Maternal habitual snoring and blood pressure trajectories in pregnancy

Study Objectives: Habitual snoring has been associated with hypertensive disorders of pregnancy. However, exactly when blood pressure (BP) trajectories diverge between pregnant women with and without habitual snoring is unknown. Moreover, the potentially differential impact of chronic vs pregnancy-onset habitual snoring on maternal BP trajectories during pregnancy has not been examined. This study compared patterns of BP across pregnancy in 3 groups of women: those with chronic habitual snoring, those with pregnancy-onset habitual snoring, and nonhabitual snoring "controls". Methods: In a cohort study of 1,305 pregnant women from a large medical center, participants were asked about habitual snoring 3 nights/week) and whether their symptoms began prior to or during pregnancy. Demographic, health, and BP data throughout pregnancy were abstracted from medical charts. Linear mixed models were used to examine associations between habitual snoring-onset and pregnancy BP trajectories. Results: A third of women reported snoring priorto pregnancy (chronicsnoring) and an additional 23% reported pregnancy-onset snoring. Mean maternal age (SD) was 29.5 (5.6), 30 (6), and 30.5 (5.7) years in controls, chronic, and pregnancy-onset snoring, respectively. Overall, women with pregnancy-onset snoring had higher mean systolic BP and diastolic BP compared to those with chronic habitual snoring or nonhabitual snoring. In gestational week-specific comparisons with controls, systolic BP became significantly higher around 18 weeks' gestation among women with pregnancy-onset snoring and in the third trimester among women with chronic snoring. These differences became detectable at 1 mm Hg and increased thereafter, reaching 3 mm Hg-BP difference at 40 weeks' gestation in women with pregnancy-onset snoring relative to controls. Pairwise mean differences in diastolic BP were significant only among women with pregnancy-onset snoring relative to controls, after 15 weeks' gestation. Conclusions: Pregnancy-onset and chronic maternal snoring are associated with higher BPs beginning in the second and third trimester, respectively. Pregnancy BP trajectories could identify critical windows for enhanced BP surveillance; the divergent BP trajectories suggest that the 2 groups of women with habitual snoring in pregnancy may need to be considered separately when gestational time intervals are evaluated for increased BP monitoring.