1. Physiology of Pregnancy
Weirong Gu
Obsterics & Gynecology Hospital of Fudan university

2. pregnancy
The condition of being with child or gravid, is the process of embryo and fetus growing and developing in the uterus
From the fertilization to the expelling of the fetus with placenta and membranes

3. contents
fertilization, development, transport and implantation of fertilized ovum
formation and function of fetal attachment
maternal changes during pregnancy

4. concepts sperm capacitation fertilization acrosome reaction
zona reaction

5. sperm capacitation Spermatozoons contact with endometrium
the α-/β- amylase remove the decapacitation factor on spermatozoons’ acrosomal enzyme
the spermatozoons with the ability of fertilization(capacitation)in uterus and fallopian tubes
Semen enters vagina

6. acrosome reaction
Acrosome rupture, acrosomal enzyme released and lysis the radiate corona and zone pellucida
The spermatozoons penetrate and fuse with oocyte

7. zona reaction
the cortical particle of cytoplasm release lysosomal enzyme
zona structure changed and sperm receptor degenerated to prevent other sperm into the zona

8. fertilization The course of combination of the oocyte and sperm
Time : 12h after ovulation
Place : usually in ampulla of the oviduct (fallopian tube)
It onset 12h after ovulation usually in ampulla of the oviduct (fallopian tube)

9. development and transport of the zygote
3days after ovulation, the morula (early blast) is fomulated
4days after ovulation, the late blast is fomulated
6-7days after ovulation, the egg imbeds in the uterus
Cleavage , blastomere
72h morula
4d, early blastocyst, Enter uterine cavity
5-6d, zona disappear
11-12d, late blastocyst,implantation

10. implantation Late blastosphere implanted in endometrium Apposition
Adhesion
penetration

11. The necessary condition of implantation
Disapearing of the zona pellucid
Formation of syncytiotrophoblast
Synchronizing development of blastocyst and endometrium
Adequate progesterone

12. Changes of endomertium after implantation
The endometrium changes into dicedua
Basal decidua
Capsular decidua
Ture decidua

13. Embryo and fetal development
Embryo: the first 8 weeks from pregancy
Fetus: after 9 weeks from pregnancy ,human shape

14. 12 Gestational Weeks
The uterus usually is just palpable above the symphysis pubis, and the fetal crown-rump length is 6 to 7 cm.
Centers of ossification have appeared in most of the fetal bones, and the fingers and toes have become differentiated.
Skin and nails have developed and scattered rudiments of hair appear.
The external genitalia are beginning to show definitive signs of male or female gender.
The fetus begins to make spontaneous movements.

15. 16 Gestational Weeks fetal crown-rump length: 12 cm weight : 110 g
Gender can be determined by 14 weeks
Gender can be determined by experienced observers by inspection of the external genitalia by 14 weeks.

16. 20 Gestational Weeks
Weight: more than 300 g, and increase in a linear manner
Movement: about every minute and is active 10 to 30 percent of the time
skin : less transparent, a downy lanugo covers entire body, some scalp hair has developed.
This is the midpoint of pregnancy as estimated from the beginning of the last menses.
The fetus now weighs somewhat more than 300 g, and weight begins to increase in a linear manner.
From this point onward, the fetus moves about every minute and is active 10 to 30 percent of the time (DiPietro, 2005).
The fetal skin has become less transparent, a downy lanugo covers its entire body, and some scalp hair has developed.

17. 24 Gestational Weeks The fetus now weighs about 630 g.
The skin is characteristically wrinkled, and fat deposition begins.
The head is still comparatively large, and eyebrows and eyelashes are usually recognizable.
The canalicular period of lung development, during which the bronchi and bronchioles enlarge and alveolar ducts develop, is nearly completed.
A fetus born at this time will attempt to breathe, but many will die because the terminal sacs, required for gas exchange, have not yet formed.

