Objective
To assess the frequency of obstructive sleep apnea among women with and without hypertensive disorders of pregnancy.
Design
Cohort study.
Setting
Obstetric clinics at an academic medical center.
Population
Pregnant women with hypertensive disorders (chronic hypertension, gestational hypertension, or pre-eclampsia) and normotensive women.
Methods
Women completed a questionnaire about habitual snoring and underwent overnight ambulatory polysomnography.
Main Outcome Measures
The presence and severity of obstructive sleep apnea.
Results
Obstructive sleep apnoea was found among 21 of 51 women with hypertensive disorders (41%), but in only three of 16 women who were normotensive (19%, chi-square test, P = 0.005). Non-snoring hypertensive women typically had mild obstructive sleep apnea but >25% of snoring hypertensive women had moderate-to-severe obstructive sleep apnea. Among the hypertensive women, the mean apnea/hypopnea index was substantially higher in snorers than non-snorers (19.9±34.1 vs. 3.4±3.1, p=0.013) and the oxyhemoglobin saturation nadir was significantly lower (86.4±6.6 vs. 90.2±3.5, p=0.021). Among hypertensive women, after stratification by obesity the pooled relative risk for obstructive sleep apnea in snoring women with hypertension compared to non-snoring hypertension was 2.0 [95%CI 1.4–2.8].
Conclusions
Pregnant women with hypertension are at high risk for unrecognised obstructive sleep apnea. While longitudinal and intervention studies are urgently needed, it would seem pertinent given the known relationship between obstructive sleep apnea and hypertension in the general population, that hypertensive pregnant women who snore should be tested for obstructive sleep apnea, a condition believed to cause or promote hypertension.