gynecology and obstetrics
Hypertension in Pregnancy
Treatment of Hypertension in Pregnancy
For mild hypertension, conservative measures followed by antihypertensives if needed Methyldopa, beta-blockers, or calcium channel blockers tried first Avoidance of angiotensin-converting enzyme (ACE) inhibitors,angiotensin IIreceptor blockers (ARBs), and aldosterone antagonists For moderate or severe hypertension, antihypertensive therapy, close monitoring, and, if condition worsens, possibly termination of pregnancy or delivery, depending on gestational age Recommendations for chronic and gestational hypertension are similar and depend on severity. However, chronic hypertension may be more severe. In gestational hypertension, the increases in BP often occur only late in gestation and may not require treatment. Treatment of mild to moderate hypertension without renal insufficiency during pregnancy is controversial; the issues are whether treatment improves outcome and whether the risks of drug treatment outweigh risks of untreated disease. Because the uteroplacental circulation is maximally dilated and cannot autoregulate, decreasing maternal BP with medications may abruptly decrease uteroplacental blood flow. Diuretics reduce effective maternal circulating blood volume; consistent reduction increases risk of fetal growth restriction. However, hypertension with renal insufficiency is treated even if hypertension is mild or moderate. (systolic BP 140 to 159 mm Hg or diastolic BP 90 to 109 mm Hg) with labile BP, reduced physical activity may decrease BP and improve fetal growth, making perinatal risks similar to those for women without hypertension. However, if this conservative measure does not decrease BP, many experts recommend drug therapy. In pregnant women with mild chronic hypertension, a strategy of targeting a BP < 140/90 mm Hg was associated with decreased incidence of preeclampsia and preterm birth, without increase risk of small-for-gestational-age birth weight ( Treatment reference ). Women who were taking Forsevere hypertension(systolic BP ≥ 160 mm Hg or diastolic BP ≥ 110 mm Hg), drug therapy is indicated. Risk of complications—maternal (progression of end-organ dysfunction, preeclampsia) and fetal (prematurity, growth restriction, stillbirth)—is increased significantly. Several antihypertensives may be required. Forsystolic BP > 180 mm Hg or diastolic BP > 110 mm Hg,immediate evaluation is required. Multiple medications are often required. Also, hospitalization may be necessary for much of the latter part of pregnancy. If the woman’s condition worsens, pregnancy termination may be recommended. All women with chronic hypertension during pregnancy should be taught to self-monitor BP, and they should be evaluated for target organ damage. Evaluation, done at baseline and periodically thereafter, includes Serum creatinine, electrolytes, and uric acid levels Liver function tests Platelet count Urine protein assessment Usually funduscopy Maternal echocardiography should be considered if women have had hypertension for > 4 years. After initial ultrasonography to evaluate fetal anatomy, ultrasonography is done monthly starting at about 28 weeks to monitor fetal growth; Fetal Monitoring often begins at 32 weeks. Ultrasonography to monitor fetal growth and antenatal testing may start sooner if women have additional complications (eg, renal disorders) or if complications (eg, growth restriction) occur in the fetus. Delivery should occur by 37 to 39 weeks but may be induced earlier if preeclampsia or fetal growth restriction is detected or if fetal test results are nonreassuring. First-line medications for hypertension during pregnancy include Methyldopa Beta-blockers Calcium channel blockers Initialmethyldopadose is 250 mg orally twice a day, increased as needed to a total of 2 g a day unless excessive somnolence, depression, or symptomatic orthostatic hypotension occurs. The most commonly used beta-blocker islabetalol(a beta-blocker with some alpha-1 blocking effects), which can be used alone or withmethyldopawhen the maximum daily dose ofmethyldopahas been reached. Usual dose oflabetalolis 100 mg twice or 3 times a day, increased as needed to a total maximum daily dose of 2400 mg. Adverse effects of beta-blockers include increased risk of fetal growth restriction, decreased maternal energy levels, and maternal depression. Extended-releasenifedipine, a calcium channel blocker, may be preferred because it is given once a day (initial dose of 30 mg; maximum daily dose of 120 mg); adverse effects include headaches and pretibial edema. Thiazide diuretics are only used to treat chronic hypertension during pregnancy if the potential benefit outweighs the potential risk to the fetus. Dose may be adjusted to minimize adverse effects such as hypokalemia. Several classes of antihypertensives are usually avoided during pregnancy: ACE inhibitorsare contraindicated because risk of fetal urinary tract abnormalities is increased. ARBsare contraindicated because they increase risk of fetal renal dysfunction, lung hypoplasia, skeletal malformations, and death. Aldosterone antagonists(spironolactoneandeplerenone) should be avoided because they may cause feminization of a male fetus. 1.Tita AT, Szychowski JM, Boggess K, et al: Treatment for Mild Chronic Hypertension during Pregnancy.N Engl J Med386(19):1781-1792, 2022. doi:10.1056/NEJMoa2201295 