Maternal Response to Pregnancy PDF

Maternal Response to Pregnancy Dr Lamis Kaddam Ph D Physioplogy 1  Objectives 1- Outline maternal response to pregnancyincluding: Cardio vascular system Renal system Respiratory system Metabolic rate 2- Demonstrate hormonal changes during pregnancy....

Maternal Response to Pregnancy Dr Lamis Kaddam Ph D Physioplogy 1  Objectives 1- Outline maternal response to pregnancyincluding: Cardio vascular system Renal system Respiratory system Metabolic rate 2- Demonstrate hormonal changes during pregnancy. Dr Lamis Kaddam Ph D Physioplogy 2  Response of the Mother’s Body to Pregnancy Due to the higher levels of hormones of pregnancy there is the increased size of the various sexual organs; Changes in a pregnant woman’s appearance, edema, acne, and masculine or acromegalic features. Dr Lamis Kaddam Ph D Physioplogy 3  Weight Gain in the Pregnant Woman Is about 11 to 16 Kgm, with most of this gain occurring during the last two trimesters. About 4 kgm fetus and 1.5 Kgm is amniotic fluid, placenta, and fetal membranes Uterus increases about 1 Kgm and the breasts another 1 Kgm. About 2 Kgm is extra fluid in the blood & extracellular fluid; which is excreted the first few days after birth The remaining 1 to 8 Kgm is generally fat accumulation. Dr Lamis Kaddam Ph D Physioplogy 4  Metabolism During Pregnancy Thyroxine, adrenocortical hormones & sex hormones are increased during pregnancy ⇛⇛⇛ basal metabolic rate BMR increases about 15 % during the latter half of pregnancy. She frequently has sensations of becoming overheated. Due to extra load she is carrying, Extra energy, must be expended for muscle activity. Dr Lamis Kaddam Ph D Physioplogy 5 Changes in the Maternal Circulatory System During Pregnancy Blood Flow Through the Placenta would increase Peripheral resistance would decrease This flow, plus the general increase in the mother’s metabolism, increases the mother’s cardiac output to 30 to 40 % above normal by the 27th week of pregnancy. COP falls to only a little above normal during the last 8 weeks of pregnancy,- or unexplained reasons-. Dr Lamis Kaddam Ph D Physioplogy 6  Maternal Blood Volume Increases During Pregnancy about 30 % above normal. Increased fluid retention by the kidneys; by aldosterone and estrogens. Extra RBCs ; by the bone marrow -At the time of birth, mother has about 1 to 2 litres of extra blood in her circulatory system. During delivery of the baby; only about 1/4 of this amount is normally lost through bleeding, allowing a considerable safety factor for the mother. Dr Lamis Kaddam Ph D Physioplogy 7  Maternal Respiration Increases During Pregnancy. Pregnant woman minute ventilation is ⇑⇑: because of increased BMR because of her greater size. high levels of progesterone increases the sensitivity of the respiratory center to CO2 The growing uterus presses upward against the abdominal contents. Dr Lamis Kaddam Ph D Physioplogy 8  Changes in Lung volumes During Pregnancy. Decreased functional residual capacity due to a decrease of both expiratory reserve volume and residual volume Primarily the result of upward displacement of the maternal diaphragm Tidal volume increase by 40% Resulting to hyperventilation and hypocapnia Dr Lamis Kaddam Ph D Physioplogy 9  Maternal Kidney Function During pregnancy The rate of urine formation by a pregnant woman is usually slightly increased because of increased fluid intake and load of excretory products. special alterations of kidney function occur. First, the renal tubules’ reabsorptive capacity is increased by steroid hormones. Second, the RBF & GFR increase as a result of renal vasodilation. Due to vasodilation in pregnancy (nitric oxide) or the ovarian hormone relaxin. The increased GFR likely occurs, at least in part, as a compensation for increased tubular reabsorption of salt and water. Thus, the normal pregnant woman ordinarily accumulates reasonable percentage of extra water and salt. Dr Lamis Kaddam Ph D Physioplogy 10 Amniotic Fluid and Its Formation 0.5 -1 litre Is derived from renal excretion- large portion of the fluid by the fetus- & a certain amount of absorption