Eur J Obstet Gynecol Reprod Biol. 2026 May 18;324:115196. doi: 10.1016/j.ejogrb.2026.115196. Online ahead of print.

ABSTRACT

BACKGROUND: Sleep disturbances are common during pregnancy and tend to worsen as gestation progresses. Although poor maternal sleep has been suggested to adversely affect fetal and newborn health, existing evidence remains limited and inconsistent.

OBJECTIVES: To examine associations between maternal sleep disturbances during pregnancy and newborn birthweight and standardized birthweight (primary outcomes) and selected indicators of neonatal health at birth (secondary outcomes).

METHODS: A total of 2,750 mothers were included in this prospective cohort study. Validated sleep questionnaires concerning sleep duration, sleep quality, insomnia symptoms, sleepiness and snoring were administered three times during pregnancy and at delivery. Associations between maternal sleep disturbances and neonatal outcomes (birthweight, standardized birthweight, 1-minute Apgar score, umbilical artery pH, and NICU admission) were evaluated using cross-sectional and exploratory longitudinal (post hoc) models, adjusted for a comprehensive set of clinically relevant covariates and corrected for multiple comparisons using FDR.

RESULTS: The cohort comprised predominantly low-risk pregnant women with approximately equal proportions of nulliparous and multiparous women. Sleep quality deteriorated across gestation, with slightly shorter sleep duration, increased nocturnal awakenings, and higher insomnia scores, while changes in daytime sleepiness and perceived sleep loss were modest; neonatal outcomes were largely within normal ranges. In covariate-adjusted and FDR-corrected cross-sectional analyses, in late pregnancy, frequent nocturnal awakenings (>3 per night) were associated with higher birthweight (β = 54.1 g, 95% CI 15.9-92.3; FDR-adjusted p = 0.012), with a similar association observed at delivery (β = 71.0 g, 95% CI 28.6-113.4; FDR-adjusted p = 0.0049. For standardized birthweight, frequent nocturnal awakenings were associated with a higher z-score (β = 0.15, 95% CI 0.05-0.25; FDR-adjusted p = 0.012) at delivery. A modest association between early pregnancy nocturnal awakenings and higher umbilical artery pH was observed (β = 0.015; 95% CI 0.005-0.026; FDR-adjusted p = 0.016), within the normal physiological range. No other associations were observed in cross-sectional or longitudinal models after adjusting for confounding factors and correction for multiple testing.

CONCLUSIONS: Maternal sleep quality worsened across gestation, particularly toward late pregnancy. Fragmented sleep in late pregnancy was associated with modest increases in birthweight. Nevertheless, the observed effect sizes were small, and the overall findings suggest that maternal sleep disturbances and insomnia symptoms during pregnancy are unlikely to substantially compromise fetal growth.

PMID:42218893 | DOI:10.1016/j.ejogrb.2026.115196