Pregnancy

1. Pregnancy Assoc. prof. Edyta Mądry MD PhD Poznań University of Medical Sciences

2. PREGNANCY Edyta Mądry MD, PhD Department of Physiology Medical University Poznań

3. PregnancyDefinitionThe period from conception to birth.

4. Conception • Conception means a woman's egg has been fertilized by a man's sperm.

5. A secondary oocyte can be fertilized for about 24 hours after ovulation Sperm remain viable for up to 72 hours within the female reproductive tract ⃰Conception

6. Fertilization usually takes place in the outer one-third of the uterine tube (ampulla of oviduct), but can ocasionaly takeplace in the abdominal cavity cervics of uterus (ectopic pregnancy) Sperm swim up the female reproductive tract, aided by muscular contractions of the uterus stimulated by prostaglandins in the semen. ⃰Fertilization

8. How does it start? • Sperm reach ovum and cluster around it

9. Only one sperm is allowed to penetrate egg

10. Assumption: Fertilized 14 days after the first day of LNMP Gives birth 38 weeks after fertilization (+ or - 2 weeks) ⃰Gestation Gestation in singleton pregnancies lasts an average of 40 weeks (280 days) from the first day of the last normalmenstrual period (LNMP). 10 lunar months = 9 calendar months = 280 days (+ or – 2 weeks)

11. ⃰How to calculate the time of birthNaegele's rule 1. Determine first day of LNMP 2. Add one year 3. Subtract three months 4. Add seven days For example: first day of LNMP April 21st, 2015 Resulting data of estimated data of birth : January 28 , 2016 (+ or – 2 weeks )

12. Fertilization • 1 Oocyte • 300 Million Sperm • 24 hours postovulation • size: 0.1 - 0.15 mm

13. Fertilization When the sperm penetrates the egg, the egg immediately releases a chemicals creating a hard “shell” around it to keep all other sperm out and prevent polyspermy

14. Fertilization • FERTILIZED EGG = ZYGOTE • The fertilization process takes about 24 hours. • It takes about ten hours to navigate the female productive track, moving up the vaginal canal, through the cervix, and into the fallopian tube where fertilization begins.

15. Cleavage • First Cell Division, • Mitotic division • size 0.1 - 0.2 mm • 1.5 - 3 days post-ovulation

16. 2 cell zygote The zygote begins to develop 4 cell zygote

17. Three to four days after fertilization. • morula (mulberry shaped)- about 16 cells • morula leaves the fallopian tube and enters the uterine cavity

18. 8 cell zygote 16 cell morula

19. Early Blastocyst • When zygote divides to 32 cells it becomes known as a blastocyst • size 0.1 - 0.2 mm • 4 days post-ovulation • blastocyst formation • Two cell types are forming: • embryoblast (inner cell mass on the inside of the blastocele) • trophoblast(the cells on the outside of the blastocele).

20. Implantation Begins • Human Chorionic Gonadotropin (hCG)level rise • 0.1 - 0.2 mm • 5 - 6 days post-ovulation • The trophoblast cells secretes an enzyme which erodes the epithelial uterine lining and creates an implantation site for the blastocyst (see slide number 22)

21. The blastocyst embeds into the uterine lining, Blastocyst Uterine lining

22. Implantation • ovary continues producing progesterone • trophoblast cells continue releasing human chorionic gonadotropin (hCG) • Endometrial glands in the uterus enlarge in response to the blastocyst and the implantation site becomes swollen with new capillaries ( see slaids 26 and 27).

23. Implantation

24. Implantation Completed • Placental Circulation System Begins to form • 0.1 - 0.2 mm • 7 - 12 days post-ovulation • Trophoblast cells engulf and destroy cells of the uterine lining creating blood pools, both stimulating new capillaries to grow and foretelling the growth of the placenta.

25. Implantation Completed • The inner cell mass divides, rapidly forming a two-layered disc • The top layer of cellswill become the embryo and amniotic cavity • The lower cells will become the yolk sac.

