Until week 16, the placenta grows

both in thickness and circumference due to growth of the chorionic villi

with accompanying expansion of the intervillous space. After 16wks

growth occurs mainly circumferentially (1 7).

2.1.2: Structure:

Typically, at term placenta weighs nearly a pound (500g), 20cm to 22cm

long and is 2cm to 2.5cm thick. It is dark maroon in colour in the

8

maternal side and shiny translucent gray in colour in foetal side. It is

attached to the foetus by the umbilical cord. (2 1).

Occupies 30% of the uterine wall at term and has two surfaces:

Fetal surface: Covered by a smooth, glistening amnion with the

umbilical cord usually attached at or near its centre. Branches of the

umbilical blood vessels are visible beneath amnion as they radiate from

the insertion of the cord(5).

Maternal surface: Rough and spongy appearance, divided into bumps

cotyledons (15–20) by septa arising from the maternal tissues. Each

cotyledon may be supplied by its own spiral artery. Numerous small

greyish spots may be visible on the maternal surface representing

calcium deposition in degenerated areas (5). The placental membranes

are composed of the amnion and chorion. The amnion is first

identifiable about the seventh or eighth day of embryonic development

and eventually engulfs the growing embryo. As the pregnancy

progresses the amnion is brought into contact with the chorion. This

occurs at approximately twelve to fifteen weeks gestation. The placental

parenchyma is composed of a stromal compartment that is filled with

vascular and lymphatic channels. The stroma eventually becomes

slightly elevated with convex areas called lobes which are incompletely

separated by grooves. The number of lobes varies from 10 to 38 and the

number remains the same throughout gestation (1 3).

9

2.1.3:Umbilical cord

Umbilical cord is usually 1 to 2cm in diameter and the length of

the cord Varies from 30 to 90cm recent study by Bulkawade et al

suggested that the length may vary 24 to 124cm normally (1 4)

Vascular cable that connects the fetus to the placenta covered by

amniotic epithelium contains two umbilical arteries and one umbilical

vein embedded into the Wharton’s jelly.

Arteries carry deoxygenated blood from fetus to placenta and the

oxygenated blood returns to fetus via the umbilical vein. In a full -term

fetus, blood flow in the cord approximate ly is 350mL/min (5).

2.1.4: Cord Insertion:

The placental cord insertion site should be sought and documented.

According to the literature, the placental cord insertion site may be

visualized with real -time ultrasound between 50-60% of pregnancies in

routine clinical practice and over 95% of cases w ith colour Doppler (9).

The placental cord insertion site is most difficult to assess when the

placenta is posterior and in the presence of oligohydramnios. The

umbilical cord normally inserts near the center of the placenta.

A cord which appears to insert near the edge of the placenta is called a

marginal insertion or battledore placenta and is generally thought to be

of no concern (9).

A cord which fails to reach the placenta and inserts in the membranes is

known as a velamentous insertion and may complicate the pregnancy

especially if the intramembranous umbilical vessels are close to or cross

the internal os (a condition known as vasa previa) (9).

10

Fig:2.2 Normal Cord Insertion Sonogram of the uterus shows a

posterior placenta with a central umbilical cord insertion ( 9).

2.1.5:Placental circulation

The placental circulation brings into close relationship two circulation

systemes the maternal and the fetal. The supply of blood to the placenta

is influenced by various factors, especially by the arterial blood

pressure, uterine contractions, tobacco abuse, medications and

hormones. Placental blood flow is increased at term and amounts to 500

ml/min (80% of the uterine perfusion). (1 5).

Uteroplacental circulation is the maternal blood circulating through the

intervillous space . Intervillous blood flow at term is estimated to be

500–600mL/min, and blood in the intervillous space is replaced 3 –4

times/min. Pressure and concentration gradients between fe tal

capillaries and intervillous space favours placental transfer of oxygen

and other nutrients to the fetus (5). Spiral arteries respond to the increase

demand of blood supply to the placental bed by becoming low -pressure,

high-flow vessels.

11

They become tortuous, dilated, and less elastic by trophoblastic

invasion, which starts early in pregnancy and occurs in two stages, in

first trimester, the decidual segments of the spiral arterioles are

structurally modified,in second trimester, second wave of troph oblastic

invasion occurs, resulting in invasion of myometrial segments of spiral

arteries. Failure of this physiological change, particularly second wave

of trophoblastic invasion, is implicated in development of preeclampsia

and intrauterine growth restri ction (5).

Blood entering the intervillous space from the spiral artery becomes

dispersed to reach the chorionic plate and gradually the basal plate,

being facilitated by mild movements of villi and uterine contractions

(1 7).

From basal plate, uterine veins drain the deoxygenated blood. Venous

drainage only occurs during uterine relaxation (5). Spiral arteries are

perpendicular and veins are parallel to uterine wall, making large

volumes of blood available for exchange at the intervillous space even

though the rate of flow is decreased during contraction, i.e. the veins

are blocked for a longer time to allow pooling of blood in the

retroplacental area (5).

