Physiological changes in pregnancy

This slides briefly delivers physiological changes in system wise

1. Physiological changes during pregnancy D. Kavitha M.Sc (N), M.Sc ( Psy ),DHHM,BSAM, Ph.D scholar Lecturer in OG MTPGRI&HS Pondicherry

2. 2 Maternal physiologic adjustment to pregnancy are designed to support the requirements of fetal homeostasis and growth. This is accomplished by remodeling maternal systems: To deliver energy and growth substrates to the fetus To remove inappropriate heat and waste products Those maternal adaptation maintain a healthy environment for the fetus.

3. Body system alterations Cardiovascular Hematological Respiratory Genitourinary Gastrointestinal Immunological Musculoskeletal Endocrine

4. Cardiovascular system Cardiovascular adaptation affects all organ systems. Cardiovascular anatomy and physiology changes to accommodate increasing maternal and fetal circulatory needs.

5. Heart Anatomic changes: Heart is enlarged, displaced upward and rotates to the left. PMI (point of maximal impulse) shifts to 4 th intercostal space and closer to the midclavicular line.

6. Heart sounds and rate Audible splitting of S1 and S2; S 3 becomes audible. Benign systolic murmurs are common. Heart rate increases 15-20 beats as pregnancy progresses

7. Cardiac output Defined as the amount of blood pumped from the left ventricle into the aorta each minute. (heart rate x stroke volume = CO) In pregnancy increased by 40% by 36-38 wks. Influenced by: Blood volume Stroke volume Heart rate

8. Labor TIME FRAME CARDIAC OUTPUT CHANGE 1 st Trimester Increased 22% > pre-pregnancy values due to increased stroke volume 3 rd Trimester Increased 30-50% > pre-pregnancy values due to increased heart rate and stroke Labour Increased 12%-49% during 1 st and 2 nd stage due to shunting of blood from uterus to maternal circulation with pushing

9. Blood pressure Due to decreased systemic vascular resistance, blood pressure is lower at end of 1 st trimester and throughout 2 nd , returning to baseline in 3 rd trimester. Also affected by renin-angiotensin-aldosterone system from kidneys.

10. Hematological changes Increase in WBCs and RBCs. Increase blood volume for uterus, fetus and increased perfusion of other organs, especially kidneys. Increased plasma volume ratio to RBC volume leads to hemodilution .

11. Respiratory changes Anatomic changes: Diaphragm elevation Chest expansion Capillary dilation early in pregnancy causes Engorgement of entire tract from nares to bronchi Voice changes

12. Respiratory changes - cont Physiological changes: Increased need for oxygen Improved oxygen delivery Hyperventilation Compensatory respiratory alkalosis

13. Genital changes The body of the uterus Height and weight (hyperplasia) the height increases from 7.5 cm to 35cm the weight increases from 50g to 1000g at term Uterine ligaments show hypertrophy Dextro -rotation the uterus is tilted and twisted to the right in 80% of cases Lower uterine segment (LUS) the LUS is formed from the isthmus formed from the 4 th month to reach 10 cm at full term

14. Genital changes The cervix - edema and congestion, and becomes soft - mucus plug (operculum): cervical mucus closing the cervical canal - increased secretion from its glands The vulva shows increased vascularity and varicosities

15. The cervix - edema and congestion, and becomes soft - mucus plug (operculum): cervical mucus closing the cervical canal - increased secretion from its glands The vulva shows increased vascularity and varicosities

16. Genital changes The vagina - shows increased vascularity soft, moist and bluish - distention of vagina at birth The ovary shows increased vascularity and size one ovary contains the corpus luteum Pelvic ligaments - relaxation of the ligaments - relaxation of the pelvic joints - the pelvis become more mobile and increases in capacity

17. Breast changes Increased size and vascularity  warm, tense and tender Increased pigmentation of the nipple and areola Secondary areola appear (light pigmentation around the 1ry areola) Montgomery tubercules appear on the areola (dilated sebaceous glands) Colostrum like fluid is expressed at the end of the 3 rd month

18. U rinary changes Kidneys – increase in size and GFR. Bladder – tone decreases due to progesterone, becomes displaces as uterus grows.

