Physiological changes during pregnancy

physiological changes

1. PHYSIOLOGICAL CHANGES DURING PREGNANCY PRESENTER: Dr. Tanya Das MODERATOR: Dr. Junu Bajracharya

2. GENITAL ORGANS VULVA: VAGINA: Hypertrophied, oedematous, increased vascularity - Jacquemier’s sign Secretion – thin, copious and curdy white pH- 3.5-6 Preponderance of navicular cells in cluster

3. CERVIX: Goodell’s sign Hypertrophy and hyperplasia of cervical glands Mucus plug formation Marked endocervical mucosa proliferation- appears as cervical erosion Secretion is copious and tenacious- physiological leucorrhoea of pregnancy

4. ISTHMUS: Hypertrophy and elongation to about 3 times original length Incorporated into uterine cavity beyond 12 weeks Sphincter action of circular muscles

5. UTERUS: ENLARGEMENT -7.5cm to 35 cm; 60 grams to 1100 grams; 5-10 ml to 5 litres Body of uterus- hypertrophy and hyperplasia of muscles; stretching of muscle fibres Arrangement of muscle fibres :outer longitudinal : inner circular : intermediate- interlacing network of muscles

6. VASCULARITY Uterine artery diameter doubles and blood flow increases to 8 times at 20 weeks of pregnancy Vasodilatation due to estradiol and progesterone SHAPE Pyriform shape in early months, globular at 12 weeks, pyriform again by 28 weeks, spherical by 36 th week Antiverted upto 8 weeks, erect afterwards Dextro -rotated uterus with levo -rotated cervix CONTRACTIONS- Braxton- Hicks

7. FALLOPIAN TUBE AND OVARY: Placed vertical by the side of the uterus Tubes become congested, muscles are hypertrophied Epithelium flattened and pathches of decidual reaction seen Corpus luteum maximum at 8 th week, colloid degeneration occurs at 12 th week

8. BREAST Increased size and vascularity ( hypertrophy and proliferation of ducts and alveoli) Hypertrophy of connective tissue stroma Increased vascularity Increased pigmentation of the nipple and areola Secondary areola appears Montgomery tubercles appear on the areola( dilated sebaceous glands) Secretion( colostrum ) can be squeezed out of breast at about 12 th week

9. CUTANEOUS CHANGES

10. WEIGHT GAIN Total weight gain in pregnancy- averages 11 kg for a healthy women Mainly increases in 2 nd trimester, 0.5kg/week Causes: growing fetus :uterus : accumuation of fat and protein :increased blood volume :increased extracellular fluid

11. New Recommendations for Total and Rate of Weight Gain During Pregnancy, by Prepregnancy BMI(IOM guidelines) Pre-Pregnancy BMI BMI(kg/m2) (WHO) Total weight gain range ( Ibs ) Mean range in ( Ibs / week) underweight <18.5 28-40(12.7-18.14kg) 1-1.3 Normal weight 18.5-24.9 25-35(11.3-15.8kg) 0.8-1 overweight 25.0-29.9 15-25(6.8-11.33kg) 0.5-0.7 Obese (includes all classes) >30.0 11-20(4.9-9.07kg) 0.4-0.6

12. BODY WATER METABOLISM Amount of water retained at term-6.5 ltrs Pregnancy- a state of hypervolemia Retention of Na, K, and water: Changes in osmoregulation Increased estrogen and progesterone Increased renin and angiotensin activity Increased aldosterone Control by AVP

13. HEMATOLOGICAL CHANGES NON-PREGNANT PREGNANCY NEAR TERM TOTAL INCREMENT CHANGE BLOOD VOLUME(ml) 4000 5500 1500 +30-40% PLASMA VOLUME(ml) 2500 3750 1250 +40-50% RED CELL VOLUME(ml) 1400 1750 350 +20-30% TOTAL Hb (gm) 475 560 85 +18-20% HEMATOCRIT 38% 32% diminished

14. PARAMETERS NON-PREGNANT PREGNANCY (near term) CHANGE Total Protein(gm) 180 230 Increased Plasma protein concentration (gm/100ml) 7 6 Decreased Albumin (gm/100ml) 4.3 3 Decreased Globulin (gm/100ml) 2.7 3 Increased Albumin:globulin 1.7:1 1:1 Decreased Plasma Protein changes during pregnancy