26. ⃰Inner cell mass forms two cavities: • yolk sac • amniotic cavity • ⃰In humans the yolk sac produces blood cells and future sex cells • The amniotic cavity becomes the cavity in which the embryo floats. • Fluid is produced from fetal urine, and secretions from the skin, respiratory tract, and amniotic membranes.

28. Symptoms of early pregnancy • Food cravings or aversions • Smell sensitivity • Heartburn • Missed Period • Morning Sickness • Constipation • Mood Swings/ Irritability • Higher body temperature • Low Back Pain • Tender breast • Bloating / Weight Gain • Fatigue

29. Four Weeks After the cluster of cells attaches to the womb it is called an embryo. .

30. Day 24 Day 22

31. Day 28 Day 26

32. At the end of 4 weeks: • Embryo is 1/4 inch in length • Heart, digestive system, backbone and spinal cord begin to form • Placenta (sometimes called "afterbirth") begins developing

33. At the end of 8 weeks: • Embryo is 1 1/8 inches in length • Eyes, nose, lips, tongue, ears and teeth are forming • Penis begins to appear in boys • Embryo is moving, although the mother can not yet feel movement

34. At the end of 12 weeks: Fetus is 2 1/2 to 3 inches long Weight is about 1/2 to 1 ounce Nails start to develop and earlobes are formed Arms, hands, fingers, legs, feet and toes are fully formed Eyes are almost fully developed By this stage, a fetus has developed most of his/her organs and tissues

35. At the end of 4 months: • Fetus is 6 1/2 to 7 inches long • Weight is about 6 to 7 ounces • Fetus is developing reflexes such as sucking and swallowing. • Fingers and toes are well defined • Sex is identifiable

36. At the end of 5 months: • Fetus is 8 to 10 inches long • Weight is about 1 pound • Hair begins to grow on his/her head • Soft woolly hair called lanugo covers fetus body Mother begins to feel fetal movement

37. At the end of 6 months: • Fetus is 11 to 14 inches long • Weight is about 1 3/4 to 2 pounds • Eyelids begin to part and eyes open occasionally for short periods of time • Fetus is able to hiccup

38. At the end of 7 months: • Fetus is 14 to 16 inches long • Weight is about 2 1/2 to 3 1/2 Pounds • Fat layers are forming • If born at this time, he/she will be considered a premature baby and require special care

39. At the end of 8 months: • Fetus is 16 1/2 to 18 inches long • Weight is about 4 to 6 pounds • Overall growth is rapid this month • Tremendous brain growth occurs • Most body organs are now developed with the exception of the lungs • Movements or "kicks" are strong enough to be visible from the outside

40. At the end of 9 months: • Fetus is 19 to 20 inches long • Weight is about 7 to 7 ½ pounds • The lungs are mature • Baby is now fully developed and can survive outside the mother's body • He/she settles down lower in the abdomen in preparation for birth and may seem less active

41. Labor (parturition)- Stage one • the period from the onset of true labor contractions until the cervix is completely dilated at 10 cm. • The uterine contractions cause the cervix to dilate, and the amniotic sac may rupture. • Usually lasts 6 – 24 hours depending on the number of previous deliveries.

44. Stage 2 • Period from maximal cervical dilation until the birth of the baby • Lasts minutes to an hour • Contractions become • more intense and frequent.

45. Stage 3 • The expulsion of the placenta • Usually occurs within 15 minutes after the birth of the baby, but can range from 5 to 60 minutes.

47. ⃰Placenta • 10-12 weeks is the period of placenta formation • Trophoblast cells use same molecular mechanisms as tumors, but are highly regulated and controlled

48. Placenta • FETAL SIDE • MATERNAL SIDE • They provide… • protection • nutrition • respiration • excretion • hormone production

49. ⃰Functions of Placenta • Exchange of gases between fetus and mother • Delivery of nutrients from mother to fetus • Delivery of antibodies from mother to fetus • Removal of fetus waste • Secretion of hormons including human chorionic gonadotropin ( hCG), progesterone, estrogen, and human chorinic somatotropin (hCS)

50. Placental barrier • Maternal and fetal blood do not mix- “placental barrier”