Introduction Overview many physiologic changes occur in pregnancy help protect mother from hemorrhage help fetus develop properly ensure proper delivery of nutrients to fetus facilitates waste removal from fetus ensures adequate oxygenation of fetus Hematologic Hypercoagulable state synthesis of clotting factors ↑ result of venous stasis secondary to uterine pressure on great veins of lower extremity reduced fibrinolysis Plasma volume ↑ by 30-50% 6-12 weeks of gestation 10-15% 30-34 weeks plateaus or decreases RBC mass ↑ by 30% the increase in plasma volume is larger than the increase in RBC mass this relative difference leads to a dilutional gap of 15-20% which causes physiologic anemia anemia in pregnant women - hemoglobin < 11 g/dL in trimesters 1 and 3 hemoglobin < 10.5 g/dL in trimester 2 lower by 0.8 g/dL in African Americans increased demand for iron and folate Mild neutrophilia result of granulocyte demargination no absolute increase in leukocyte count Slight thrombocytopenia (still within normal limits) Returns to normal 6-8 weeks postpartum Cardiac 1st trimester systemic vascular resistance (SVR) ↓ beginning at 5 weeks total drop 35-40% due to progesterone mediated smooth muscle relaxation heart rate (HR) ↑ cardiac output (CO) ↑ CO = HR x SV (stroke volume) 2nd trimester SVR plateaus HR rises CO ↑ 3rd trimester SVR returns to normal HR peaks CO peaks change in position alters cardiac parameters supine positioning CO ↓ SV ↓ HR ↑ changes due to compression of aorta/vena cava by gravid uterus left lateral decubitus position alleviates these stresses Flow changes ↑ S2 split with inspiration distended neck veins systolic ejection murmor diastolic murmor is NOT a normal finding during pregnancy S3 gallop Complications dramatic shifts in cardiac physiology result in high pregnancy mortality in mothers with cyanotic heart disease can result in Eisenmenger syndrome Pulmonary Mucosal hyperemia nasal stuffiness increased nasal secretions Tidal volume ↑ → resting minute ventilation ↑ driven by progesterone stimulation of respiratory drive centers results in chronic respiratory alkalosis with renal compensation ↑ PO2 and ↓ CO2 arterial pH 7.40-7.45 increases 50% by term Functional residual capacity (FRC) ↓ by 20% residual volume (RV) ↓ expiratory reserve volume (ERV) ↓ Diaphragm is elevated by expanding uterus Vital capacity, inspiratory reserve, forced expiratory volume (FEV1), and maternal oxygenation do not change Dyspnea of pregnancy accompanies normal pregnancy in majority of women initiated first or second trimester Gastrointestinal Progesterone ↑ leads to ↓ GI tract motility ↓ lower esophageal tone → gastroesophageal reflux disease (GERD) constipation ↓ bile acid secretion → ↑ smooth muscle relaxation → slowed gallbladder emptying risk of cholelithiasis ↑ Cholesterol secretion ↑ due to estrogen ↑ risk of cholelithiasis ↑ Hemorrhoids due to constipation increased venous pressure uterus compressing inferior vena cava Renal Kidney size ↑ Progesterone ↑ leading to bladder tone ↓ dilation of ureters, renal pelvices, and calyces urinary stasis predisposes to urinary tract infection (UTI)/pyelonephritis Glomerular filtration rate (GFR) ↑ within 1 month of conception by second trimester increases 40-50% Glucosuria urine dipstick positive NOT useful in managing diabetes Proteinuria up to 150-200 mg/day in third trimester positive urine dipstick may occur ≥ 300 mg/day warrants further investigation Serum creatinine (Cr) and blood urea nitrogen (BUN) ↓ therefore serum Cr of 1.0 gm/dL suggests renal impairment in pregnant people small increases in Cr can indicate reduced renal function Hyponatremia of pregnancy not considered pathologic until below sodium concentration < 130 mEq/L Endocrine Pituitary gland size and vascularity ↑ susceptibility to Sheehan syndrome ↑ Fasting glucose ↓ Post-prandial glucose ↑ fetus produces own insulin at weeks 9-12 Thyroid binding globulin (TBG) ↑ due to ↑ estrogen leading to ↑ total T3 and T4 free T3 and T4 remain same (pregnant women are euthyroid) Cortisol and cortisol binding protein ↑ Skin Normal skin changes during pregnancy mimic liver disease due to ↑ estrogen can see spider angiomas can see palmar erythema Hyperpigmentation due to ↑ melanocyte stimulating hormone, estrogen, and progesterone umbilicus perineum face nipples areola genital areas linea nigra melasma Acne Vericose veins Striae