18. 28 Gestational Weeks
The crown-rump length is approximately 25 cm, and the fetus weighs about 1100 g.
The thin skin is red and covered with vernix caseosa.
The pupillary membrane has just disappeared from the eyes.
The otherwise normal neonate born at this age has a 90-percent chance of survival without physical or neurological impairment.

19. 32 Gestational Weeks
The fetus has attained a crown-rump length of about 28 cm and a weight of approximately 1800 g.
The skin surface is still red and wrinkled.

20. 36 Gestational Weeks
The average crown-rump length of the fetus is about 32 cm, and the weight is approximately 2500 g.
Because of the deposition of subcutaneous fat, the body has become more rotund, and the previous wrinkled appearance of the face has been lost.

21. 40 Gestational Weeks
This is considered term from the onset of the last menstrual period.
The fetus is now fully developed.
The average crown-rump length is about 36 cm, and the weight is approximately 3400 g.

22. Physiology of fetus circulation Fetus---placenta---mother
1 umbilical vein (full of oxygen)
2 umbilical arteries (lack of oxygen)
Mixed blood ( vein and artery)
Ductus arteriosus
Foramen ovale
Ductus venosus

24. hematology erythropoiesis EPO production: 32nd week
From yolk sac: 3 weeks
From liver: 10 weeks
From bone marrow and spleen: term (90%)
EPO production: 32nd week
Fetal blood volume:125ml/kg of the fetus at term

25. Fetal hemoglobin White cells 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

26. Fetal respiratory system
The timetable of lung maturation and identification of biochemical indices of functional fetal lung maturity are important to the obstetrician
A sufficient amount of surface-active materials in the amniotic fluid is evidence of fetal lung maturity
Surfactant: produced by type Ⅱcells of the lung alveoli; active component is a specific lecithin or dipalmitoylphosphatidylcholine

27. Gastrointestinal tract
Swallowing begins at weeks, 16weeks, gastrointestinal function is established
Liver
Hepatic enzyme is lack during fetal period, a very limite capacity for converting free bilirubin to conjugating bilirubin

28. Urinary system Genital system
The fetal kidneys start producing urine at 12 weeks’ gestation. 7-14ml/d by 18 weeks, 27ml/hr or 650ml/d at term
Genital system
Genital organ is developed from 9 weeks of pregnancy(male), weeks(female)

29. Attachment of the fetal
Placenta
Fetal membranes
Umbilical cord
Amniotic fluid

30. placenta An exchange organ between maternal and fetal Organization
Amniotic membrane
Chorion frondosum
Basal decidua

31. Chorion frondosum
13-21 days after ovulation, villi fomulating gradually
Primary viilus
Syncytiotrophoblast
cytotrophoblast
Secondary villus
Third class villus
Fetal capillary enter the stroma

32. Structure of placenta Round Weight: 450-650g Diameter: 16-20cm
Thickness: 1-3cm
thick in center and thin in margin

33. Function of placenta
One important function of placenta is substance exchange between maternal and fetal
Transfer oxygen and nutrients from the mother to the fetus and conversely the transfer of carbon dioxide and other metabolic wastes from fetus to mother

34. The position exchange is VSM(vasculosyncytial membrane)
VSM is comprised of
Syntrophoblastocyte
Basal membrane of syntrophoblastocyte
Stroma of villi
Basal membrane of capillary
Endothelium of capillary

35. The way of substance exchange
Simple diffusion
Facilitated diffusion
Active transportion
phagocytosis

36. The function of placenta
Gas exchange
Suply of nutrition
Depletion of fetal product of metabolism
Defence function
Hormone synthesis
Human chorionic gonadotropin (HCG)
Human placental lactogen (HPL)
Pregnancy specific ß-glycoprotein (PS ß1G)
Human chorionic thyrotropin(HCT)
Estrogen, P, Oxytocinase, heat stable alkaline phosphatase(HSAP)