occurs by way of the gastrointestinal tract and lungs of the fetus. Some of the fluid is formed and absorbed directly through the amniotic membranes. Dr Lamis Kaddam Ph D Physioplogy 11 HORMONAL FACTORS IN PREGNANCY Dr Lamis Kaddam Ph D Physioplogy 12 Activities of other End. Glands 1. Ant. Pituitary: ↑ ACTH, TSH & PRL + ↓ FSH & LH. 2. Adrenal Cortex: ↑ Cortisol → mobilizes mothers a.a. to fetus ↑ Aldosterone → salt & water retention → hypertension & edema of pregnancy 3. Thyroid & parathyroid: ↑ THs by placental hCG. ↑ PTH → mobilizes Ca from mother bones 13 Dr Lamis Kaddam Ph D Physioplogy  Human Chorionic Gonadotropin HCG, is secreted by the syncytial trophoplast, 8 to 9 days after ovulation, reach a maximum at about 10 to 12 weeks decreases to a lower value by 16 to 20 weeks. HCG conserves the corpus luteum to secrete even larger quantities of progesterone and oestrogen for the next few months. HCG stimulates the interstitial cells of Leydig on the testes of the male fetus, resulting in the production of testosterone until the time of birth. It causes the fetus to grow male sex organs It causes the testes to descend into the scrotum Dr Lamis Kaddam Ph D Physioplogy 14 Estrogen In Pregnancy The estrogens secreted by the placenta -androgenic steroid compounds- are formed both in the mother’s adrenal glands and in the adrenal glands of the fetus. During pregnancy, the extreme quantities of estrogens cause: 1enlargement of the mother’s uterus & breasts (ducts) and external genitalia. The estrogens also relax the pelvic ligaments of the mother. Dr Lamis Kaddam Ph D Physioplogy 15  SECRETION OF PROGESTERONE BY THE PLACENTA Is secreted in moderate quantities by the corpus luteum at the beginning of pregnancy, then in tremendous quantities by the placenta, Progesterone causes decidual cells to develop in the uterine endometrium; nutritive. Progesterone decreases the contractility of the pregnant uterus, preventing abortion. It specifically increases the secretions of the mother’s fallopian tubes and uterus to provide appropriate nutritive matter for the developing morula. Progesterone affects cell cleavage in the early developing embryo. The progesterone prepare the mother’s breasts for lactation. Dr Lamis Kaddam Ph D Physioplogy 16  HUMAN CHORIONIC SOMATOMAMMOTROPIN HPL Secreted by the placenta at about the 5th week of pregnancy. It has several possible important effects. causes at least partial development of the animal’s breasts anabolic effect similar to those of growth hormone, causes decreased insulin sensitivity and decreased utilization of glucose in the mother, glucose is the major substrate used by the fetus. Promotes the release of free fatty acids from the fat stores of the mother. Dr Lamis Kaddam Ph D Physioplogy 17 “Relaxin” It is secreted of by the Ovaries and Placenta. It softens the cervix of the pregnant woman at the time of delivery. It is also thought to serve as a VASODILATOR, contributing to increased blood flow in various tissues, including the kidneys, and increasing VR and COP in pregnancy. Dr Lamis Kaddam Ph D Physioplogy 18 Test Your Understanding The placenta produces both: A. androgens and estrogens. B. estrogen and progesterone. C. progesterone and prolactin. D. Prolactin and FSH. 19 Dr Lamis Kaddam Ph D Physioplogy Q. Secretion of estriol during pregnancy A) is dependent on both a viable fetus and a functioning placenta B) is largely produced by the maternal ovaries C) is not dependent on a viable ovaries D) is lower than the secretion rate of estriol is non pregnancy body Dr Lamis Kaddam Ph D Physioplogy 20 QUESTION Which of the following is increased in pregnancy? a) FRC b) ERV c) RV d) TV Dr Lamis Kaddam Ph D Physioplogy 21 End of the lecture References: 1. Human Physiology, 14th ed. Stuart Ira Fox, 2016, Ch. 20, pp 728-732. 737-738 2. Guyton & Hall Textbook of Medical Physiology, 13th ed., 2016 Ch. 83, pp 1055-62. 3. Web: https://www.khanacademy.org/test- prep/nclex-rn/rn-reproductive-system- physiology/rn-pregnancy/a/physiology-of- pregnancy ‫مع تمنياتي للجميع بالتوفيق والتفوق والنجاح بإذن هللا‬ 22 Dr Lamis Kaddam Ph D Physioplogy