15. LEUKOCYTES AND IMMUNE SYSTEM Decrease in humoral and cell-mediated immunity to accommodate foreign semi allogeneic fetus. Neutrophilic leucocytosis ESR increased

16. PARAMETERS NON-PREGNANT PREGNANCY(near term) CHANGE Platelets 1,80,000 Static or 15% reduction of count Fibrinogen(mg%) 200-400 300-600 +50% Fibrinolytic activity depressed Clotting time unaffected ESR 10 mm/hr 40 mm/hr Increased 4X CHANGES IN BLOOD COAGULATION FACTORS

17. CARDIOVASCULAR SYSTEM NON-PREGNANT PREGNANCY (near term) CHANGE CARDIAC OUTPUT (litre/min) 4.5 6.26 +40% STROKE VOLUME (ml) 65 75 +27% HEART RATE (per minute) 70 85 +17% BLOOD PRESSURE Unaffected or mid pregnancy drop of diastolic pressure by 5-10 mmHg VENOUS PRESSURE 8-10cm 20cm +100% COLLOID ONCOTIC PRESSURE(mmHg) 20 18 -14% SYSTEMIC VASCULAR RESISTANCE -21% HEMODYNAMIC CHANGES DURING PREGNANCY

18. ENDOCRINAL CHANGES PITUITARY : Anterior pituitary increases in size and activity Posterior pituitary releases oxytocin at the onset of labour THYROID: Increases in size and activity: physiological goiter Most pregnant women are euthyroid Thyroid binding globulin concentrations double Total T3, T4 are increased( not free T3, T4) PARATHYROID: - Increases in size and activity to regulate calcium homeostasis

19. ADRENALS: Increase in size and activity Total cortisol increased PLACENTAL HORMONES: Progesterone: produced by the corpus luteum , levels rise steadily during pregnancy Oestrogens: ovary in early pregnancy, later oetrone and oestradiol produced by placenta

20. METABOLIC CHANGES CARBOHYDRATE METABOLISM: Pregnancy is hyperlipidemic and glucosuric state Insulin secretion is increased in response to glucose and amino-acids After mid-pregnancy, resistance to insulin develops Insulin resistance is endocrine driven, via increase in cortisol and hPL Plasma glucose concentrations rise, maintained between 4.5-5.5 mmol /L Plasma glucagon level remains unchanged Overall effect is fasting hypoglycemia and post prandial hyperglycemia and hyperinsulinemia

21. NON-PREGNANT PREGNANCY (near term) CHANGE TOTAL LIPID (mg/100ml) 650 1000 +50% LDL and cholesterol (mg/100ml) 180 260 +40% HDL (mg/100ml) 60 70 +15% TRIGLYCERIDES (mg/100ml) 80 160 +50% CHANGES IN LIPID METABOLISM

22. PROTEIN METABOLISM : Positive nitrogen balance At term, fetus and placenta contain about 500 gm chiefly distributed in the uterus, breasts and the maternal blood Blood urea level falls to 15-20 mg% Amino- acids transported across placenta to the fetus

23. IRON METABOLISM : Total iron requirement during pregnancy is estimated approximately 1000mg Serum iron concentration falls, absorption from gut and iron binding capacity increase

24. RESPIRATORY SYSTEM

25. NON-PREGNANT PREGNANCY (NEAR TERM) CHANGE RESPIRATORY RATE 15 15 Unaffected VITAL CAPICITY 3200 3300 Unaffected TIDAL VOLUME(ml) 475 675 +40% RESIDUAL VOLUME( ml) 965 765 -20% TOTAL LUNG CAPICITY 5000 4750 -50% CHANGES IN RESPIRATORY SYSTEM

26. ALIMENTARY SYSTEM Gums become congested and spongy and may bleed to touch Muscle tone and motility is diminished Cardiac sphincter is relaxed and regurgitation of acid gastric content into the oesophagus may produce chemical esophagitis and heart burn Diminished gastric secretion and delayed emptying time of the stomach

27. URINARY SYSTEM Kidneys : increase in size : hydronephrosis : effective renal plasma flow increased Ureter : atony of the ureteric muscles : vesico-ureteric reflux increased : leads to urinary stasis and pyelitis : elongation and kinking of ureter : outward displacement of ureter Bladder : congestion and hypertrophy of muscles : bladder mucosa becomes oedematous

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