GROWTH AND DEVELOPMENT OF PRENATAL PERIOD

SHINU K ANTONY

Ist YEAR MSc NURSING

GOVT COLLEGE OF NURSING

ALAPPUZHA

PERIODS IN PRENATAL DEVELOPMENT

• Ovular period or germinal period: This lasts for first 2 weeks following ovulation.

• Embryonic period: Begins at 3rd week following ovulation and extends upto 10 weeks of gestation

• Fetal period: Begins after 8th week following conception and ends in delivery

GAMETOGENESIS

Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes

FERTILIZATION

Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube

ZYGOTE

PLACENTATION

PRINCIPLES EVENTS

• Days 14-21 post conception: notochord develops, ectoderm thickens to form neural plate and neural folds.

• Days 21-28 post conception: neural folds fuses to form neural tube. Four primitive cardiac chambers. First heart beat on day 21.

• Weeks 4-6 post conception: optic vesicles appear, complete neural tube closure (D30). Limb buds appear. Formation of face.

• Weeks 8-12 post conception: external genetalia develop

PRINCIPLE EVENTS…………….

• Weeks 20: skin is covered with lanugo. Vernix caeosa is present.

• Weeks 28: testes descend to the internal inguinal ring

• Weeks 36: one testicle usually descends into the scrotum. Lanugo tends to disappear.

• Weeks 40: both the testicles descend into the scrotum. Nails project beyond the finger tips. Posterior fontanelle is closed.

FETAL PHYSIOLOGY

Nutrition: Three stages of fetal nutrition• Absorption• Histotrophic transfer• HematotrophicFetal blood:• Haematopoiesis first in yolk sac by 14th day.• 10th week the liver becomes the major site.Leucocyte: Leukocytes appear after 2 month of gestationUrinary system : • the end of first trimester- nephrons are active • near term the urine production rises to 650ml per

day.

skin :• At 16th week, lanugo• Sebaceous glands at 20th week and and the sweat

glands later.Gastrointestinal tract: • As early as 10-12week, the fetus swallows amniotic

fluid. • The meconium appears from 20th week.Respiratory system: • At 28th week, alveoli expand and are lined by cuboidal

epithelium. • At the end of 24th week lung surfactantFetal endocrinology: Growth hormone, ACTH, prolactin, TSH and gonadotropin hormones are produced by fetal pituitary as early as the 10th week.

FETAL CIRCULATION

PRENATAL CARE

Systemic supervision (examination and advice) of a women during pregnancy is called antenatal / prenatal care. It comprises of•Careful history taking and examination (general and obstetrics)

•Advice given to the pregnant women

AIMS • To screen the high risk cases• To prevent or detect and treat at the earliest any

complications• To ensure continued medical surveillance and

prophylaxis• To educate the about the physiology of pregnancy

and labour by demonstrations, charts and diagrams• To discuss with the couple the place, time, mode and

the delivery, provisionally and the care of new born• To motivate to the couple the need of family planning

and also appropriate advice to the couple seeking MTP

The objective is to ensure a normal pregnancy with delivery of a healthy baby from a healthy mother.

OBJECTIVE

PROCEDURES AT FIRST VISIT

HISTORY COLLECTIONPHYSICAL EXAMINATIONGeneral examinationObstetrical examinationinvestigations

PROCEDURE AT SUBSEQUENT VISITObjectiveTo assess fetal well being Lie, presentation, position and number of fetusAnemia, preeclampsia, amniotic fluid volume and fetal growthTo organize specialist antenatal clinics for patients with problem like cardiac disease and diabetics.To select time for USG, amniocentesis or CVS when indicated.

