OS014. Which first-line drug to control severe hypertension in pregnancy? A pilot study

Severe hypertension is a common complication in pregnancy-associated hypertensive disorders and there is no clear consensus on which first-line antihypertensive drug to use in this setting.

To determine the efficacy and safety of four antihypertensive drugs (two intravenous and two oral) in pregnant women with severe hypertension.

Pilot prospective randomised study.

pregnant women with a gestational age >24weeks and admitted in the Obstetrics Department with severe hypertension defined as systolic blood pressure (SBP) ⩾165mmHg and/or diastolic blood pressure (DBP) ⩾105mmHg. The women were randomised in 4 groups to receive:-20mg intravenous labetalol;-5mg intravenous hydralazine;-10mg oral nifedipine tablets ;-10mg sublingual nifedipine. Treatment was repeated every 20mn until target SBP and DBP were reached (⩽150/⩽95mmHg). The primary endpoint was the time needed to achieve effective blood pressure control. Treatment failure was defined as the unability to reach the target BP within one hour.

After giving informed consent, 41 pregnant women admitted with severe hypertension were randomised. Mean age was 35 years (SD 3.5), 65% were nulliparous and mean SBP and DBP at admission were 176 (SD 16) and 105 (SD 12)mmHg, respectively. Success to achieve target BP was reached in all patients within the oral 10mg nifedipine group (11 patients), in all but one patients with the 10mg sublingual group (12 patients), and only in 5 out of 9 patients and 6 out of 9 patients within the labetalol and hydralazine groups. They were only one hypotension (defined as SBP <120mmHg) in the two groups with intravenous drugs and 3 and 5 in the oral and sublingual nifedipine groups.

These results indicate that oral nifedipine seems more effective than intravenous labetalol or hydralazine to reach BP control in pregnant patients with severe hypertension. A large scale randomized trial comparing oral nifedipine versus these commonly used intravenous antihypertensive drugs should be implemented in order to determine whether oral nifedipine is a more effective treatment in this population.