Two umbilical arteries carry deoxygenated blood from the fetus and

enter the chorionic plate underneath the amnion (5). Arteries divide into

small branches and enter the stem of the chorionic villi, where further

division to arterioles and capillaries occurs (5). The blood then flows to

the corresponding venous channel and subsequently to the umbilical

vein. Maternal and fetal bloodstreams flow side by side, in opposite

directions, facilitating exchange between mother and fetus (5).

Oxygenated and nutrient -rich fetal blood passes from the fetal capillary

bed in the villi to an enlarging system of veins that eventually converge

to form a single umbilical vein in the umbilical cord(9).

12

In the fetal abdomen, the umbilical vein courses cranially towards the

liver where it joins the portal sinus (umbilical portion of the left portal

vein) to supply the liver.

Most of the fetal blood bypasses the liver via the ductus venosus which

originates at the portal sinus and terminates in the inferior vena cava or

left hepatic vein (9). Deoxygenated blood returns from the fetus to the

placenta via two umbilical arteries which originate at the right and left

internal iliac arteries in the fetal pelvis. The two umbilical arteries

divide into numerous radiating branches as the cord inserts in the

placenta (9).

Fig 2.3: Fetal and maternal circulation (9).

13

2.2: Physiology

The placenta receives and transmits endocrine signals between the

mother and fetus and is the site of nutrient and waste exchange. The

total placental surface area for exchange is 11 m 2 at term. (1 8).

The placenta is a metabolically active organ and manages to extract 40 –

60% of the total glucose and oxygen supplied by the uterine circulation.

Various nutrients and metabolites are transferred across the placenta to

the fetus by passive diffusion (oxygen,carbon dioxide, urea, fatty acids),

facilitated diffusion(glucose, lactate), active transport (amino acids,

fatty acids), as well as endocytosis or exocytosis (8).Facilitated diffusion

involves transfer down a concentration gradient by a carrier molecule

without the requirement of additional energy. Active transport, in

contrast, requires both carrier proteins and additional energy. In

general, placental transfer increases throughout gestation as the fetal

growth rate increases (8).

As an active endocrine organ, the placen ta produces a number of

hormones, growth factors, and cytokines. The production of human

chorionic gonadotrophin (hCG), oestrogens, and progesterone by the

placenta is vital for the maintenance of pregnancy (8).The placenta acts

as a barrier for the fetus against pathogens and the maternal immune

system(5).

The placenta forms an effective barrier against most maternal blood -

borne bacterial infections. However, some important organisms, such as

syphilis, parvovirus, hepatitis B and C, rubella, human immune

deficiency virus (HIV), and cytomegalovirus (CMV) are able to cross it

and infect the fetus during pregnancy(5).

Many drugs administered to the mother will pass across the placenta

into the fetus; exceptions include low-molecular-weight heparin

(LMWH).

14

Some drugs may have little effect on the fetus and be considered ‘safe’

(e.g. paracetamol), but others (e.g. warfarin) may significantly affect

development, structure, and function of the fetus —a process known as

teratogenesis (5).

2-3: Ultrasound Evaluation of placenta

Ultrasonography is the preferred technique for placental localization. It

permits a comparatively precise estimate of the separation of the lower

placental margin and internal cervical os (12).

.General evaluation of the placenta sh ould be a routine part of every

second and third trimester ultrasound study as indicated in the American

Institute of Ultrasound in Medicine Antepartum Obstetrical Ultrasound

Examination Guidelines ("The placental location, appearance, and its

relationship to the internal cervical os should be recorded") (9).

Routine evaluation of the placenta with colour Doppler is now favoured

to rapidly find the placental cord insertion site and to detect vascular

abnormalities in the placenta and the retroplacental uterine wall (9).

This is especially important if the placenta is anterior and appears to be

low-lying or previa since the risk of placenta acreta is highest in this

situation. An important view is the median lower segment and cervix

image which may ident ify vasa previa associated with velamentous

insertion of the cord or succenturiate lobe (9).

2.3.1: Location:

The reliability of ultrasonographic localization of the placental site has

been tested in many different ways (1 9). The placenta may be described

as predominantly anterior, posterior, fundal, right or left lateral. A

placenta that is distant from the internal os may be described as being in

a normal location, central, or non previa (9).

15

A low-lying placenta describes a placenta which appears to exten d into

the lower uterine segment and is within 1 -2 cm of the internal os. A

placenta previa describes a placenta which appears to partly or

completely cover the internalos. Documentation should include an image

showing placental location and the relationsh ip to the internal os (9).

Fig.2.4 :Normal Early Placenta Longitudinal TAS image of the uterus (bladder is

empty) shows a normal anterior placenta (1) and a retro placental FMC.

2.3.2: placenta Echo Texture

The normal placenta appears as a sonographically uniform structure

with mid amplitude echoes (in contrast, the adjacent uterine wall

(decidua and myometrium) appear less echogenic or hypoechoic). In the

third trimester, the placenta generally appears less homogeneous and

may have small anechoic or hypoechoic areas of different pathological

etiologies. Calcium deposits are seen in the majority of placentas in the

third trimester and appear as high amplitude (white) linear echoes (9).

