Snoring, not insomnia, linked to pregnancy hypertension

Hypertensive disorders of pregnancy, including gestational hypertension and preeclampsia, are among the most serious maternal complications, and clinicians are keen to identify risk factors that can actually be spotted and acted on. Sleep problems in pregnancy are extremely common and have increasingly been proposed as one such factor, but individual cohort studies have disagreed on whether they matter and which ones do. Lumping all sleep complaints together also risks confusing disturbed sleep with disordered breathing, which are biologically quite different problems. This review set out to pool the cohort evidence and separate the two.

The authors ran a systematic review and meta-analysis of cohort studies, searching PubMed, Embase, Web of Science and Scopus from database inception through 3 April 2026. Eligible studies followed pregnant women and reported the association between sleep disorders during pregnancy and gestational hypertension, preeclampsia or hypertensive disorders of pregnancy as a combined outcome. Nineteen cohort studies from multiple countries met the criteria, together involving 9,460,018 pregnant women. Pooled odds ratios with 95% confidence intervals were calculated using fixed- or random-effects models depending on heterogeneity, and subgroup analyses were run by type of sleep disorder, including timing of sleep-disordered breathing within pregnancy.

Overall, sleep disorders during pregnancy were significantly associated with increased risk of gestational hypertension (OR 1.50, 95% CI 1.23-1.82), preeclampsia (OR 1.83, 95% CI 1.53-2.18) and hypertensive disorders of pregnancy combined (OR 1.56, 95% CI 1.17-2.08). The subgroup analyses were where the detail lay: obstructive sleep apnoea showed the strongest and most consistent associations, with gestational hypertension (OR 1.60) and preeclampsia (OR 2.13). Snoring was associated with elevated risks of preeclampsia and hypertensive disorders. Increased apnoea-hypopnoea index in mid-pregnancy was linked to higher risk of both outcomes, whereas an increased index in early pregnancy was not. Insomnia and poor sleep quality measured by the Pittsburgh Sleep Quality Index showed no significant association.

The pooled result confirms the broad suspicion that maternal sleep health tracks with hypertensive risk, but it also sharpens it considerably. The signal appears to sit with breathing during sleep rather than with the subjective experience of sleeping badly, which is the sort of distinction that gets lost when studies report a single catch-all sleep variable. Because every included study was observational, confounding remains a live concern, particularly with factors that raise both apnoea risk and blood pressure. The timing finding, with mid-pregnancy but not early-pregnancy apnoea-hypopnoea index predicting risk, raises an unanswered question about whether the breathing problem is a cause or an early consequence of the same physiology. No trial evidence here shows that treating sleep-disordered breathing changes outcomes.

This is a reason to treat snoring and suspected sleep apnoea in pregnancy as a signal worth mentioning to a clinician, rather than as a nuisance to be tolerated. It is equally a reason not to panic about ordinary broken sleep or a poor score on a sleep-quality questionnaire, neither of which was significantly associated with hypertensive outcomes in this pooled analysis. The findings describe risk across millions of pregnancies, not the fate of any individual, and an association of this kind cannot tell you that fixing the breathing would fix the risk. The practical value is in awareness of which sleep symptoms carry the evidence behind them.