Physiology of pregnancyPhysiology of pregnancy
Zhao aimin
Definition of pregnancyDefinition of pregnancy
Pregnancy is defined as the course of embryo and fetal growth and development in uterine
It begain at the fertilization and end the delivery of the fetal and it’s attachment
Definition of fertilazationDefinition of fertilazation
Fertilization is defined as the course of combination of the oocyte and sperm
It onset 12h after ovulation usually in ampulla of the oviduct(fallopian tube)
The Development of the The Development of the fertilizatedfertilizated eggegg
3 days after ovulation, the morula (early blast)is fomulated
4 days after ovulation, the late blast is fomulated
6-7 days after ovulation, the egg imbeds in the uterus
The stage of egg imbedThe stage of egg imbed
Apposition Adhesion Penetration
The necessary conditions The necessary conditions of imbedof imbed
Disapearing of the pellucid zone Syntrophoblast formed from the
blast Synchronizing development of blast
and the endometriun P Secretory enough
Changes of endometrium after Changes of endometrium after the egg imbedthe egg imbed
The endometrium changes into dicedua
Basal decidua Capsular
decidua True decidua
Attachment of the fetalAttachment of the fetal
Placenta Fetal membranes Umbilical cord Amniotic fluid
placentaplacenta
It’s an exchange organ between maternal and fetal
Amniotic membrane chorion frondosum Basal decidua
chorion frondosumchorion frondosum 13-21 days after ovulation, villi
fomulating gradually Grade I viili Grade II Iviili Grade III viili
Structure of placentaStructure of placenta
Round Weight:450-650g Diameter:16-20cm Thickness:1-3cm
thick in center and thin in margin
Function of placentaFunction of placenta
One important function of placenta is substance exchange between maternal and fetal
The position of exchange is VSM(vasculo-syncytial membrane)
VSM is comprised of
Syntrophoblastocyte
Basal membrane of Syntrophoblastocyte
Stroma of villi
Basal membrane of capillary
Endothelium of capillary
The way of substance exchange
Simple diffusion
Facilitated diffusion
Active transportion
phagocytosis
The functions of placenta Gas exchange
Suply of nutrition
Depletion of fetal product of metabolisn
Defense functionHormone synthesis
Human chorionic gonadotropin(HCG)
Human placental lactogen(HPL)
Pregnancy specific -glycoprotein(PS 1G)
Human chorionic thyrotropin(HCT)
Estrogen, P, Oxytocinase, heat stable alkaline
phosphatase(HSAP)
Fetal membrane Chorion
Amnion
Umbilical cord Length:30-70cm average:50cm
Consist of 2 artery and 1 vein
Amniotic fluidSource: early from serum dialysis
late fron fetal urine
Absorse: by fetal membrane, fetal
swallowing(500ml/day)
Amniotic exchange: between maternal
and fetal 400ml/h
Volume of amniotic fluid 8 weeks:5-10ml
10 weeks:30ml
20 weeks:400ml
38 weeks:1000ml
Status of amniotic fluid pH:7.20
Density:1.007-1.025
Contained: water(98-99%)
inorganic substance
organic substance(1-2%)
The function of amniotic fluid
Protect maternal and fetal
Maternal changes during pregnancy
The maternal system may produce a series of changes in order to adapt to the needing of fetal growth and development influenceed by placenta hormone and neuro-endocrine
Changes of reproductive system
Uterus
Body: become enlargement and soft
from 7×5 ×3cm pre-pregnancy to
35×25 ×22cm at term
Volume of uterus cavity:
become enlargement from 5ml pre-pregnancy to 5000ml.at term
Weight: be increased from from 50g pre-
pregnancy to 1000g at term
Wall: become thickness and the thickist at mid-
period from 1 cm pre-pregnancy to 2-2.5
cm at term
Blood suply:blood flow increased significantly
upto 500- 700ml/min,increased 4-6
times and most of blood flow is
transported to the placenta(80-85%)
Isthmus: be dialated and become soft from 1cm
pre-pregnancy a portion of the uterus
after 12 gestational weeks
Cervix: be soft and coloration or stain
secrete amount of mucus avoiding the
uterus cavity suffer from infection
Changes of ovary Stop ovulation
Corpus luteum formation and maintains for
10 weeks
And the function of corpus luteum is
substituted by the placenta
Corpus luteum atretic gradually after 3-4
months gestation.
Changes of the circulation Heart border: become enlargement
Heart rate: increased 10-15 beat per min at the
late pregnancy
Heart volume: increased 10% at the late
pregnancy
Cardiac outputVery important for fetal growth and development
Incrased begain 10 weeks and upto the peak at 32 weeks
80ml/bp and keeps the level to the term pregancy
Blood pressure changes due to pregnancy
No obvious change in Systolic pressure
Mild decreased in diastolic pressure
Vein pressure No significantly changes in Upper limb vein
pressure
Lower limb vein pressure increased because of
the disturbance of vein reflux
Changes of blood systemVolume: increased (30-45% ) begain 6- 8 weeks
and up to the peak at 32-34 weeks
increased about 1500ml including
plasma 1000ml and red cell 500ml
Changes of blood component
Red cell: reticulocyte increased
red cell decreased 3.6×1012(4.2×1012)
Hb decreased 110g/L(130g/L)
WBC: neutrophilic granulocyte increased
lymphocyte mild increased
no change in orther blood cells
CoagulationHypercoagulability
Factor increasedⅱⅴⅶⅷⅨⅹ
ESR increased significantly upto 100mm/h
Plasma protein
albumin decreased
