The physiological changes of pregnancy, specifically venous stasis, edema, and hypercoagulability caused by activated Table 4. Summary of Antihypertensive Drugs Used During Pregnancy Category Maternal Side Effects Teratogenicity or Fetal-Neonatal Adverse Effects Class/Level of Evidence (see Table 2) Centrally acting 2-adrenergic agonist (eg, methyldopa) Sedation, elevated LFTs, depression No IIa/C Diuretics (thiazide) Hypokalemia No III/B -Blockers (atenolol) Headache Associated with fetal growth restriction III/B -Blockers (pindolol, metoprolol) Headache Possible fetal growth restriction, neonatal bradycardia IIa/B Calcium channel blockers (eg, nifedipine) Headache; possible interaction with magnesium sulfate; may interfere with labor No I/A Combined - blockers (labetalol) May provoke asthma exacerbation Possible neonatal bradycardia IIa/B Hydralazine Reflex tachycardia, delayed hypotension Neonatal thrombocytopenia, fetal bradycardia III/B ACE inhibitors, angiotensin receptor blockers, renin inhibitors Skeletal and cardiovascular abnormalities, renal dysgenesis, pulmonary hypoplasia III/C ACE indicates angiotensin-converting enzyme; and LFTs, liver function tests. Modified from Umans et al120a with permission from Elsevier, Copyright 2009. *American College of Obstetricians and Gynecologists Bulletin withdrawn in lieu of a newer version. Access date was May 15, 2013. Bushnell et al Guidelines for Prevention of Stroke in Women 1553 protein C resistance, lower levels of protein S, and increased fibrinogen, combine to make pregnancy and the postpartum period a time of increased risk for stroke. Pregnancy-related hypertension is the leading cause of both hemorrhagic stroke and IS in pregnant and postpartum women.145 147 Hypertensive Disorders of Pregnancy Preeclampsia/eclampsia and pregnancy-induced hypertension are the 2 most important hypertensive disorders of pregnancy. Preeclampsia is defined as progressively worsening high BP in pregnancy that occurs in the setting of proteinuria ( 300 mg of protein in a 24- hour urine specimen).148 Preeclampsia may be of early onset (before 37 weeks gestation) or late onset (after 37 weeks). Eclampsia is preeclampsia that progresses to seizures. 