16

Fig.2.5 : Normal Anterior Placenta TAS image at 19 weeks gestation shows a

normal anterior placenta extending into the lower segment of the uterus. Note the

normal hypoechoic uterine wall sandwiched between the placenta and the bladder

wall .

2-3-4: Retroplacental Uterine Wall

The retroplacental uterine wall consists of the richly vascular

myometrium and decidua basalis. These tissues are distinctly

hypoechoic in comparison to the placenta (9). After 18 weeks gestation,

the normal anterior retroplacental uterine wall (sometimes referred to as

the subplacental complex or the retroplacental space) has an average

thickness of 9.5 mm(. The sonographic diagnosis of placental creta

depends on this normal hypoechoic zone being invaded by more

echogenic villi and appearing thinner or not seen. The endometr ial veins

in the decidua basalis may be quite dilated and appear as irregular,

tubular spaces especially when the placenta is posterior (probably due to

diminished venous drainage when the patient is supine and the weight of

the uterus on the posterior ute rine wall impedes venous flow)(9).

Other retroplacental abnormalities include hematomas associated with

abruption of the placenta and fibroids which must be distinguished from

focal myometrial contractions (9).

17

Fig2.6 Retroplacental Complex Sagit tal TAS image of a posterior placenta (1)

shows a prominent retroplacental complex and the "end" of a FMC(3). ( 9).

2-4: Normal Variants

Typically, the placenta is located along the anterior or posterior

uterine wall, extending into the lateral walls. Although usually

discoid, the placenta can be variable in morphology. Variant

placental shapes include: bilobed is a Placenta with two

relatively even sized lobes connected by a thin bridge of

placental tissue, succenturiate An additional lobule separate

from the main bulk of the placenta , circumvallate Chorionic

plate smaller than the basal plate with associated rolled

placental edges, and placenta membranacea Thin membranous

structure circumferentially occupying the entire periphery of the

chorion (10).

18

Fig.2.7: Bilobed placenta. (a) Diagram shows a bilobed placenta. (b) US

image shows a bilobed placenta. The two lobes of the placenta ( P1 and

P2) are separated by a thin bridge of placental t issue that covers the

internal os. In this case, the umbilical cord (arrowhead) inserts into the

bridge of t issue (1 0) .

Fig.2.8: Succenturiate placenta. (a) Diagram shows a placenta with a

succenturiate lobe. (b) US image shows aplacenta (P) with a succenturiate lobe

(S) . The main body of the placenta is located along the posterior uterine wall . A

second soft -t issue st ructure of the same echogenicity but located anteriorly is the

succenturiate lobe(1 0).

19

Fig.2.9: Circumval late placenta. (a) Diagram shows a ci rcumvallate

placenta. (b) US image shows a ci rcumvallate placenta. The chorionic

plate (the fetal surface of the placenta) (black arrowheads) is smaller

than the basal plate (the surface interfacing with the uterus), with roll ing

and shouldering of the placental margins (white arrowheads). F =

fetus(1 0).

Fig.2.10 (a) Diagram shows a placenta membranacea. (b) Velamentous

insert ion of the umbilical cord. Doppler US image shows insert ion (I)

(white arrow) of the umbilical cord into a thin membrane of t issue

extending from the margin (black arrow) of the place nta (P) (1 0).

20

2.5: Pathology of placenta

2.5.1:Placental infarction

A placental infarction refers to a localised area of ischaemic

villous necrosis. It is a significant cause of placental

insufficiency. A localized infarction can occurs in up to 12.5%

(range 5-20%) of all gestations. It usually results from an

interrupted maternal blood supply (11). Placental infarcts are

more common at periphery of placenta. Most placental infarcts

are difficult to diagnose on ultrasound (11). They may on

occasion be seen as a hypoechoic region with thick hyperechoic

rim (11).

2.5.2 :Placental Causes of Antepartum Hemorrhage

Sonographically, placental hematomas may be difficult to distinguish

from subchorionic hemorrhages. Placental hematomas do not cause

symptoms, bleeding, or spotting because they are within the chorionic

sac and have no communication with the endometrium (11)

Antepartum hemorrhage (vaginal bleeding between 20 weeks

gestation and delivery) remains an important cause of maternal

and fetal morbidity and mortality.

Placenta previa and placental abruption account for more than

one half of cases of antepartum hemorrhage and a re increasing

in prevalence as the rate of cesarean section increases (1 0).

2.5.3 Placental Abruption

Placental abruption represents premature separation of the

placenta from the uterine wall. Although rare (<1% of

pregnancies), third-trimester abruption is associated with an

increased risk of preterm delivery and fetal death (1 0).

21

US is frequently performed to confirm the presence of abruption

and assess the extent of subchorionic or retroplacental

hematoma. The presence of blood in large enough volumes to be

visible sonographically indicates retained hemorrhage that may

remain symptomatic (1 0).