Antenatal assessment of fetal wellbeing

AIMS OF ANTENATAL FETAL MONITORING

• To ensure satisfactory growth and well being of the fetus throughout pregnancy

• To screen out the high risk factors that affect the growth of the fetus

INDICATIONS OF ANTEPARTUM FETAL MONITORING

• Pregnancy with obstetric complications• Pregnancy with medical complications• Others like advanced maternal age, previous still birth, birth of a baby with structural abnormality etc

• Routine antenatal testing

NONINVASIVE PRENATAL TESTS

•Fetal ultrasonography•Fetal echocardiogram•Computerized Tomography and MR imaging•MS-AFP and triple test•Fetal Nuchal Translucency

INVASIVE PRENATAL TEST

AminocentesisChorionic villus samplingCordocentesis or percutaneous umbilical blood sampling

Fetal tissue sampling

METHODS OF PRENATAL DIAGNOSIS

AMNIOCENTESIS CHORION VILLOUS SAMPLING

ULTRASONOGRAPHY

METHODS OF PRENATAL DIAGOSIS

PERCUTANEOUS UMBILICAL BLOOD

SAMPLINGFETOSCOPY

GENETIC TESTING

METHODS OF PRENATAL DIAGNOSIS

MATERNAL SERUM SAMPLE

PREIMPLANTATION DIAGNOSIS

DEFINITION OF GENETICS

The branch of biology that deals with heredity and variation.

BRANCHES OF GENETICS

CYTOGENETICSIT IS THE BRANCH OF GENETICS THAT CORRELATES

WITH THE STRUCTURE, NUMBER AND BEHAVIOR OF

CHROMOSOMES

BRANCHES OF GENETICS

MOLECULAR GENETICSIT IS THE BRANCH OF GENETICS WITH THE STRUCTURE

AND ACTIVITY OF GENETIC MATERIAL AT MOLECULAR LEVEL.

GENOMICS

It involves all of the genes in human genome together including their interaction with each other, with the environment and their influence on psychosocial and cultural factors.

PHENOTYPE A PERSONS OBSERVABLE CHARACTERISTICS OF HIS OR HER GENOTYPE

GENOTYPE A PERSONS UNIQUE GENETIC DISTRIBUTION

HISTORY OF GENETICS

FATHER OF GENETICSGREGOR MENDEL

Discovered fundamental law of genetics

In 1853 Mendel conducted his

experiments on garden peas (Pisum

sativum).

CHROMOSOMES

In human body 23 pairs of chromosomes are there. Out of these 22 are autosomes and one pair sex chromosomes

STRUCTURE OF DNA

Double helix structure

GENE :- Unit of heredity

CELL DIVISION

MITOSIS MEIOSIS

STAGES OF CELL DIVISION

Interphase Prophase

STAGES OF CELL CYCLE

Metaphase Anaphase

STAGES OF CELL CYCLE

Telophase

GENETIC TESTING

GENETIC TESTING Genetic testing refers to the analysis of a

person’s DNA, chromosomes, proteins or certain metabolites obtained from a sample of blood or other body tissue in order to detect changes that indicate the presence or absence of a genetic condition or a pre disposition to develop one.

[JOYCE M BLACK, 2010] Genetic screening is presumptive

identification of an unrecognized genetic predisposition for a future disease in individual or their progency for which preventive or disease course altering interventions exist.

PURPOSES OF GENETIC TESTING

To confirm a present condition.

To determine whether an

individual is a carrier of a genetic

condition.

To detect fetal abnormalities.

