Physiological Changes in Pregnancy PDF

PHYSIOLOGICAL CHANGES IN PREGNANCY Sample Sub-heading PHYSIOLOGICAL CHANGES IN PREGNANCY INTRODUCTION Manipal University College Malaysia 2 CVS CHANGES IN PREGNANCY Primary event is arcuate artery invaded secondarily by trophoblastic tissue → systemic manifestation of vasodilatation →↓ SVR→...

PHYSIOLOGICAL CHANGES IN PREGNANCY Sample Sub-heading PHYSIOLOGICAL CHANGES IN PREGNANCY INTRODUCTION Manipal University College Malaysia 2 CVS CHANGES IN PREGNANCY Primary event is arcuate artery invaded secondarily by trophoblastic tissue → systemic manifestation of vasodilatation →↓ SVR→ Arterial underfilling and venous Manipal University College Malaysia overfilling 3 CVS CHANGES IN PREGNANCY Manipal University College Malaysia 4 CVS CHANGES IN PREGNANCY • Aortocaval compression→ Supine hypotension syndrome • Colloid osmotic pressure/PCWP ↓ → P Edema. • Labor: ↑ CO (15% in 1st stage, 50% in 2nd stage) • Autotransfusion (<500 ml) blood into circulation during contraction • Pain, anxiety ↑ HR, BP • Immediate puerperium: ↑ CO due to relief of Inf cava obst causing ↑ CO by 80% • Change in heart sound, presence systolic murmur • Clinical implications: CCF ↑ Manipal University College Malaysia 5 ECG CHANGES IN PREGNANCY • Atrial and ventricular ectopics • Inverted T wave in lead III • ST-segment depression and T-wave inversion in the inferior and lateral leads • Left-axis shift of QRS Manipal University College Malaysia 6 RESPIRATORY CHANGES IN PREGNANCY • Progressive ↓ in IRV • ↑ minute volume (↑ tidal volume and RR) • Vital capacity remain unchanged • Anatomical changes in airway •Manipal Clinical implication University College Malaysia 7 RESPIRATORY CHANGES IN PREGNANCY • Significant ↑ in oxygen demand during normal pregnancy • State of maternal hyperventilation caused by ↑ minute volume → in ↓ arterial and alveolar CO2 & compensatory ↓ in serum bicarbonate (18–22 mmol/l) → compensated respiratory alkalosis (arterial pH 7.44). • Late pregnancy: Diaphragmatic elevation & change in diaphragmatic excursion Manipal University College Malaysia 8 RESPIRATORY CHANGES IN PREGNANCY • Peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV1) are unaffected. • Subjective feeling of breathlessness without hypoxia which is physiological Manipal University College Malaysia 9 HEMATOLOGICAL CHANGES IN PREGNANCY • Physiological anemia • Hypercoagulative state • ↑ factor VII,VIII, IX,X • ↓ Antithrombin, Protein C, platelet count Manipal University College Malaysia HEMATOLOGICAL CHANGES IN PREGNANCY • 2-3-fold ↑ in the requirement in serum iron, Vit B12 • 10-20 fold ↑ in folate demand • No change in MCV and MCHC • APTT,PT,TT: Normal • D dimer: No value • Venous stasis in the lower limbs is associated with venodilation and decreased flow, which is more marked on the left. This is due to compression of the left iliac vein by the left iliac artery. • On the right, the iliac artery does not cross the vein. Manipal University College Malaysia 11 RENAL CHANGES IN PREGNANCY • Renal blood flow ↑ • Glomerular filtration rate (GFR) ↑ • Fall in SVR due to renin secretion by placenta →PgI2 →vasodilation • Serum creatinine & urea decreases by 20% to 44µmol/L and 3.2 mmol/L. • An increase in urine protein excretion in pregnancy from an upper limit of 150 mg/d to 300 mg/d. • Reabsorption of glucose in kidney is less effective results in excretion of glucose • Smooth muscle relaxation ( by progesterone) and compression of the ureters by the gravid uterus lead to pelvicalyceal dilatation, more prominently on the right than the left causing physiological hydronephrosis Manipal University College Malaysia 12 RENAL CHANGES IN PREGNANCY Clinical implication • Urine dipstick. Glycosuria is common. > 1+ needs evaluation • ↑ incidence of UTI; Asymptomatic bacteriuria (Nitrites, Leucocytes, RBCs presence) • Women with +1 (or >) dipstick indicates positive proteinuria • Normal PCR: 