False-negative results can occur when blood dissects out from

beneath the placenta and drains through the cervix (10).

Fig 2.11:US image shows placental abruption. A crescenteric collection

of predominantly hypoechoic fluid l i fts the edge of the placenta (P) away

from the underlying myometrium (M) .

The fluid collection contains layering high -attenuation material

(arrowhead), a finding consistent with blood (1 0).

2.5.4 Placenta Previa

Placenta previa refers to abnormal implantation of the placenta

in the lower uterine segment, overlying or near the internal

cervical os. Normally, the lower placental edge should be at

least 2 cm from the margin of the internal cervical os (1 0).

The relationship of the placenta to the internal os changes

throughout the course of pregnancy as the uterus enlarges (1 0).

22

The prevalence has been estimated to be approximately 0.5% of

all pregnancies(11).It is a major cause of antepartum and

intrapartum hemorrhage; maternal morbidity and mortality ;

preterm delivery and neonatal mortality( 5).

Placenta previa is associated with a number of risk factors,

including: previous placenta previa, previous caesarean section,

old maternal age, multiparity, large placentas (11).

It is divided into 4 grades depending on the relationship and

distance to the internal os (11).

grade I - low lying placenta - placenta lies in lower uterine

segment but its lower edge does not reach up -to internal cervical

os (11).

grade II - marginal previa - placental tissue reaches the margin

of the internal cervical os, but does not cover it (11).

grade III - partial previa - placenta partially covers the internal

cervical os(11) .

grade IV - complete previa - placenta completely covers the

internal cervical os(11).

Sometimes types I and II are termed a minor or partial placenta

previa and types III and IV termed a major placenta previa (11).The

diagnosis of placenta previa should not be made before 15 weeks

gestation, and low-lying or marginal placental positioning should be

reevaluated later in gestation to confirm placental position before

delivery(1 0).Although transvaginal sonography is the imaging

standard for making this diagnosis, the position of the placenta is

usually demonstrable with transabdominal imaging (1 0).Transvaginal

or translabial approaches may be required to accurately demonstrate

the location of the placenta, particularly in posteriorly locat ed

placentas .

23

However, transvaginal imaging should be undertaken with care in

advanced pregnancies, as it can lead to premature rupture of

membranes or to infection when the membranes have already

ruptured(1 0).

Fig. 2.12: : Spectrum of placenta previa Transvaginal US image shows in

(a) : a low-lying placenta , (b): The placental margin comes to the

internal cervical os but does not cover i t , (c): The placenta entirely

covers the internal cervical os, (d): the posterior placenta ent irely covers

the internal cervical os(11).

24

2.5.5: Vasa Previa

Vasa previa refers to the presence of abnormal fetal vessels

within the amniotic membranes that cross the internal cervical

os. These vessels are unsupported by Wharton jelly or placental

tissue and are at risk of rupture when the supporting membranes

rupture; such vessels are also at risk of direct injury during

labor. Rupture of these vessels can lead to catastrophic fetal

hemorrhage (1 0).

In cases of vasa previa, the abnormal vessels either connect a

velamentous cord insertion with the main body of the placenta

or connect portions of a bilobed placenta or a placenta with a

succenturiate lobe . Given this association, vasa prev ia needs to

be excluded in patients with variant placental morphology. The

diagnosis of vasa previa is made with Doppler US, which

demonstrates vascular flow within vessels overlying the internal

cervical os (1 0).Occasionally, transvaginal US is required to

confirm the presence of these aberrant vessels. Marginal sinus

previa, where prominent maternal vessels are appreciated at the

edge of the placenta, can mimic vasa previa at color flow

imaging. As with placenta previa, patients with vasa previa

diagnosed in the second trimester should be reevaluated later in

gestation. The vasa previa can resolve as the uterus enlarges and

the relationship of the placenta to the internal os changes (1 0).

25

Fig2.13 :Transvaginal power Doppler US image obtained at 18 weeks

gestation shows an anterior placenta (P) . There is vascular flow in a

vessel (V) that is closely applied to the internal cervical os (O) . Follow-

up US at 32 weeks gestation showed resolution of the vasa previa, t hus

allowing subsequent uneventful vaginal delivery (1 0).

2.5.6: Placental Hematoma

Placental hematomas can occur on the fetal (preplacental or

subchorionic) side or maternal (retroplacental) side or be

centered within the placenta. At US, placental hemato mas

appear as well-circumscribed masses with echogenicity that

varies according to chronicity (1 0). They are hypoechoic or

anechoic in the acute phase, heterogeneously echogenic in the

subacute phase, and anechoic in the chronic phase. Doppler

interrogation should reveal absence of internal blood flow; this

finding allows differentiation of hematomas from other placental

masses(1 0).

26

Fig2.14: image shows a rounded collection of mixed -echogenicity

material (arrowheads) deep to the chorion along the lateral margin of the

placenta. There is no internal Doppler s ignal tosuggest blood flow. This

appearance is consis tent with a subchorionic hematoma(1 0).