To predict diseases in

asymptomatic individual

INDICATIONSOne or more birth defects

A genetic disorder

A chromosome abnormality

Intellectual development disorder or developmental delay

Neuromuscular abnormalities

Unexplained metabolic problems

Congenital or familial hearing loss of blindness

Abnormal sexual development

Prenatal exposure to drugs or medications including alcohol

Cancer

APPROACHES

GENOTYPE

PHENOTYPE

TYPES OF GENETIC TESTING

NEW BORN SCREENING

PRENATAL DIAGNOSIS

TYPES OF GENETIC TESTING

DIAGNOSTIC TESTING

CARRIER TESTING

TYPES OF GENETIC TESTING

PREDICTIVE TESTING

PRE IMPLANTATION TESTING

TYPES OF GENETIC TESTING

FORENSIC TESTINGRESEARCH TESTING

TYPES OF GENETIC TESTING

PHARMACOGENOMICS GENETIC ANCESTRY TESTING

METHODS OF GENETIC TESTING

MOLECULAR GENETIC TESTS

CHROMOSOMAL GENETIC TESTS

BIOCHEMICAL GENETIC TESTS

MOLECULAR GENETIC TESTS

I. AMPLIFICATION POLYMERASE CHAIN REACTION CLONING DNA IN BACTERIA

II. SEPERATION AND DETECTION CELL CULTURES

III. DNA ISOLATION

CHROMOSOMAL GENETIC TESTS KARYOTYPING HIGH RESOLUTION BANDING SOMATIC CELL HYBRIDIZATION FLOW CYTOMETRY FLURESCENT INSITU

HYBRIDIZATION

BIOCHEMICAL GENETIC TESTS

Study of body's enzymes

ASSESSMENT OF FETAL WELLBEING IN LATE PREGNANCY

CLINICAL BIOCHEMICAL BIOPHYSICAL

Click icon to add pictureAssessment of fetal lung maturity

• Estimation of lecithin:sphingomyelin ratio• Shake’s test or bubbles test or Clement’s• Foam stability index• Thin layered chromatography• Measurement of saturated phosphatidyl

choline• Fluorescence polarization• Amniotic fluid optical density• Lamellar body count• Orange colored cells• Amniotic fluid turbidity

Click icon to add pictureASSESSMENT OF SEVERITY OF RH-ISOIMMUNIZATION

It is done by amniocentesis for estimation of bilirubinin the amniotic fluid by spectrometric analysis. The optical density difference at 450nm gives the prediction of the severity of fetal hemolysis

Click icon to add pictureBIOPHYSICAL PROFILEI.FETAL MOVEMENT COUNT1. Fetal movement count 10 formula2. Daily fetal movement count (DFMC)3. Doppler imaging

II.VASIII.NONSTRESS TESTiv.BIOPHYSICA L PROFILEv.MODIFIED BPP

BIOPHYSICAL

PROFILE

Observation

for 30 minutes

SCORING

(MANNING-1985)

Normal score =2

abnormal=0

parameters Minimal normal criteria score

Non stress test(NST)

Fetal breathing

movements

Gross body

movement

Fetal muscle tone

Amniotic fluid

Reactive pattern

One episode lasting >30sec

3discrete body or limb

movements

1 episode of extension (limb

or trunk) with return of

flexion

1 pocket measuring 2cm in

two perpendicular planes

2

2

2

2

2

BPP score Interpretation management

8-10

6

4

0-2

No fetal asphyxia

Chronic asphyxia

Chronic asphyxia

Certain asphyxia

Repeat testing at

weekly interval

If >36wk deliver

If >=36wk deliver, if

<32wk repeat testing

in 4-6hrs

Test for 120mts,

persistent score <=4

deliver regardless of

gestational age

Click icon to add pictureVI.FETAL CARDIOTOCOGRAPHY

VII.ULTRASONOGRAPHY

VIII.DOPPLER ULTRASONOGRAPHY

IX.CONTRACTION STREE TEST

CONGENITAL MALFORMATIONS

Maternal factor Fetal / infant risks

Adolescent age,

pregnancy that

occurs at the two

age extremes

<16yrs and

35yrs.

