Normal pregnancy and birth defects

1. HuWenSheng Women’s Hospital School of Medicine Zhejiang University Normal pregnancy and birth defects

2. Normal Pregnancy-- Terminology • 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. Part I Physiology of Pregnancy

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

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

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

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

8. 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)

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

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

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

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

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

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

19. Amniotic fliud • Absord • Fetal membrane • Umbilical cord • Fetal skin • Fetal drinking • Feature 1000-1500ml at 36th-38th week (peak), transparent → slightly turbid

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

21. 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

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

23. 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

24. 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

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

26. 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

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

28. 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

29. Part Ⅱ Diagnoses of Pregnancy

30. Presumptive Symptoms • Amenorrhea: strongly suggestive of pregnancy • Nausea and vomiting • Morning sickness of pregnancy • Results from rapidly rising serum levels of HCG (human chorionic gonadotropin) • Begin at 4 weeks and finish at 12 weeks

31. Probable Signs • Pelvic organs • Chadwick’s sign: vaginal mucosa has bluish color (6-8w) • Goodell’s sign: cyanosis and softening of cervix(6w) • Hegar’s sign: softening between cervix and uterine fundus causes a sensation of separateness between these two structures

32. Presumptive Symptoms • Breast changes • Tenderness and tingling • Enlargement (second month ) • Nodularity (sebaceous glands) • Colostrums secretion (begin after 16 w gestation) • Secondary breasts (Axillary breast tissue often cause a symptomatic lump in the axilla)

33. Breast Enlargement Secondary breast

34. Presumptive Symptoms • Urinary tract • Frequent urination and nocturia • Infection • Quickening • 16-20weeks in primigravidas • 14-16 weeks in multigravidas • Fatigue • one of the earliest symptoms of pregnancy • returns to normal by the 16th to 18th week

35. Presumptive signs • Skin changes • Chloasma:darkening of the skin over forehead, bridge of the nose and cheekbones • Linea nigra: darkening of the nipples and lower midline of abdomen • Stretch marks: separation of the underling collagen tissue and appear as irregular scars • Spider telangiectases

36. Pregnancy test • Urine pregnancy test • Positive around the first missed cycle • Serum pregnancy test: more sensitive • HCG may be detected in maternal serum in 7 days

37. Presumptive signs • Increased basal body temperature (>18 days)

38. Positive manifestations • Ultrasound examination of fetus is one of the most useful technical way • Cervicalmucus examination • Progestational challenge

39. Probable Signs • Abdominal enlargement (the uterus rises out of the pelvis and into the abdomen) • Uterine contractions (Braxton hicks contractions)

40. Ballottement (16-20w) • Uterine souffle It may be more easily accomplished by a vaginal examination

41. Positive manifestations • Fetal heart tone (120-160 BPM) Doppler device can detect at 10 weeks

42. Lie of fetus Longitudinal lie Transverse lie

43. Fetal presentation • Determined by the portion of the fetus that can be felt through the cervix • Cephalic presentations Classified according to the position of the fetal head in relation to the body of the fetus • Breech presentations Classified according to the position the legs and buttocks which present first

44. Fetal presentation • Cephalic presentation Vertex Face Brow

45. Fetal presentation • Breech presentation Complete Incomplete frank

46. 胎先露：最先进入骨盆入口的胎儿部分

47. Fetal position

48. 胎方位：胎儿先露部的指示点与母体骨盆的关系胎方位：胎儿先露部的指示点与母体骨盆的关系 枕左后（LOP) 枕右后（ROP)

49. 胎方位：胎儿先露部的指示点与母体骨盆的关系胎方位：胎儿先露部的指示点与母体骨盆的关系 骶右后（RSP) 肩右前（RScA)