2.5.7 Morbidly adherent placenta

During the process of placental development and implantation, a

defect in the normal deciduas basalis from prior surgery or

instrumentation allows abnormal adherence or penetration of the

chorionic villi to or into the uterine wall (1 0). The extent of

adherence to and invasion of the placental tissue varies:

Superficial invasion of the basalis layer is te rmed placenta

accreta (approximately75% of cases); deeper invasion of the

myometrium is termed placenta increta; and even deeper

invasion involving the serosa or adjacent pelvic organs is termed

placenta percreta (1 0) . This abnormal adherence of the placenta

to the uterus can result in catastrophic intrapartum hemorrhage

at the time of placental delivery, often necessitating emergent

hysterectomy (1 0).

27

Gray-scale US and Doppler imaging have been shown to be

effective imaging strategies for the detection of placenta accreta

when applied to a clinically high -risk population, such as those

with prior uterine surgery or placenta previa (1 0). Sonographic

features of placenta accreta include loss of the normal

retroplacental clear space, anomalies of the bladder -myometrium

interface, prominent placental lacunae, and increased vascularity

at the interface of the uterus and bladder (10). Of these various

sonographic features, the presence of prominent placental

lacunae has the highest positive predictive value (. Lacunae are

characterized by ill -defined margins, irregular shape, and

turbulent flow (1 0).

Fig.2.15 :US images show disruption of the normal hypoechoic

myometrium (black arrowheads) by invading placental t issue (white

arrowheads). B = bladder, P = placenta(1 0).

28

2.5.8 Placental Tumours

Non trophoblastic placental tumors are quite rare.

Chorioangiomas are the most common, occurring in less than 1%

of pregnancies . Placental teratomas are extremely rare and are

similar in appearance to chorioangiomas, but are differentiated

by the presence of calcifications .Melanoma is reported to be the

most common tumour to metastasize to the placenta (10).

2.6 Previous studies:

Gizzo et al.International Journal of Clinical and Experimental

Medecine (2015). Assessed sonography of placental location: a

mere notional description or an important key to improve both

pregnancy and perinatal obstetrical care? A large cohort study .

“We conducted an observational -prospective-cohort study on

pregnant women referred to the Ob/Gyn Unit of Padua

University for routine third-trimester ultrasound scan. For all

eligible patients we evaluated the correlation between sites of

PL and perinatal maternal/fetal outcomes. Non-cephalic

presentation was found in 1.4% of anterior, 8.9% of posterior,

6.2% of fundal and 7.2% of lateral insertions. FP at the

beginning of the third trimester as opposed to presentation at

birth was concordant in 90.3% of anteri or, 63.3% of posterior

and 76.5% of lateral insertions. Considering only non -cephalic

fetuses we observed a decreasing probability for spontaneous

rotation in the following lies: 88% anterior -PL, 80% posterior-

PL, 77% lateral-PL, and 70% fundal-PL. Patients with posterior-

PL (significantly associated with previous -CS) had a

significantly higher CS-rate (due to previous-CS and breech-

presentation).

29

Significant differences were found in terms of gestational -

hypertension and fresh-placental-weight between different sites

of PL. In conclusion our data showed that an understanding of

the role that PL plays in influencing the incidence of certain

maternal-fetal conditions may assist Clinicians in improving

perinatal maternal/fetal outcomes” . (2)

Ozoko et al. Ultrasonographic Study of Placenta Positioning and

Its Significance in Parturition among Women in Delta (2014)

“Ultrasound is a useful adjunct to the physical examination,

particularly in obstetrics patients. By ultrasonography we

visualize the placenta position in -situ and describe various

positioning of placenta in the uterus. The placenta is positioned

at different sites in the uterus which can predict methods of

parturition. The objective of this study is to investigate the

different positions of placenta as seen in ultrasound scan and it’s

significant in parturition among women in Delta state. The study

comprises of 150 women who registered for antenatal care at

Eku Baptist Hospital Eku, Delta state, and have given birth in

the Hospital. The pregnant women were examined with

ultrasound scan which determined the positions of the placenta

at the radio diagnostic department. The different positions such

as anterior, posterior, fundal and previa were recorded. The

methods of deliveries were also taken note of in the pre -

maternal labour forms in obstetrics/gynaecology department and

health record office of the Hospital.

Data were presented as mean and standard deviation; data were

analysed using statistical package for social scie nce (SPSS).

30

The cases of previa were related to the type of delivery out of 28

cases of previa 18 women delivered by caesarean section and 10

had normal delivery. 10 out of all are previa type I, 7 are previa

type II, and 11 are previa type III. All type III cases delivered

through caesarean section” . (2 0)

31

Chapter Three

32

Chapter Three

Methodology

3-1: Design of the Study

This research is a descriptive cross-sectional study about the normal

position of the placental location using ultrasound.

3-2: Population of the Study.

One hundred pregnant women have been examined by utilizing

ultrasound scan.

Pregnant women with gestational period of the Third Trimester are

included.

This research was preceded at Omdurman Maternal Hospital.