Advanced

maternal age

issues

Small maternal

size

Large maternal

size

Nutrition

Prenatal care

Support system

Socioeconomic system

Preeclampsia

IUGR

LBW

Chronic diseases that affect pregnancy

Increased incidence of chromosomal abnormalities

Pregnancy related conditions might occur eg. Diabetes,

preeclampsia,vaginal bleeding

Increased risk of congenital or chromosomal abnormalities

IUGR

Increased potential for hypoxia during labor and delivery

Increased risk for poor fetal nutrition

Chromosomal(6%)

Trisomy 21 (down’s syndrome)

Trisomy 18 (Edward’s syndrome

Trisomy 13 (Patau’s syndrome)

Single gene disorder(5%)

1. Autosomal 2. X-linked

Infections(2%)

Rubella CMV Varicella Parvo

virus Toxoplas

ma

Maternal illness (5%)

Diabetes epilepsy

Drugs & environment(1-2%)

warfarin lithium dilantin radiation alcohol hypoxia

Mutifactorial (20%)

neural tube defects

congenital heart defects

cleft palate & lip

CAUSES OF CONGENITAL DISORDERS

SINGLE GENE DISORDERS

Click icon to add pictureAutosomal dominant (70%)• achondroplasia• marfans syndrome • neurofibromatosis• recessive (20%)• cystic fibrosis • galactosemia• sickle cell anemiaX linked disorders (recessive- 5%, dominant- rare)• hemophilia• duchenne muscular dystrophy• color blindness • fragile X syndrome

PATTERNS OF INHERITANCE

I. AUTOSOMAL DOMINANT INHERITANCE

VERTICAL PATTERN OF INHERIANCE

MALES AND FEMALES ARE EQUALLY AFFECTED.

50% OF CHANCE OF INHERITNG NORMAL GENE AND 50% OF MUTATED GENE

PATTERNS OF INHERITANCE

II. AUTOSOMAL RECESSIVE INHERITANCE HORIZONTAL PATTERN OF

INHERITANCE.

RELATIVES OF SINGLE GENERATION TEND TO HAVE THE CONDITION.

WHEN CARRIERS HAVE CHILDREN TOGETHER,25% CHANCE OF INHERITING MUTATED GENE.

III. X LINKED DOMINANT INHERITANCE

The sons of a man with an X-

linked dominant disorder will not

be affected, but all of his daughters

will inherit the condition.

A woman with an X-linked

dominant disorder has a 50

percent chance of having an

affected daughter or son with each

pregnancy.

PATTERNS OF INHERITANCE

IV. X LINKED RECESSIVE INHERITANCE . The sons of a man will

not be affected, and his daughters will be carrier.

a woman has a 50 percent chance of having sons who are affected and a 50 percent chance of having daughters who carry one copy of the mutated gene.

PATTERNS OF INHERITANCE

V. Y LINKED INHERITANCEMale to male

transmission.Only males are

affected.

PATTERNS OF INHERITANCE

VI. MULTIFACTORIAL INHERITANCECaused by a

combination of genetic and environmental factors

GENETIC DISORDERS

CHROMOSOMAL ABNORMALITIES

(cytogenic disorders)Nondisjunction abnormalitiesDeletion abnormalitiesTranslocation abnormalitiesMosaicismisochromosomes

GENETIC DISORDERS

III. SEX CHOMOSOME ABNORMALITIES

TURNERS SYNDROME

KLINFELTERS SYNDROME

SINGLE GENE DISORDERS

•cystic Fibrosis•Tay Sach Disease•Sickle cell disease

Autosomal

recessive inheritan

ce

•Neurofibromatosis•Huntington's disease•Achondroplasia

Autosomal

dominant inheritan

ce

SINGLE GENE DISORDERS

•Vitamin D Resistant Rickets•Rette syndrome

X Linked Dominan

t Inheritan

ce

•Hemophilia•Color Blindness•Duchenne Muscular Dystrophy

X Linked Recessiv

e Inheritan

ce

SINGLE GENE DISORDERS

•Alzheimers Disease•Diabetes Mellitus•Cancer

Multifactori

al Inheritance

GENETIC DISORDERS

•Phenylketonuria•Maple Sugar Urine Disease•Homocystinuria

Inborn Errors

Of Metabolism

GENETIC COUNSELLING

GENETIC COUNSELLING

DEFINITIONGenetic counselling is the process in which patients or their relatives at the risk of genetic disorder are made aware of the consequences of the disorder, its transmission ant the ways by which this can be prevented or mitigated.