37. Fetal membrane Chorion Amnion A double-layered translucent membrane
Become distended with fluid

38. Umbilical cord
Extends from the fetal umbilicus to the fetal surface of the placenta
Length: 30-70cm average : 50cm
Diameter: cm
Consist of 2 artery and 1 vein, Wharton jelly
amnion, yolk sac

39. Amniotic fluid Source: Absorse:
early from serum dialysis
Mid-pregnancy from fetal urine
Late from fetal lung
Absorse:
fetal membrane
Umbilical cord
Fetal skin
Fetal fetal swallowing (500ml/day)
Amniotic exchange: between maternal and fetal 400ml/h
Volume: 50ml at 12 weeks, 400ml at midpregancy, 1000ml at term

40. Volume of amniotic fluid
8 weeks: 5-10ml
10 weeks: 30ml
20 weeks: 400ml
38 weeks: 1000ml

41. feature of amniotic fluid
pH: 7.20
Density:
Contained: water(98-99%)
inorganic substance
organic substance(1-2%)
Early transparent
Late slighty turbid

42. The function of amniotic fluid
Protect maternal and fetus
Move freely
Warm
Protect mother
Prevent infection
Serve to cushion the fetus, allowing musculoskeletal development and protecting it from trauma
Maintains temperature and has a minimal nutritive function
Promote the normal growth and development of the lungs and gastrointestinal tract

43. Maternal changes during pregancy
The maternal system may produce a series of changes in order to adapt to the needing of fetal growth and development influenced by placenta hormone and neuro-endorine

44. Changes of reproductive system
Uterus
Capacity : 5ml ml
Weight: 50g – 1000g
Hypertrophy of muscle cells
fundus-inferior portion-cervix
Endometrium –decidua
corpus:
Size: become enlargement and soft from 7*5*3cm pre-pregnancy to 35*25*22cm at term
Capacity : become enlargement from 5ml pre-pregnancy to 5000ml at term
Weight: be increased from 50g pre-pregnancy to 1000g at term
thickness: become thickness and the thickest at mid-period from 1cm pre-pregnancy to 2-2.5cm at term
The rate of the hypertrophy of different parts varies (fundus-inferior portion-cervix) so that the contractility decreases from fundus to cervix, the fetus is delivered

45. Blood supply Uterine contraction increases 4-6times (500-700ml/min)
Most transported to the placenta(80-85%)
Uterine contraction
Braxton hicks contraction-contraction without pain
Rare, irregular,and asymmetric
Intrauterine pressure: 5-25mmHg, duration <30s
blood flow increased significantly upto ml/min, increases 4-6times and most of blood flow is transported to the placenta(80-85%)

46. Isthmus Cervix softer and longer (1,7-10cm) lower segment Colored
Cerical mucus plugs
Isthmus: softer and longer (1,7-10cm) lower segment
Cervix: increased vascularity, edema of the entire cervix, hyperplasia of cervical glands. be soft and coloration or stain secrete amount of mucus avoiding the uterus cavity suffer from infection

47. Maternal Physiology

48. Changes of ovary Enlarged Ovulation and new follicle is stopped.
Luteum produces E and P from 7 weeks of pregnancy, but start to atrophy after 10 weeks of pregnancy, the fuction is replaced by placenta

49. Fallopian tubes: is prolonged but not hypertrophy
Vagina: dilated and soft , violet coloration, desquamation of epithelium with more glycogen acidity pH (anti- bacteria)
Vulva: pigmentation
Ligaments: relaxed

50. breasts
An increase in size and a nodular sensation due to the hypertrophy of the mammary alveoli, the nipples soon become larger, more deeply pigmented and more erectile. Scattered around the areola are some roundish nodules called Montgomery tubercles which result from the hypertrophy of the sebaceous glands

51. Changes of the circulation
Heart border: become enlargement, move upward, hypertrophy of cardiac muscle
Heart rate: increased beat per min at the late pregnancy
Heart volume: increased 10% at the late pregancy
The growing uterus pushes the diaphragm upward, with the result that the heart is displaced to the left, upward and somewhat in the direction of the anterior chest wall. A certain degree of rotation is believed to take place. The capacity increases by 10%, the heart rate increases by 10-15bpm