This study was conducted in a period of three months – from October

up to December 2017.

3-3: Method of Data Collection.

The data of this research was collected by using special data

collection sheet, which consists of ten variables like: - mother age,

number of featus in pregnancy, gestational age, mode of delivery,

gestational hypertension, gravidity, gestational diabetes, fetal

presentation, estimated fetal weight and amniotic fluid volume.

The research data collected from: -

- Routine referred pregnant women in the third trimester.

- Text books

- Websites

- Data collection sheet .

33

3-4: Techniques utilized .

In general, there was no special preparation like breathing technique

or full Bladder needed. Pregnant mother ought to be in supine

position; transabdominal convex transducer was used with frequency

of 3.5 MHz and ultrasound gel. During the ultrasound examination

FL, BPD, abdomen circumference (AC) and the placental location

were assessed in longitudinal section at the point of umbilical cord

insertion to display the placental site properly.

3-5: Data Analysis.

The data of this study was illustrated by figures and tables using

Excel Data Analyses and interpreted by SPSS system.

3-6: Ethical Approval.

Written permission taken from the administration of the research

department at the Omdurman Maternal Hospital.

No patient details were disclosed.

34

Chapter Four

35

Chapter Four

Results

Table 4-1: Cross-Tabulation of Age and Placenta Location.

Age Anterior Posterior Fundal Total

15 - 19 4 4 0 8

20- 24 10 8 0 18

25-29 20 17 0 37

30- 34 10 9 1 20

35-39 11 3 1 15

40-44 1 1 0 2

Total 56 42 2 100

Figure 4-1: Cross-Tabulation of Age and Placenta Location.

0

5

10

15

20

25

15-19 20-24 25-29 30-34 35-39 40-44

Anterior

Posterior

Fundal

36

Table 4-2: Cross-Tabulation of the Gravidity and Placenta Location.

Gravida Anterior Posterior Fundal Total

1 upto 2 25 15 0 40

3 upto 4 17 17 0 34

5 upto 6 6 7 1 14

7 upto 8 4 1 1 6

9 upto 10 4 2 0 6

Total 56 42 2 100

Figure 4-2: Cross-Tabulation of Gravidity and Placenta Location.

0

5

10

15

20

25

30

1 −2 3 −4 5 −6 7 −8 9 −10

Anterior

Posterior

Fundal

37

Table 4-3: Cross-Tabulation of the Mode of Delivery and Placenta

Location.

Mode of Delivery Anterior posterior Fundal total

C/S 18 15 0 33

NSVD 20 16 1 37

PRIMIGRAVIDA 17 12 1 30

TOTAL 55 43 2 100

Figure 4-3: Cross-Tabulation of the Mode of Delivery and Placenta

Location.

0

5

10

15

20

25

Anterior posterior Fundal

C/S

NSVD

PRIMIGRAVIDA

38

Table 4-4: Cross-Tabulation of Gestational Hypertension and Placenta

Location.

Hypertension Anterior Posterior Fundal Total

Hypertensive 3 4 0 7

Non Hypertensive 53 38 2 93

Total 56 42 2 100

Figure4-4: Cross-Tabulation of Gestational Hypertension and Placenta

Location.

0

10

20

30

40

50

60

Anterior Posterior Fundal

Hypertention

Non-Hypertention

39

Table 4-5: Cross-Tabulation of Gestational Diabetes and Placenta

Location.

Diabetes Anterior Posterior Fundal Total

Diabetic 4 2 0 6

Non-Diabetic 52 40 2 94

Total 56 42 2 100

Figure 4-5: Cross-Tabulation of Gestational Diabetes and Placenta

Location.

0

10

20

30

40

50

60

Anterior Posterior

Diabetic

Non-Diabetic

40

Table 4-6: Cross-Tabulation of the Number of Pregnancies and Placenta

Location.

Situation Anterior Posterior Fundal Total

Single 56 40 2 98

Twins 0 2 0 2

Total 56 42 2 100

Figure 4-6: Cross-Tabulation of the Number of Pregnancies and

Placenta Location.

0

10

20

30

40

50

60

Anterior Posterior Fundal

Single

Twins

41

Table 4-7: Cross-Tabulation of the Fetal Presentation and the Placenta

Location.

Featal Presentaion Anterior Posterior Fundal Total

Cephalic 51 39 2 92

Breech 5 3 0 8

TOTAL 56 42 2 100

Figure 4-7: Cross-Tabulation of the Fetal Presentation and the Placenta

Location.

0

10

20

30

40

50

60

Anterior Posterior Fundal

Cephalic

Breech

42

Table 4-8 Cross-Tabulation of Estimated Fetal Weight and The Placenta

Location in the GA of 35 Wks.

