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33: Short and long sleep durations in pregnancy are associated with extremes of gestational weight gain

      Objective

      Epidemiologic data from non-pregnant cohorts have linked poor sleep with obesity and weight gain. Our objective was to determine the relationship between objectively measured sleep duration and weight gain in pregnancy.

      Study Design

      Women enrolled in the nuMoM2b study, a multi-center prospective cohort study of nulliparous women with a singleton gestation, were recruited at the 2nd study visit (16-21 weeks’) to wear an actigraph to record objective sleep activity for 7 consecutive days. Women with pregestational diabetes and chronic hypertension were excluded. Sleep duration (SD) was calculated as an average across study nights and categorized as follows: <6, 6 to <7, 7 to <8, 8 to <9, and >9 hours/night. Gestational weight gain (GWG) was calculated relative to self-reported prepregnancy weight using measured weights at visit 2 and visit 3 (22-29 weeks’), and chart abstracted last weight prior to delivery. We examined GWG using gestational age-standardized z-scores, a measure of GWG that by design is uncorrelated with gestational age at measurement and BMI. Z scores of <-1 and >+1 were used to define groups with the smallest and largest normalized weight gains, respectively.

      Results

      Actigraphy and weight data were available for 751 women. The majority of women (74.8%) had a SD between 7 to <9 hours; 2.1% and 5.2% had a SD of <6 and >9 hours/night, respectively. Non-linear relationships were observed between SD and GWG (see Table). For all GWG assessments, large GWG (Z>+1) became less frequent as SD increased. Women with the shortest (<6) and the longest (> 9) SD had the highest rates of small GWG (Z<-1). Differences were statistically significant for GWG at Visit 2 and Visit 3 (p<.0001, p=.04) and were similar in magnitude for the last weight prior to delivery (p=0.0504).

      Conclusion

      Our data suggests that both short and long SD in pregnancy are associated with GWG. Poor sleep in pregnancy has been linked to adverse pregnancy outcomes, and our findings provide one potential mechanism for this association.
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