The treatment of hypertension during pregnancy: when should blood pressure medications be started?

Abstract

Hypertensive pregnancy disorders (HPD) are important causes of maternal and fetal morbidity and mortality worldwide. In addition, a history of HPD has been associated with an increased risk for maternal cardiovascular disease later in life, possibly because of irreversible vascular and metabolic changes that persist beyond the affected pregnancies. Therefore, treatment of HPD may not only improve immediate pregnancy outcomes, but also maternal long-term cardiovascular health. Unlike the recommendations for hypertension treatment in the general population, treatment recommendations for HPD have not changed substantially for more than 2 decades. This is particularly true for mild to moderate hypertension in pregnancy, defined as a blood pressure of 140-159/90-109 mm Hg. This review focuses on the goals of therapy, treatment strategies, and new developments in the field of HPD that should be taken into account when considering blood pressure targets and pharmacologic options for treatment of hypertension in pregnant women.

Figure 1

Renovascular hypertension during pregnancy. A 36 year old woman presented at 14 weeks in her first pregnancy for management of hypertension. She was started on Labetalol 100 mg twice a day. Her follow up blood pressure (BP) was 184/114 mm Hg and evaluation for secondary causes of hypertension was initiated. A Doppler study of the renal arteries showed markedly elevated velocities in the mid-distal right renal artery, peak systolic velocity (PSV) of 533cm/sec, consistent with fibromuscular dysplasia (FMD) causing a high-grade right renal artery stenosis, and borderline elevated velocities in the left renal artery (PSV 199cm/sec), suggesting probable moderate stenosis caused by FMD of the left renal artery. The decision was made to optimize her medical management, with intervention to be considered only if she were to fail pharmacotherapy. The dose of labetalol was gradually increased to 200 mg four times a day and, ultimately, nifedipine XL 90 mg was added. On that regimen, her systolic BP averaged 122–144 mm Hg, diastolic 78–92 mm Hg for the remainder of her pregnancy. At 38 weeks of gestation (BP of 146/94 mm Hg), she delivered, by Caesarean section, a healthy 2.8 kg baby boy with Apgar score of 8 and 9 at 1 and 5 minutes, respectively. Six-months postpartum, she underwent a renal angiogram with successful bilateral angioplasty (Figure 1A and 1B, right renal artery, before and after angioplasty, respectively.). She is currently normotensive and off all BP medications.

Figure 1

Renovascular hypertension during pregnancy. A 36 year old woman presented at 14 weeks in her first pregnancy for management of hypertension. She was started on Labetalol 100 mg twice a day. Her follow up blood pressure (BP) was 184/114 mm Hg and evaluation for secondary causes of hypertension was initiated. A Doppler study of the renal arteries showed markedly elevated velocities in the mid-distal right renal artery, peak systolic velocity (PSV) of 533cm/sec, consistent with fibromuscular dysplasia (FMD) causing a high-grade right renal artery stenosis, and borderline elevated velocities in the left renal artery (PSV 199cm/sec), suggesting probable moderate stenosis caused by FMD of the left renal artery. The decision was made to optimize her medical management, with intervention to be considered only if she were to fail pharmacotherapy. The dose of labetalol was gradually increased to 200 mg four times a day and, ultimately, nifedipine XL 90 mg was added. On that regimen, her systolic BP averaged 122–144 mm Hg, diastolic 78–92 mm Hg for the remainder of her pregnancy. At 38 weeks of gestation (BP of 146/94 mm Hg), she delivered, by Caesarean section, a healthy 2.8 kg baby boy with Apgar score of 8 and 9 at 1 and 5 minutes, respectively. Six-months postpartum, she underwent a renal angiogram with successful bilateral angioplasty (Figure 1A and 1B, right renal artery, before and after angioplasty, respectively.). She is currently normotensive and off all BP medications.