26-Jun-16Physiological Changes of Pregnancy1 Physiological Changes During Pregnancy

26-Jun-16Physiological Changes of Pregnancy2 Maturation of Ovum  Primary oocyte stage Ovum still in ovary Nucleus divide by meiosis 23 pairs of chromosome divide  Half remain in primary oocyte  The other half go to 1 st polar body  1 st polar body expelled

26-Jun-16Physiological Changes of Pregnancy3 Maturation of Ovum  Primary oocyte then become Secondary oocyte Has 23 unpaired chromosome Ovulation occurs

26-Jun-16Physiological Changes of Pregnancy4 Fertilization  Transportation of sperms aided by Prostaglandins in seminal fluid Oxytocin released by female pituitary  Fertilization takes place in Ampulla of fallopian tube Fallopian tube Uterus Ovary Sperms Ampulla

26-Jun-16Physiological Changes of Pregnancy5 Fertilization  Entry of sperm into ovum Oocyte divide to form mature ovum Second polar body is expelled  Form female pronucleus 23 chromosomes one of which is X

26-Jun-16Physiological Changes of Pregnancy6 Fertilization  The sperm head forms Male pronucleus  The 23 unpaired chromosome From male & female pronucleus  Align themselves  Reform complete complement of 46 chromosome

26-Jun-16Physiological Changes of Pregnancy7 Implantation  After reaching the uterus Developing blastocyst remain in  Uterus cavity for 1 – 3 days  Implantation results from Trophoblast cells action Guyton

26-Jun-16Physiological Changes of Pregnancy8 Implantation  Trophoblast cells Develop over the surface of blastocyst Secrete proteolytic enzymes  Digest adjacent uterine endometrial tissue Guyton

26-Jun-16Physiological Changes of Pregnancy9 Placenta

26-Jun-16Physiological Changes of Pregnancy10 Formation of Placenta  Blastocysts, adjacent cells from blastocyst and endometrium Proliferate to form placenta

26-Jun-16Physiological Changes of Pregnancy11 Formation of Placenta  Trophoblastic cords from blastocyst Attach to uterus Blood capillaries grow into cords Blood sinuses supplied with blood from mother  Develop around the cord

26-Jun-16Physiological Changes of Pregnancy12 Formation of Placenta  Trophoblastic cells Send out more projections Become placental villi

26-Jun-16Physiological Changes of Pregnancy13 Function of Placenta  Foetal blood flow through Umbilical arteries Capillaries of villi Back through single umbilical vein

26-Jun-16Physiological Changes of Pregnancy14 Function of Placenta  Maternal blood flows through Uterine arteries Into large maternal sinuses Back into uterine veins  Total surface area of all villi Small compared to that of pulmonary membrane

26-Jun-16Physiological Changes of Pregnancy15 Function of Placenta  Placenta provides for Diffusion of nutrients, oxygen Diffusion of nutrients, oxygen  From mother’s blood into foetal blood Diffusion of excretory products Diffusion of excretory products  From foetal circulation into mother’s blood

26-Jun-16Physiological Changes of Pregnancy16 Hormonal Functions of Placenta  Placenta secretes Human chorionic gonadotropin (hCG) Human chorionic gonadotropin (hCG) Oestrogens & progestrons Oestrogens & progestrons Human chorionic somatomammotropin (hCS) Human chorionic somatomammotropin (hCS)

26-Jun-16Physiological Changes of Pregnancy17 Human Chorionic Gonadotropin  Secreted by syncytiotrophobast cells Same molecular structure as LH Same molecular structure as LH Prevent involution of CL Prevent involution of CL Cause CL to secrete Cause CL to secrete  Oestrogens & progestrons Oestrogen & progestrone Oestrogen & progestrone  Pr event menstruation  Cause endometrium to continue to grow CL involutes after 13 th to 14h weeks of pregnancy CL involutes after 13 th to 14h weeks of pregnancy

26-Jun-16Physiological Changes of Pregnancy18 Human Chorionic Gonadotropin hCG effects on the foetus hCG effects on the foetus  Exerts an interstitial cell-stimulating effects on testes of male fetus Production of testosterone Production of testosterone Testosterone cause descent of testes into scrotum Testosterone cause descent of testes into scrotum

