1. Physiology of Pregnancy
Liu Wei
Department of Ob & Gy
Renji hospital

2. Normal Pregnancy Pregnancy
The course that the embryo and the fetus grow in the maternal body
Stages of pregnancy
Early pregnancy: ≤12 weeks
Mid pregnancy: ≥13 weeks,≤27 weeks
Late pregnancy:≥28 weeks
Term pregnancy:≥37 weeks,<42 weeks

3. Formation of Embryo Fertilization Place: oviduct (ampulla) Process
capacitation → acrosome reaction→ penetrate the zona pellucida→ second meiosis →zygote

4. Formation of Embryo Implantation requirement
Disappear of zona pellucida
Formation of syncytiotrophoblast
Synchronized development of blastocyst and endometrium
Adequate progesterone

5. Formation of Embryo Process
morula (day 3) → enter uterine cavity (day 4) → early blastocyst→ late blastocyst (day 6-7) → implantation
location→ adherence→ penetration

6. Development of embryo and fetus
Definition
embryo: ≤ 8 weeks
Fetus: ≥ 9 weeks, human shape

7. Development of embryo and fetus
Physiology of fetus
Circulation
fetus ←→placenta←→ mater
1 umbilical vein (full of oxygen), 2 umbilical artery (lack of oxygen)
Mixed blood (vein and artery)

8. Development of embryo and fetus

9. Development of embryo and fetus
Hematology
Erythropoiesis
From yolk sac: 3 weeks
From liver: 10 weeks
From bone marrow and spleen: term (90%)
EPO production: 32nd week

10. Development of embryo and fetus
Fetal hemoglobin
Fetal hemoglobin: early pregnancy
Adult hemoglobin: 32nd week
Term: fetal type Hb 25%
White cells
Leukocytes: 8 week
Lymphocytes (antibody production): 12 week, thymus and spleen

11. Development of embryo and fetus
Gastrointestinal tract
drink amniotic fluid: 4th month
no proteolytic activity
enzymatic deficiencies in liver:
bilirubin is not easy to be clear.

12. Development of embryo and fetus
Kidney
Its function begins at 11-14th week
Endocrinology
Fetal thyroid: the first endocrine gland (6th week), synthesize thyroxine at 12th week
Fetal adrenal cortex: widen (20th week), a fetal zone. synthesize steroid hormones (E3, liver placenta mater)

13. Placenta Structure Primary villus syncytiotrophoblast cytotrophoblast
Secondary villus
third class vilus
fetal capillary enter the stroma

15. Placenta Function metabolism Exchange of O2 and CO2
Exchange of nutritive factors and waste
Defensive
Limited. IgG, virus, drug

16. Placenta Endocrine HCG HPL E P Oxytocinase
Cytokines and Growth Factors
Immunity tolerance

17. Fetal membranes Structure chorion and amnion Amnion
A double-layered translucent membrane
Become distended with fluid

18. Umbilical Cord Structure
amnion, yolk sac, one vein, two artery and Wharton jelly
Length
30-70cm

19. Amniotic fliud Source exudation of fetal membranes (early pregnancy)
Fetal urine
Fetal lung
Exudation of amnion and fetal skin

20. Amniotic fliud Absord Fetal membrane Umbilical cord Fetal skin
Fetal drinking
Feature
ml at 36th-38th week (peak), transparent → slightly turbid

21. Amniotic Fliud Function Protect fetal move freely, warm Protect mater
prevent infection

22. Physiologic changes in pregnant woman
Genital organs
Uterus
capacity: 5ml-5000ml.weight: 50g-1000g
Hypertrophy of muscle cells
Endometrium→decidua: basal decidua, capsular decidua, true decidua
Contraction: Braxton Hicks
Isthmus uteri: 1cm→ 7-10cm

24. Physiologic changes in pregnant woman
Cervix: colored
Ovary: placenta replaces ovary (10th week)
Vagina: dilated and soft, pH↓(anti-bacteri bacteria)
Ligaments: relaxed

25. Physiologic changes in pregnant woman
Cardiovascular system
Heart:
move upward, hypertrophy of cardiac muscle
Cardiac Output
increase by 30%, reach to peak at 32nd –34th week
Blood pressure
early or mid pregnancy Bp↓.late pregnancy Bp↑ .Supine hypotensive syndrome

26. Physiologic changes in pregnant woman
Hematology
Blood volume
Increase by 30%-45% at 32nd –34th (peak)
Relatively diluted
Composition
Red cells
Hb:130→110g/L, HCT:38%→ 31%.
White cells: slightly increase
Coagulating power of blood: ↑
Albumin: ↓,35 g/L

27. Physiologic changes in pregnant woman
The Respiratory system
R rate: slightly ↑
vital capacity: no change
Tidal volume: ↑ 40%
Functional residual capacity:↓
O2 consumption: ↑ 20%

28. Physiologic changes in pregnant woman
The urinary system
Kidney
Renal plasma flow (RFP):↑35%
Glomerular filtration rate (GFR):↑ 50%
Ureter
Dilated (P↑)
Bladder
Frequent micturation

29. Physiologic changes in pregnant woman
Gastrointestinal system
Gastric emptying time is prolonged→ nausea.
The motility of large bowel is diminished → constipation
Liver function: unchanged

30. Physiologic changes in pregnant woman
Endocrine
Pituitary (hypertrophy)
LH/FSH: ↓
PRL:↑
TSH and ACTH:↑
Thyroid
enlarged (TSH and HCG↑)
thyroxine↑ and TBG↑ → free T3 T4 unchanged

31. END