EFW/kg Anterior Posterior Fundal Total

2.1 - 2.5kg 4 1 1 6

2.6 - 3.0kg 1 1 1 3

3.1 - 3.5kg 1 1 2

3.6 - 4.0kg 1 1

Total 7 3 2 12

Figure 4-8 Cross-Tabulation of Estimated Fetal Weight and The

Placenta Location in the GA of 35 Wks.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

2.1 - 2.5kg 2.6 - 3.0kg 3.1 - 3.5kg 3.6 - 4.0kg

Anteriro

Posterior

Fundal

43

Table 4-9: Cross-Tabulation of the Amniotic Fluid Volume and the

Placenta Location.

TYPE Anterior Posterior Fundal Total

Average 54 41 2 97

Oligohydramnios 2 0 0 2

Polyhydramnios 0 1 0 1

TOTAL 56 42 2 100

Figure 4-9: Cross-Tabulation of the Amniotic Fluid Volume and the

Placenta Location.

0

10

20

30

40

50

60

Anterior Posterior Fundal

Average

Oligohydramnios

Polyhydramnios

44

Chapter Five

45

Chapter Five

Discussion, conclusion and recommendations

5-1. Discussion

The placenta is considered as a fetal organ. It presents an

indirect relationship between the maternal distribution and

that of the fetus and serves as the organ for exchange of

nutrients, gases and waste products through diffusion.

Ultrasonography is the ideal technique for placental

locataion.

The main objective of this research is intended to highlight

the placenta location for the pregnant mother in the third

trimester. It comprehended one hundred pregnant mothers

whose average ages were 28.52±6.17 years of anterior,

27.24±5.73 years of posterior and 34.50±3.53 of fundal, this

age constitutes 37% of the sample (table 4 -1 and figure 4-

1). The result showed that the primigravida and

secundigravida comprise 40% of the study, at 25% of

anterior and 15% of posterior (table 4-2 and figure 4-2). It

was observed during the study that the averages of placenta

location were: 18.33±1.53 of anterior, 14.33±2.08 of

posterior and 0.67±0.58 of fundal localization as illustrated

all the tables. According to the mode of delivery it was

noted that the averages were: - 11±9.64, 12.33±10.02 and

10±8.18 c/s, nsvd and Primigravida respectively (Table4 -3

and the figure 4-3).

46

The pregnant mothers who had hypertension formed only

7% of the sample, 3% of anterior and 4% of posterior (table

4-4 and figure 4-4).

And the mothers who have had diabetes constituted only 6%

of the sample study 4% of anterior and 2% of posterior

(table 4-5 and figure 4-5).

During the research period it was noted that the 38wks

were the most frequent week, which constitute 20% of the

sample size (table 4-8 and figure 4-8). It was also spotted

that the fetal presentation was 92% of cephalic and only 8%

of breech. The most weights seen during this study were

3.1-3.5kg, which compose 32% of the population studied

(table 4-9 and figure 4-9).Amniotic fluid volume was

dividedas 32.33±27.06 average, 0.67±1.16 , oligohydramnios

and0.33±0.57 polihydramnios(table 4 -10 and figure 4-10).

Gizzo et al.International Journal of Clinical and

Experimental Medecine (2015). observed that Cephalic

constitute 88% of anterior, 80% of posterior and70% of

fundal. While the current study showed that cephalic

represent 51% of anterior,39% of posterior and 2% of fundal

PL. But the current study observed that there is no any

association between previous c/s and Placenta location. This

data that breech constitute 5% of Anterior, 3% of posterior

and no fundal seen, whereas the previous showed that the

breech constititute 1.4& of Ante rior, 8.9% of posterior and

6.2% of fundal. (2)

47

Ozoko, et al .Ultrasonographic Study of Placenta Positioning

and Its Significance in Parturition among Women in Delta

State, Nigeria (2014). Analaysed the different positions

such as anterior, posterior, fundal and previa, but the previa

does not include in the current study. (2 0)

48

5-2. Conclusion

In this research covered 100 pregnant mother in the third

trimester, the most placenta 56% located in anterior, while 42%

located in posterior and only 2% located in fundal. During the

study, it was observed that the most ages 37% were the group

ages between 25-29yrs. Another prospect of this study was that

the fetal weights were found to be highest in cases of anterior

placentation, while lowest in cases of fundal placentation. Most

of the AFV 97% was normal-average; only 2% were

oligohydramnios of anterior, while only 1% was polihydramnios

of posterior placentation. In terms of gestational age the week

38 was the most weeks seen composing 20% of the sample size,

9% of anterior and 11% of posterior placental location. For the

fetal presentation, the cephalic constitutes 92%, 51% of it was

anterior, 39% of it was posterior and only 2% was fundal

placentation, whereas breech composes 8% of the sample, 5% of

it was anterior, and 3% was posterior. With regard to the

previous delivery status, it was seen that t he 33% was C/S, 37%

was NSVD and 30% was primigravidity. Regarding to the

number of pregnancies, it was seen that the only 2% was twins

at posterior placentation , and 98% was single, dividing into

56% of anterior, 40% of posterior and 2% of fundal locatio n of

placenta. It is found that 7% of the sample size had

hypertension, at 3% of anterior and 4% of posterior. It was also

obtained that the pregnant mother who had diabetes constitute

only 6% of the sample size, which 4% of it was anterior and 2%

of it was posterior placental location.