[GANGANE SD, 2008]

Genetic counselling is defined as a communication process which deals with the human problems associated with the occurrence or the risk of a genetic disorder in a family

[THE AMERICAN SOCIETY OF HUMAN GENETICS, 2008]

AIMS

To obtain a full history.

To establish an accurate diagnosis.

To draw the family tree.

To estimate the risk of a future pregnancy

being affected or carrying a disorder.

To give information on prognosis and

management.

To provide continued support and follow up.

To do genetic screening

Indications Advanced parental age

Previous child with or family history of

Congenital abnormality

Adult onset genetic disease (pre symptomatic

testing)

Consanguinity

Teratogen exposure (occupational abuse)

Repeated pregnancy loss or infertility

Pregnancy screening abnormality

Heterozygous screening based on ethnic risk

Follow up testing

TYPES OF GENETIC COUNSELLING

DIRECTIVE

NON DIRECTIVE

TYPES OF GENETIC COUNSELLING

RETROSPECTIVE

PROSPECTIVE

GENETIC COUNSELLING TEAM The family or referring physician

The geneticist

The nurse

The other members of helping professions.

INFORMATIONS CONVEYED The specific condition or conditions

Knowledge of the diagnosis of the particular condition

Natural history of the condition

Genetic aspect of the condition and recurrence risk

Prenatal diagnosis and prevention

Therapies and referral

Support groups

Follow up

Nondirective counseling

The magnitude of the risk of occurrence or recurrence

The impact of disease on the patient and the family

Modification of disease impact and/ or risk

Anticipated future development

LEGAL AND ETHICAL ISSUES

OF GENETIC COUNSELLING

ROLE OF NURSE N GENETIC COUNSELLNG

ASSESSMENT

IDENTIFICATION

PROVIDING EDUCATION,CARE AND SUPPORT

FOLLOW UP

PRENATAL DIAGNOSTIC

TECHNIQUE ACT(PNDT) 1994

CONGENITAL MALFORMATIONS IN NEWBORN AND THE SURGICAL EMERGENCIES

Imperforate anus Esophageal atresia Meconium ileus Exomphalos / omphalocele Congenital diaphragmatic hernia

(CDH) Duodenal atersis

Emerging Methods of Fetal Assessment

Fetal physiology assessment

Fetal magnetoencephalography

NEW TECHNOLOGIES

STEM CELL PRESERVATION AND IMPLANTATION

NEW TECHNOLOGIES

Diseases for applying gene therapy

Disease Defect Target cell

Severe combined Bone marrow cells or

immunodeficiency T-lymphocytes

Hemophilia Liver, muscle

Cystic fibrosis Lung Cells

Cancer Many cell types

Neurological diseases Parkinson’s/ Alzheimers Nerve Cells

Infectious diseases AIDS, hepatitis B White Blood Cells

BIBLIOGRAPHY Dedas. A.K screening And Diagnosis Of Fetal

Malformation: A Practical Guide. Newdelhi. B. I Publication.2004

Hiralal konar. D. C Dutta’s textbook of obstetrics. 7th ed. India. New central book agency private limted. 2009

Randhawa S. S. atext book of genetics. 3rd ed. India. Vikas & company medical publishers. 2010

Terrikyle & susan carman. Essentials of paediatric nursing. 2nd edition. Newdelhi. Wolters kluwer Lippincott Williams & wilkins. 2013

Anoop kumar tiwar. Human genome project: an overview. Hitkarini journal of modern nursing services (HJMNS). Jan-june 2012.volumeII. issue I. page numbers 22-23

World Health Organisation (WHO). Geneva. Woldheath organisatation;2011. Available from:http://www.whocc.org/