26-Jun-16Physiological Changes of Pregnancy19 Secretion of Oestrogen  Produced by syncytiotrophoblasts  From androgenic steroids from fetal & maternal adrenal glands Dehydroepiandrosterone (DHEA) Dehydroepiandrosterone (DHEA) 16- Dehydroepiandrosterone (16-DHEA) 16- Dehydroepiandrosterone (16-DHEA)  Trophoblast cells convert DHEA, 16- DHEA into Estradiol, estrone, estriol Estradiol, estrone, estriol

26-Jun-16Physiological Changes of Pregnancy20 Functions of estrogens in pregnancy  Exert proliferative function Reproductive organs of mother Reproductive organs of mother  Large quantities of oestrogen cause Enlargement of mothers uterus Enlargement of mothers uterus Enlargement of mothers breasts Enlargement of mothers breasts  Growth of breast ducts Enlargement of mothers external genitalia Enlargement of mothers external genitalia Relaxation of pelvic ligaments Relaxation of pelvic ligaments

26-Jun-16Physiological Changes of Pregnancy21 Secretion of Progesterons by placenta  Initially secreted by CL  Later by placenta  Progesterone Causes development of decidual cells (in endometrium) Causes development of decidual cells (in endometrium)  Important for nutrition of embryo Decrease contractility of pregnant uterus Decrease contractility of pregnant uterus  Prevent abortion Contribute to development of the conceptus Contribute to development of the conceptus

26-Jun-16Physiological Changes of Pregnancy22 Human chorionic somatomammotropin (hCS)  Human placental lactogen (HPL) Promotes lactation in experimental animals Promotes lactation in experimental animals  Has chemical structure similar to GH  Has action similar to GH But weaker But weaker

26-Jun-16Physiological Changes of Pregnancy23 Human chorionic somatomammotropin (hCS)  Decrease insulin sensitivity ↓glucose utilization by the mother ↓glucose utilization by the mother Makes glucose available to foetus Makes glucose available to foetus  Promote release of FFA From fat stores of mother From fat stores of mother Provide alternate energy source for the mother Provide alternate energy source for the mother

26-Jun-16Physiological Changes of Pregnancy24 Endocrine Glands During Pregnancy  Pituitary gland Mother’s pit. Gland enlarges Mother’s pit. Gland enlarges  Increase production of Corticotropin, thyrotropin Corticotropin, thyrotropin Prolactin Prolactin  Secretion of FSH, LH Suppressed because of Suppressed because of  Oestrogen, progestron

26-Jun-16Physiological Changes of Pregnancy25 Adrenal glands  Mother’s Adrenal cortex increase Rate of secretion of glucocorticoids Rate of secretion of glucocorticoids  Mobilize AA from mothers tissue Secretion of aldosterone Secretion of aldosterone  Na +, water retention (also effect of oestrogens)  This can lead to (PIH) pregnancy induced hypertension

26-Jun-16Physiological Changes of Pregnancy26 Thyroid gland  Mother’s thyroid gland enlarge Increase production of thyroxin Increase production of thyroxin  Partly due to thyrotropic effect of hCG  Human chorionic thyropin

26-Jun-16Physiological Changes of Pregnancy27 Parathyroid Gland  Mother’s gland enlarges Especially if there is deficiency of Ca ++ in diet Especially if there is deficiency of Ca ++ in diet  There is increase in secretion of PTH This cause ↑ Ca ++ absorption from mother ’ s bones This cause ↑ Ca ++ absorption from mother ’ s bones

26-Jun-16Physiological Changes of Pregnancy28 Relaxin  Polypeptide hormone Secreted by the CL and placenta Secreted by the CL and placenta Cause relaxation of ligaments Cause relaxation of ligaments  Symphysis pubis (same effects as oestrogen)

26-Jun-16Physiological Changes of Pregnancy29 Mother’s Response to Pregnancy  Due to presence of foetus, excess hormones There is increase in size of various sexual organs There is increase in size of various sexual organs  ↑ in size and wt of uterus (50gm to 1100gm)  Breasts double in size  Vagina enlarges

26-Jun-16Physiological Changes of Pregnancy30 Mother’s Response to Pregnancy  Hormones can cause changes in appearance of pregnant woman Development of oedema Development of oedema Acne Acne Masculine or acromegalic feature Masculine or acromegalic feature

26-Jun-16Physiological Changes of Pregnancy31 Weight gain in Pregnancy  Average wt gain during normal pregnancy about 24 lb (10.9 kg) Foetus=7lb (3.2 kg) Foetus=7lb (3.2 kg) Amniotic fluid, placenta, membranes = 4 lb (1.8kg) Amniotic fluid, placenta, membranes = 4 lb (1.8kg)  Uterus=2 lb (0.9 kg)  Breasts = 2lb (0.9 kg)  ECF = 6 lb (2.7 kg)  Fats = 3 lb (1.4 kg)

