PHYSIOLOGICAL change of pregnancy obstetrics

For education

1. PHYSIOLOGICAL CHANGES IN PREGNANCY Presenter : Anshu Maurya Moderator : Dr Mala Shukla Dr Deepika(SR) Dr Aksara (SR)

2. Many gestational changes begin soon after fertilization and continue throughout pregnancy. Most pregnancy related changes are prompted by stimuli provide by fetus and placenta. These changes almost completely return to pre-pregnancy state after delivery and lactation. Some normal physiological changes can unmask or worsen pre-existing diseases.

3. PHYSIOLOGICAL CHANGES IN PREGNANCY Reproductive tract Hematological Cardiovascular Respiratory Renal Endocrine Gastrointestinal Dermatological Musculoskeletal CNS

4. CHANGES IN REORODUCTIVE TRACT Pre-pregnant uterus (70 g , 10 ml) is transformed into thin walled muscular uterus .By term it weighs 1100g and has 5L capacity. Uterine enlargement involves stretching and marked hypertrophy of muscle cells ,fibrous tissue accumulate in external muscular layer. These changes are stimulated by action of estrogen and perhaps progesterone. As pregnancy advances uterus becomes spherical by 12 weeks , subsequently it becomes ovoid, rotates to right side(dextrorotation) caused by rectosigmoid on left side. Infrequent and sporadic uterine contractions appear during second trimester called as Braxton- Hicks contractions. Uterine artery flow increases to 500-750ml/min at 36 week gestation.

5. Vessels supplying uterine corpus widens and enlongates while spiral artery which directly supply the placenta vasodilate and completely loose contracitility . NO, estrogen, progesterone, activin , PIGF and VEGF play a role in angiogenesis and accelerating flow in vessels. As early as 1 month after conception , cervix softens and gain bluish tone due to increased vascularity and edema , alteration in collagen network and hypertrophy and hyperplasia of cervical glands. Pregnancy prompts extension or eversion of proliferating columnar endocervical glands onto ectocervical portio . Endocervical glands hyperplasia and hypersecretory appearance – Arias Stella reaction. Ovulation ceases during pregnancy and maturation of follicles is suspended . Corpus luteum functions maximally during first 6-7 weeks of pregnancy and secretes progesterone. Chadwick sign- bluish discoloration of vagina due to high vascularity and blood flow. Vaginal ph becomes acidic due to increased lactic acid production.

6. HEMATOLOGICAL CHANGES Decreases in: Haemoglobin concentration Haematocrit Platelet count Plasma folate concentration Plasma osmolality Increases in: White cell count Erythrocyte sedimentation rate Fibrinogen Blood volume Spleen size Total iron requirement

7. Pregnancy is a Hypercoagulable state. Vascular stasis and increase in ESR Increased risk for thromboembolic disease Increase in fibrinogen, all coag factors except XIII , XI Fall in protein S and sensitivity to activated protein Haemoglobin conc at term averages 12.5g/dl. A conc less than 11g/dl is considered abnormal. Pregnancy is immunosuppressive state. Expression of special MHC on trophoblast. Suppression of Th1 and T cytotoxic cells. Fall in TNF , IL-2 and interferon alpha

8. CARDIOVASCULAR CHANGES Heart rate increases by 10 beats/min. Stroke volume increases Cardiac output increases Mean arterial pressure decreases Peripheral resistance decreases Left ventricular mass expansion by 30-35 percent by term. SBP and DBP decreases Left ventricular mass increases Heart apex is moved laterally and a large cardiac shillouette in chest radiographs.

