Women with severe preeclampsia (severe high blood pressure) during pregnancy may be treated with extended-release nifedipine, a blood pressure-lowering medicine, daily during the labor and delivery process, according to new research published in Hypertension, an American Heart Association journal. Women treated with the medicine were less likely to experience dangerously high blood pressure that would require treatment with fast-acting medicines including intravenous (IV) medications.
The study examined whether treatment with nifedipine, an extended-release blood pressure-lowering medication, leading up to labor and delivery may prevent severe blood pressure levels from developing, and, as a result, avoid the need to administer fast-acting IV medications.
According to the American Heart Association, preeclampsia is typically diagnosed after 20 weeks of pregnancy and indicates high blood pressure measures with symptoms such as headaches, vision changes and swelling of the hands, feet, face or eyes. A diagnosis of preeclampsia with severe features typically includes systolic blood pressure (the top number in a blood pressure measurement) of 160 mm Hg or higher and/or diastolic blood pressure (the lower number in a blood pressure measurement) of 110 mm Hg or higher, and high protein levels in the urine. It affects up to 8% of pregnancies and increases the risk of stroke, liver or kidney damage and pre-term delivery (delivery before 40 weeks). Delivery of the baby is the only way to start to cure preeclampsia, and symptoms usually go away within days of delivery. However, some women continue to need blood pressure medication for six weeks after delivery or longer.
Severe high blood pressure also raises the risk for complications such as placental abruption, where the placenta, which supplies the baby developing in the uterus with nutrients and oxygen from the mother, detaches from the uterus before the baby is born. This may lead to serious complications for mother and/or the baby.
The study was conducted from June 2020 to April 2022 at The Ohio State University Wexner Medical Center in Columbus and included 110 women who were at least 22 weeks pregnant, diagnosed with severe preeclampsia and who underwent induction of labor. Half of the participants were randomly assigned to take one 30 mg pill of nifedipine extended-release each day until delivery, the other half of participants were randomly assigned to take a placebo pill daily until delivery. Neither the study investigators, clinical care team, nor the women knew if they were assigned to take nifedipine or the placebo. Participants were followed through hospital discharge, and chart review was performed through 6 weeks postpartum to monitor for any postpartum readmissions along with reasons for readmission.
The researchers also examined the impact of nifedipine treatment on delivery, if and how long the baby may have needed care in the neonatal intensive care unit (NICU) and other adverse outcomes for the mother and/or baby.
The study found:
- 34% of women in the nifedipine group needed acute hypertension therapy (immediate reduction in blood pressure) compared to 55.1% of those in the placebo group.
- There were fewer Cesarean deliveries among the women treated with nifedipine: 20.8% of women in the nifedipine treatment group had a Cesarean section, compared to 34.7% of women in the placebo group.
- The rate of NICU admission for the newborns was lower if the mother was treated with nifedipine (29.1%) compared to the placebo group (47.1%).
- Poor outcomes for the infant –such as lower Apgar score, low blood sugar levels, high bilirubin or needing extra oxygen – did not differ significantly between the two treatment groups.
