Sleep Characteristics During the First Year Postpartum in a Cohort of Black and White Women.

Study Objectives: The postpartum period is a unique time when sleep deficiency often occurs. Black and White adults are reported to have differences in sleep characteristics, but little is known if these differences exist in the postpartum period. Therefore, the purpose of this study was to examine sleep characteristics in a cohort of Black and White women from 6-8 weeks to 12 months postpartum.

Methods: Participants were 49 Black and 85 White women who gave birth to an infant at ≥37 weeks gestation. Participants were instructed to wear an Actiwatch for 7 days at 6-8 weeks, 4, 6, 9, and 12 months postpartum. Mixed-effects linear models with a race by time interaction were used to examine if characteristics differed between races over time.

Results: Only bedtime varied by race. White women had a later bedtime at 6-8 weeks compared to 6 months, but no significant change occurred for Black women. For the entire sample, average nighttime sleep duration increased from 385 minutes at 6-8 weeks to 404 minutes at 4 months postpartum. Percent sleep during the sleep interval and wake after sleep onset (WASO) improved by 6 and 9 months, respectively. However, average WASO remained >45 minutes and sleep efficiency <85% at all timepoints for both Black and White women. Compared to White women, Black women had significantly shorter sleep duration (range: 40.6-59.9 minutes shorter across all timepoints, p<0.0001) and time in bed (range: 17.5-67.6 minutes shorter, p=0.0046), and lower percent sleep (range: 0.7%-1.2% lower, p=0.0407) and sleep efficiency (range: 2.6%-5.7% lower, p=0.0005). Sociodemographic factors were associated with sleep outcomes in Black and White women while behavioral factors were associated with sleep outcomes in White women only.

Conclusion: While there were improvements in nighttime sleep duration and quality, sleep duration remained suboptimal, and quality remained poor throughout the first year postpartum. In this sample, differences existed in factors associated with sleep outcomes between Black and White women.