26-Jun-16Physiological Changes of Pregnancy32 Metabolism During Pregnancy  ↑ in BMR by about 15% Effects of Effects of  Thyroid hormones  Adrenocortical hormones  Sex hormones  hCS causes ↓glucose utilization by mother ↓glucose utilization by mother ↑ fat metabolism ↑ fat metabolism ↑ protein metabolism ↑ protein metabolism

26-Jun-16Physiological Changes of Pregnancy33 CVS  Maternal circulation ↑ Mother’s CO (30% - 40%) ↑ Mother’s CO (30% - 40%)  Blood flow through placenta  Increase mother’s metabolism Blood pressure falls at 27 th week Blood pressure falls at 27 th week  Effects of ↑ progestrone

26-Jun-16Physiological Changes of Pregnancy34 CVS  Blood volume Maternal blood volume increase (30%) due Maternal blood volume increase (30%) due  Aldosterone  Oestrogen  Fluid retention by kidney  Bone marrow hyperactive Increase production of RBCs Increase production of RBCs At birth, mother has extra 1 -2 Lt of blood At birth, mother has extra 1 -2 Lt of blood

26-Jun-16Physiological Changes of Pregnancy35 Respiratory System  Increase in O 2 consumption (20%) ↑ in BMR ↑ in BMR ↑ in weight ↑ in weight  ↑ in CO 2 production  Minute ventilation increases (50%) Due to effect of progesterone on RC Due to effect of progesterone on RC Arterial PCO 2 decreases Arterial PCO 2 decreases

26-Jun-16Physiological Changes of Pregnancy36 Renal system  GFR increases (50%) due to Increase in ECFV, cortisol Increase in ECFV, cortisol  50% Increase renal tubule reabsorptive capacity Na +, Cl -, water Na +, Cl -, water  Plasma urea, creatinine lowered  Renal threshold of glucose lowered Glucosuria Glucosuria

26-Jun-16Physiological Changes of Pregnancy37 Physiological changes  CVS Blood volume increase by 30% Blood volume increase by 30% Increase in haemopoiesis Increase in haemopoiesis  Effect of relative hypoxia, oestrogen CO increases 30 – 40% CO increases 30 – 40%  Effects of Aldosterone

26-Jun-16Physiological Changes of Pregnancy38 Lactation

26-Jun-16Physiological Changes of Pregnancy39 Breast Development  Growth of ductal system Stimulated by Stimulated by  Oestrogens  Also GH, prolactin, glucocorticoids  Development of lobule – alveolar system Effects of progestrone, oestrogens Effects of progestrone, oestrogens

26-Jun-16Physiological Changes of Pregnancy40 Milk Sysnthesis  During pregnancy Prolactin, progestrone, hCS Prolactin, progestrone, hCS  Stimulate breast growth  Capacity to produce milk  Lactation Actual milk release Actual milk release Is inhibited by high levels Is inhibited by high levels  Oestrogens  progestrone

26-Jun-16Physiological Changes of Pregnancy41 Milk Sysnthesis  After delivery of placenta Levels of progestrone & oestrogens fall Levels of progestrone & oestrogens fall Inhibition is removed Inhibition is removed

26-Jun-16Physiological Changes of Pregnancy42 Lactation  Hormones supporting lactation Growth hormone Growth hormone Glucocorticoids Glucocorticoids  ↑ glucose in milk PTH PTH  ↑ Ca ++ in milk Insulin Insulin  Necessary to provide AA, Fatty acids, calcium, glucose AA, Fatty acids, calcium, glucose

26-Jun-16Physiological Changes of Pregnancy43 Lactation  Maintenance of milk secretion Action of ant. & post pituitary Action of ant. & post pituitary Interaction of mother & infant Interaction of mother & infant

26-Jun-16Physiological Changes of Pregnancy44 Suckling  Stimulate pathways Suppress dopamine in hypothalamus Suppress dopamine in hypothalamus  This leads to production of Prolactin, necessary for milk synthesis Prolactin, necessary for milk synthesis

26-Jun-16Physiological Changes of Pregnancy45 Suckling  Also stimulate Production of oxytocin Production of oxytocin Promote contraction of mammary myoepithelial cells Promote contraction of mammary myoepithelial cells Milk ejection Milk ejection