340: Intrapartum hypertension, diagnosis of preeclampsia and adverse neonatal outcomes

Abstract

The intrapartum diagnosis of hypertension is challenging given blood pressure (BP) measurements in labor may be affected by pain and hemodynamic changes. Our objective was to determine the prevalence of intrapartum hypertension and its clinical relevance. Secondary analysis of an intrapartum fetal heart rate monitoring trial that enrolled women with singleton gestation at >36 weeks gestation, who were attempting vaginal delivery, had ruptured membranes and a cervix 2-7 cm dilated. Women diagnosed with gestational hypertension (GHTN) or preeclampsia (PE) at the time of enrollment, or receiving magnesium sulfate, were excluded from the analysis, as well as those with chronic hypertension, lupus, or BP measured less frequently than every 30 minutes. BP was measured using an automated machine and digitally stored. The prevalence of various degrees of systolic and diastolic BP elevations after enrollment, and their associations with maternal outcomes and a composite neonatal outcome (intrapartum fetal death, neonatal death, Apgar score ≤ 3 at 5’, neonatal seizure, umbilical-artery blood pH ≤ 7.05 with a base deficit ≥ 12 mmol/L, intubation for ventilation at delivery, or neonatal encephalopathy) were determined. The prevalence of the various BP elevations is summarized in Table 1. One or more systolic BP >140 mmHg or diastolic BP >90 mmHg occurred in 64.5% of laboring women, and was not associated with the composite neonatal outcome or cesarean delivery (CD), but was associated with use of magnesium sulfate (MgSO4), and longer maternal length of stay. In addition to the association with the latter maternal outcomes, 2 or more BPs above these cutoffs at least 4 hours apart was also associated with higher CD rates. Multivariate logistic regression showed that when compared to normotensive women, increased BP with or without the diagnosis of GHTN or PE was associated with CD, but not adverse outcomes (Table 2). Two women had seizures after enrollment: one had normal BP but was diagnosed with GHTN /PE and the other had a single BP elevation BP elevations above the cutoffs used to diagnose hypertension are very common in labor and are not associated with adverse neonatal outcomes. They are, however, associated with higher cesarean rates and maternal length of stay, even if they do not lead to diagnosis of GHTN or PE