30 mg/mmol • Cr clearance test in DM • eGFR as a marker of renal function is not a sensitive parameter • Creatinine above 90 μmol/L and urea above 4.5 mmol/L are indications for further investigation Manipal University College Malaysia 13 GIT CHANGES IN PREGNANCY • Early pregnancy: Nausea and vomiting is observed in 50-90% cases and resolve in 80% of women by 20 weeks of POG. 0.5-3% will develop HG • This is due to ↑ in level of HCG, E2, Progesterone, Thyroid hormone • Late pregnancy: The stomach is increasingly displaced upwards, leading to increased intra-gastric pressure, ↓oesophageal sphincter tone → symptoms of reflux, nausea and vomiting • Estrogen and progesterone influence abnormalities in gastric neural activity and smooth muscle function, leading to gastric dysrhythmia or gastroparesis. Manipal University College Malaysia 14 GLUCOSE METABOLISM Diabetogenic state • Progressive insulin resistance: Diabetogenic hormones from placenta • Postpartum: Fall in insulin resistance following absence of placenta • Insulin levels are increased in both the fasting and postprandial states in pregnancy. • Fasting glucose levels are decreased Manipal University College Malaysia 15 GLUCOSE METABOLISM • Insulin resistance and relative hypoglycemia results in lipolysis → prefered use fat for fuel • The placenta allows transfer of glucose & AA but is impermeable to large lipids. • If a woman’s endocrine pancreatic function is impaired, and she is unable to overcome the insulin resistance associated with pregnancy results in gestational diabetes Manipal University College Malaysia 16 CHANGES IN THYROID DURING PREGNANCY • TBG is ↑↑ during pregnancy due to E2. • ↑ in TBG rises bound T4,T3 but no change in free T4,T3. • Iodine deficiency observed during pregnancy due to ↑ uptake by thyroid, ↑ renal clearance and ↑ fetal demand after 20 weeks of gestation. • Diffused enlargement of thyroid. Because of sharing similar β unit by HCG and TSH,TSH receptors are prone to stimulated by HCG. Manipal University College Malaysia 17 CHANGES IN PITUITORY GLAND • • • • The pituitary gland enlarges in pregnancy ↑ in E2 → Serum prolactin levels FSH & LH are undetectable during pregnancy. Oxytocin levels ↑ peaks at term. • Hypothalamic ADH ↑ in pregnancy as well as ↑ in vasopressinase, produced by the placenta which enhance the metabolic clearance of ADH and mantains normal level of active ADH. • In conditions of increased placental production of vasopressinase, such as pre-eclampsia or twin pregnancies, a transient diabetes insipidus may develop Manipal University College Malaysia 18 CHANGES IN LIPID & PROTEIN METABOLISM • ↑ in serum cholesterol, Triglyceride, LDL , HDL • Tg provides energy for the mother, while glucose, AA are spared for the foetus. • The increase in LDL cholesterol is important for placental steroidogenesis. Manipal University College Malaysia CHANGES IN CALCIUM METABOLISM • The average foetus requires about 30 g of calcium to maintain its physiological processes. • Most of this calcium is transferred to the foetus during the third trimester • The increase in 1.25-dihydroxyvitamin D is directly responsible for the increase in intestinal calcium absorption. • Increased calcium absorption is also associated with an increase in pregnancy at risk of stones Manipal University College Malaysia 20 MUSCULOSKELETAL CHANGES IN PREGNANCY • Exaggerated lordosis of the lower back, forward flexion of the neck and downward movement of the shoulders • Joint laxity in the anterior and longitudinal ligaments of the lumbar spine • Widening and increased mobility of the sacroiliac joints and pubic symphysis. Manipal University College Malaysia 21 CONCLUSION • Pregnancy is a state of hypervolumic, physiological anemic, hyperdynamic, hypercoagulative, diabetogenic, hyperlipidemic, hypercorticism • This change is adaptation for pregnancy need of mother and fetus Manipal University College Malaysia 22