From the Guidelines
Induction of labor is recommended for well-controlled pregnancy-induced hypertension (PIH) at 37 weeks of gestation. This recommendation is based on the most recent and highest quality evidence, which suggests that induction of labor at 37 weeks is associated with improved maternal outcomes 1. The rationale for delivery at 37 weeks is that PIH is a progressive condition that can rapidly deteriorate, potentially leading to severe complications such as eclampsia, HELLP syndrome, placental abruption, or fetal compromise.
Key Considerations
- Earlier delivery at 34-36 weeks may be considered if blood pressure becomes difficult to control, laboratory abnormalities develop, or signs of maternal or fetal compromise emerge 1.
- Prior to induction, patients should receive appropriate antihypertensive medications if needed, such as labetalol, nifedipine, or methyldopa 1.
- Those with preeclampsia should receive seizure prophylaxis with magnesium sulfate during labor and for 24 hours postpartum 1.
- The decision to induce labor should be individualized and based on the specific clinical circumstances, including the severity of the hypertension, the presence of any complications, and the gestational age of the fetus.
Management of Hypertension
- Antihypertensive drugs should be reduced or ceased if diastolic BP falls < 80 mm Hg 1.
- Acceptable agents for urgent treatment of severe hypertension include oral nifedipine or intravenous labetalol or hydralazine 1.
- Women with preeclampsia should be assessed in hospital when first diagnosed, and thereafter, some may be managed as outpatients once it is established that their condition is stable and they can be relied on to report problems and monitor their BP 1.
From the Research
Gestation for Labor Induction in Well-Controlled PIH
- The optimal timing of birth for women with chronic or gestational hypertension at term was investigated in the WILL Trial 2.
- The trial found that planned birth at 38+0-3 weeks resulted in birth an average of 6 days earlier, with no differences in poor maternal outcome or neonatal morbidity.
- A Cochrane review of planned early delivery versus expectant management for hypertensive disorders from 34 weeks gestation to term found that planned early delivery was associated with lower risk of composite maternal mortality and severe morbidity 3.
- The review suggested that planned early delivery may be beneficial for women with hypertensive disorders after 34 weeks, but further studies are needed to determine the optimal timing of delivery for different types of hypertensive diseases.
- Other studies have also investigated the management of pregnancies complicated by hypertensive disorders, including the use of antihypertensive therapy and the role of aspirin prophylaxis 4, 5, 6.
Key Findings
- Planned birth at 38+0-3 weeks may be a safe option for women with well-controlled PIH 2.
- Planned early delivery is associated with lower risk of composite maternal mortality and severe morbidity 3.
- Further studies are needed to determine the optimal timing of delivery for different types of hypertensive diseases and to investigate infant and maternal morbidity and mortality outcomes.
Recommendations
- The European guidelines recommend initiating drug treatment in pregnant women with persistent elevation of blood pressure ≥ 150/95 mmHg and at values > 140/90 mmHg in women with gestational hypertension 4.
- The Japan Society of Hypertension and the Japan Society for the Study of Hypertension in Pregnancy recommend that the basic treatment for PIH is the interruption of pregnancy, and antihypertensive therapy should be given for protection in mother complicated by severe hypertension 6.