19. Urinary changes cont Urine flow accumulates and slows. Increased renal excretion of BUN, creatinine and glucose. Decreased serum BUN, creatinine and glucose. Decreased tubular reabsorption of glucose. Increased tubular reabsoption of sodium.

20. Gastro intestinal changes Increased salivation ( ptyalism ) Taste is often altered very early in pregnancy,Increase appetite & thirst frequent small snacks Heart burn (reflux oesophagitis ) , relaxation of the cardiac sphincter due to progesterone and relaxin Emesis gravidarum , morning sickness in 50 % Decreased gastric acidity , which interfere with iron absorption Constipation - reduced gut motility due to progesterone, increased water and salt absorption

21. Gastro intestinal changes Esophagus, stomach and intestines move as uterus grows. Round ligament stretches as uterus expands. Gallbladder –decrease tone and motility combined with increased emptying time can cause increased risk of gallstones.

22. Liver - Hepatic synthesis of albumin, plasma globulin and fibrinogen increases - Total hepatic synthesis of globulin increases stimulated by estrogen - Hormone-binding globulins rise - gall bladder increases in size and empties more slowly - relaxation of gall bladder increases the tendency of stone formation - cholestasis is almost physiological - secretion of bile is unchanged

23. Hematological changes T and B lymphocyte counts do not change but their function is suppressed ( women become more susceptible to viral infections, malaria and leprosy) Platelet count and platelet volume are largely unchanged

24. Endocrine changes Pituitary - anterior pituitary increases in size and activity - posterior pituitary releases oxytocin on the onset of labor Thyroid - increases in size and activity: physiological goiter - most pregnant women are euthyroid - thyroid binding globulin concentrations double (not other thyroid binding proteins) - total T3, T4 are increased (not the free T3 ,T4) Parathyroid increases in size and activity to regulate calcium metabolism

25. Adrenals - increases in size and activity - total cortisol is increased (free cortisol unchanged) Placental hormones Progesterone - produced by the corpus luteum - levels rise steadily during pregnancy, output reaches 250mg/day - actions: colon activity reduced, nausea, constipation reduced bladder and ureteric tone diastolic pressure reduced, venous dilatation raises temperature

26. Placental hormones Oestrogens - source: ovary in early pregnancy later, oestrone and oestradiol produced by the placenta increased a hundredfold oestriol produced by the placenta and fetal adrenals increased thousand fold - levels: output of oestrogens reaches a maximum of at least 30-40mg/day oestriol accounts 85% levels increase up to term

27. Placental hormones Oestrogens - possible actions: 1- induce growth of uterus and control its function 2- responsible for the development of breasts ( with progesterone) 3- alter chemical constitution of connective tissue, become more pliable 4- cause water retention 5- reduce sodium excretion

28. Metabolic changes General metabolism increased due to needs of growing fetus BMR increased to extent of 30% higher Protein metabolism Positive nitrogenous balance throughout pregnancy Anabolism! Carbohydrate metabolism Insulin secretion increased Sensitivity of insulin receptor reduced To ensure continuous supply of glucose to fetus

29. Metabolic changes Fat metabolism 3-4kg fat stored at abdomen, breast, hips and thighs. Lipid metabolism HDL level increased by 15% LDL utilized for placental steroid synthesis. Iron metabolism Pregnancy is an iron deficiency state Absorption from gut is increased but lost along the routes, to placenta and during delivery. Serum iron and ferritin will fall if supplementation is not given.

30. Musculoskeletal changes Increased lumbar lordosis Relaxation of pelvic joints and ligaments due to progesterone and relaxin

31. Skin changes Pigmentation due to increased melanocyte stimulating hormone: - linea nigra : pigmentation of the linea alba, more marked below the umbilicus - chloasma gravidarum : Butterfly pigmentation of the face (mask of pregnancy) Striae gravidarum - stretch of the abdominal wall rupture of the subcutaneous elastic fibers pink lines in flanks - become white after labor

32. Weight increases There is an increase weight of approximately 12.5 Kg at term The main increase occurs in the 2 nd half of the pregnancy, 0.5 Kg/week Causes: growth of the conceptus enlargement of the maternal organs maternal storage of fat increase in maternal blood and interstitial fluid

33. Thank You