9. Increased coronary blood flow. Increased efficiency of cardiac work. Increased RAAS activity. Cardiac natriuretric peptides levels are unchanged. Normal changes in heart sounds during pregnancy: Increased loudness of both s1 and s2 Increased splitting of mitral and tricuspid components of s1 No constant changes in s2 Loud s3 by 20 weeks ’ gestation Most gravidas develop systolic murmur which disappears after delivery Some have a transient diastolic murmur and Some develop continuous murmurs due to increased mammary blood flow

10. Signs & Symptoms of Normal Pregnancy that may Mimic Heart Disease Signs Peripheral edema JVD Symptoms Reduced exercise tolerance Dyspnea Auscultation S3 gallop Systolic ejection murmur Chest x-ray Change in heart position & size Increased vascular markings EKG Nonspecific ST-T wave changes Axis deviation LVH

11. RENAL CHANGES Renin – stimulated by progesterone Also made by placenta Angiotensinogen Angiotensin I Angiotensin II Aldosterone Distal tubule Net absorption of Na + Excretion of K + Water retention: 6-8 liters Hyperfiltration due to- 80 % increase in renal blood flow I ncrease in blood volume Decreased Albumin = lower colloid oncotic pressure

12. OTHER URINARY TRACT CHANGES Ureteral dilation / hydroureter Smooth muscle relaxation Later exacerbation by uterine obstruction Urinary stasis* Dilation of pelves and calyces Increased kidney size. Hyperemia and hyperplasia of baldder muscle. Glucosuria is normal. Haematuria suggest UTI Protienuria >300mg/d is significant.

13. CHANGES IN RESPIRATORY SYSTEM Consumption O2 consumption Increases 20% Despite increase in oxygen requirements, with the increase in Cardiac Output and increase in alveolar ventilation oxygen consumption exceeds the requirements. Therefore, arteriovenous oxygen difference falls and arterial PCO2 falls. RR and TLC is unchanged. Fall in FRC. Rise in IC,TV and Resting minute ventilation.

14. CHANGES IN ENDOCRINE GLANDS Pituitary gland - FSH and LH  - ACTH, Thyrotrophin, melanocyte hormone and prolactin  - Prolactin level  until the 30 th week of pregnancy then more slowly to term. Adrenal gland Total corticosteroids  progressively to term. This will  the tendency of pregnant women to develop abdominal strine , glycosuria and hypertension

15. Thyroid gland - Enlarges during pregnancy, occasionally to twice its normal size. This is mainly due to colloid deposition caused by a lower plasma level of iodine, consequent on the increased ability of the kidneys to excrete during pregnancy. - Oestrogen stimulates or increased secretion of thyroxin in binding globulin. - Both T3 and T4 levels rise. This rise will not indicate hyperthyroidism. Parathyroid gland Parathyroid hormone decrease during early pregnancy and then rise throughout pregnancy

16. CHANGES IN GIT Slowed GI motility Constipation, early satiety Relaxation of LES GERD Nausea / vomiting Often proportional to HCG level Liver / gallbladder Biliary stasis, cholesterol saturation More stones Coagulation factors decreases Increased binding proteins (thyroid, steroid, vitamin D)

17. Digestive system slow due to progesterone Nausea and vomiting Ptyalism: increase salivation Heartburn Hemorrhoids Prolonged gallbladder emptying time may lead to gall stones Bile salt buildup may lead to itching. Displacement of the stomach and intestines Appendix can be displaced to reach the right flank Gastric emptying and intestinal transit times are delayed secondary to hormonal and mechanical factors Pyrosis is common due to the reflux of secretions Vascular swelling of the gums Hemorrhoids due to elevated pressure in veins

18. CHANGES IN SKIN

19. CHANGES IN MSK Musculoskeletalconsequencesthatensueasa result of hormonal changes and weight gain (28lbs ave ) include: – Force across a joint is increased up to two-fold – Joint laxity ( Relaxin ) in the anterior and posterior longitudinal ligaments of the lumbar spine put strain on the lumbar spine. – There is widening and increased mobility of the sacroiliac joints and pubic symphysis to facilitate the baby's passage through the birth canal. – A significant increase in the anterior tilt of the pelvis occurs, with increased use of hip extensor, abductor, and ankle plantar flexor muscles

20. CHANGES IN CNS Decrease in concentration, memory and attention throughout pregnancy. Decreased intraocular pressure and corneal sensitivity. Increased corneal thickness. Transient loss of accommodation. Difficulty with falling asleep , frequent awakening, few hours of night sleep and reduced sleep efficiency.