Among 3,661 first-time mothers followed in the nuMoM2b Heart Health Study, mid-pregnancy sleep health — assessed across six domains including regularity, quality, sleepiness, timing, efficiency, and duration — was meaningfully associated with less weight retention 2–7 years postpartum. Each additional domain meeting healthy thresholds during mid-pregnancy (22–28 weeks gestation) reduced the risk of substantial weight retention (>11 lbs) by 4% (RR = 0.96). Healthy sleep duration and quality individually corresponded to 2–3 lbs less retained weight. Early-pregnancy findings were more mixed, with regular sleep timing counterintuitively linked to greater retention.
Postpartum weight retention is a well-established driver of long-term obesity risk in women, yet interventional targets remain limited. This analysis extends prior work linking poor prenatal sleep to excess gestational weight gain, now projecting those associations years beyond delivery — a clinically meaningful timeframe. The multidimensional sleep health framework used here is more comprehensive than most prior single-domain studies, strengthening its translational value. Limitations are notable: this is observational, sleep was self-reported rather than actigraphy-measured, and causality cannot be established. The unexpected regularity finding in early pregnancy warrants caution and replication. As a preprint posted on medRxiv and not yet peer-reviewed, these results should be interpreted with appropriate skepticism — the analyses and conclusions may change following expert scrutiny. Still, the consistency across mid-pregnancy domains positions sleep as a potentially modifiable prenatal target worth testing in randomized trials.