52. Cardiac output Very important for fetal growth and development
Increase by 30%, from 10weeks and up to the peak at 32 weeks
80ml/bp and keeps the level to the term pregnancy

53. Blood pressure changes due to pregancy
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 demonstrable in later months of pregnancy because of the disturbance of vein reflux
Supine hypotension syndrom: supine position for a long time---inferior vene cava compressed---back volume ---output ---Bp ---cm. of hypotension

54. Changes of blood system
Volume: increased (30-45%) from 6-8 weeks , peak at 32-34weeks, about 1500ml (including plasma 1000ml and 500ml erythrocytes---hemodilution)

55. Changes of blood component
Red cell
Hb decreasd 110g/L
Hct : 38%--31%
WBC:
Slightly increase
neutrophilic granulocyte increased
Coagulating power of blood:
Albumin: 35g/L

56. Urinary system Kidney Ureter: dilated ( P ) Bladder
Renal plasma flow (RFP): 35%
Glomerular filtration rate (GFR):
Ureter: dilated ( P )
Bladder
Frequent micturation
Both RPF, and GFR increase by about 35% and 50% respectively, the metabolites of the gravida/fetus can be excreted. Under the influence of progesterone, a condition of atonia in relaxation or loss of irritability not only of uterus, but also of the ureters, large bowel and bile ducts---dilatation of ureters and renal pelvis associated with stasis of urine---acute nephropyelitis especially in the right side

57. Respiratory system R rate : slightly Vital capacity: no change
Tidal volume: 40%
Functional residual capacity:
O2 consumption: 20%

58. Gastrointestinal system
Gastric emptying time is prolonged nausea
The motility of large bowel is diminished constipation
Liver function: unchanged
Digestive sys: estrogen---gingiva---hyperplasia progesterone---atonia of stomach and bowel---heart burn, vomit, constipation

59. skin
The pigmentation of the areola, linea alba, vulva, occasionally irregularly shaped, brownish patches of varying size appear on the face and neck, the cloasma or the mask of pregnancy, which fortunately usually disappears after delivery
During late months of pregnancy, reddish, slightly depressed streaks often develop in the skin of abdomen, and sometimes also in the skin covering the breasts and the thighs.these striae gravidarum occur in about ½ of all pregnancies

60. Endocrine changes Pituitary ( hypertrophy) Thyroid LH/FSH PRL
TSH and ACTH
Thyroid
Enlarged (TSH and HCG )
Thyroxine and TBG free T3 T4 unchanged
Pituitary gland: the anterior lobe hypertrophy
High level of E and P---inhibites Gn releasing
PRL: increases from 7w, peak ante-delivery
Adrenalin cortex: the level cortisol and aldosterone increases by 3 and 4 times respectively
Thyroid gland: the enlargement usually concomitant with normal pregnancy due to hypertrophy of adenomatous tissue, to an increase blood supply and to the formation of new follicles. But most thyoxin is connected with thyroxin binging globulin, so no hyperthyroidism occurs

61. Metabolic changes BMR: mildly rising
Weight: from 13w increases by 350g per week, about 12.5kg during the entire pregnancy
Metabolism of carbohydrate
Fasting-sugar lower due to higher insulin-secretion
Insulin-resistant factors
Fat metabolism: deposit of fat increasing chareterized by a hyperlipemia and a tendency to ketosis

62. Protein metabolism: positive nitrogen balance
Water metabolism: water-retention of about 7L
Mineral metabolism: in the late months of gestation
Calcium and iron supplying---to avoid deficiency of calcium and iron

63. Bone, joint, and ligament
Bone: no changes normally
Joint and ligament: relaxin---loosening of joint and ligaments---the birth canal widened

64. THANKS!