49

5-3. Recommendations

Based on the above findings and observations, it is

recommended that: -

Assessment of placenta location should be made in order

to follow up both pregnancy and prenatal obstetrical care.

Further studies should be made in order to comprehend if

the placental location has an influence on the amniotic

fluid volume, estimated fetal weight and the maternal

medical conditions, like: - gestational diabetic and

pregnancy induced hypertension.

Further Study should be done using larger sample for

same GA.

In addition to the routine technique of using longitudinal

and transverse of transabdominal scan, the sonographers

should perform a transvaginal scan to assess the placental site more

accurately if there is any doubt about placental position.

50

References:

1. http://jpsionline.com/admin/php/uploads/199_pdf.pdf

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4612913/

3. http://dergipark.gov.tr/download/article -file/130256

4. https://quizlet.com/28358289/child-development-flash-

cards/

5. Collins, Arulkumaran, hayes, Jackson, Impey (2013).

Oxford Handbook of Obstetrics and Gynaecology, 3 t h

Edition, Oxford University Press, 18 -24.

6. http://www.phschool.com/atschool/florida/pdfbooks/sci_M

arieb/pdf/Marieb_ch28.pdf

7. Norman C. Smith. A. Pat M. Smith.(2006),Obstetrics and

Gynaecological Ultrasound Made Easy, Second Edition,

Elsevier Limited, 122.

8. Phillip Bennett. Catherine Williamson.(2010), Basic

Science in Obstetrics and Gynaecology, 4 t h Edition,

Elsevier Limited, 41-55.

9. Burwin Institute

10. http://pubs.rsna.org/doi/pdf/10.1148/rg.295085242

11. https://pdfs.semanticscholar.org/1ba3/f1b9f0337829b

bdfe2d73e13614336f57df8.pdf

12. http://onlinelibrary.wiley.com/doi/10.1002/jcu.1870010106

/abstract

51

13. http://www.jaypeejournals.com/eJournals/ShowText.aspx?I

D=58&Type=FREE&TYP=TOP&IN=_eJournals/images/JPL

OGO.gif&IID=7&isPDF=NO

14. http://shodhganga.inflibnet.ac.in/bitstream/10603/79035/4/

chapter%201.pdf

15. http://www.embryology.ch/anglais/fplacenta/circulplac01.h

tml

16. Sandra L. Hagen-Ansert(2012), Diagnostic Sonography,7 t h ,

Addition,Vol.1, Elsevier Limited,1082

17. https://studfiles.net/preview/6132217/page:3/

18. https://academic.oup.com/edrv/article/27/2/141/2355234

19. http://www.ejog.org/article/0028-2243(80)90047-7/pdf

20. http://www.iosrjournals.org/iosr-jdms/papers/Vol13-

issue5/Version-3/B013530609.pdf

21. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.8

34.116&rep=rep1&type=pdf

52

Appendices

53

Appendix (A)

The National Ribat University

College of Postgraduate Studies and Scientific

Research

Afro-Asian Medical Training Center

Assessment of the Placental Location in the

Third Trimester Using Ultrasound

Data collection sheet

Mother Age

Number of Featus in Pregnancy

Gestational Age

Mode of Previous Delivery

Gestational Hypertension

Gestational Diabetes

Fetal Presentation,

Estimated Fetal Weight

Amniotic Fluid Volume

Gravidity

54

Appendix (B)

Image (1) : Normal Anterior Placenta TAS image at 39 weeks

gestation shows a normal anterior placenta . Taken from

Omdurman Maternity Hospital on 30-10-2017.

55

Image(2) Normal Fundal Placenta TAS image at 33 weeks

gestation shows a normal Fundal placenta extending into the

Posterior of the uterus. Taken from Omdurman Maternity

Hospital on 13-11-2017.

56

Image(3) : Normal Posterior Placenta TAS image at 34 weeks

gestation shows a normal Posterior placenta . Taken from

Omdurman Maternity Hospital on 27-11-2017.

57

Image(4) Normal Posterior Placenta TAS image at 37 weeks

gestation shows a normal Posterior placenta extending into the

lower segment of the uterus. Taken from Omdurman Maternity

Hospital on 27-11-2017.

58

Image(5) Upper posterior Placenta TAS image at 35 weeks

gestation shows Upper Posterior placenta. Taken from

Omdurman Maternity Hospital on 23-11-2017.

59

Image (6) : Normal Anterior Placenta . TAS image at 34 weeks

gestation shows Anterior placenta. Taken from Omdurman

Maternity Hospital on 21-11-2017.

60

Image (7) : Normal Fundal Placenta. TAS image at 34 weeks

gestation shows Normal Fundal placenta. Taken from Omdurman

Maternity Hospital on 04-12-2017.

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Image (8) : Normal Posterior Placenta TAS image at 38 weeks

gestation shows a normal Posterior placenta. Taken from

Omdurman Maternity Hospital on 04-12-2017.