Risks of parenteral antihypertensive therapy for the treatment of severe maternal hypertension are low.

OBJECTIVE: To determine whether the incidence of hypotension or adverse fetal heart tracing (FHT) category change differed following antepartum administration of intravenous (IV) labetalol versus hydralazine.

METHODS: Blood pressure and FHT categories were assessed one hour before and after medication administration. Hypotension was defined as ≥30% reduction in baseline systolic blood pressure (SBP) or SBP <90 mmHg. Changes in mean arterial pressure (MAP) were also compared. The National Institute for Child Health and Human Development (NICHD) three-tier category system was used to describe the FHT. For all category II tracings, Parer and Ikeda's system was also used.

RESULTS: Sixty-nine women received hydralazine and 31 women received labetalol during the study period. The incidence of hypotension (≥30% reduction in SBP) was similar between the labetalol (10%) and hydralazine (11%) groups (p = 0.98). No women experienced post-treatment SBP <90 mmHg. No association was observed between fetal heart rate category change and drug used. No women required emergent delivery for fetal indications.

CONCLUSIONS: The incidence of maternal hypotension was low and did not differ following antepartum IV labetalol versus hydralazine use. These data should reassure providers about the use of parenteral labetalol and hydralazine for the treatment of severe hypertension.