Two perinatal sleep studies, one gap: nobody is asking the question

Poor sleep after a baby is treated as a fact of life rather than a clinical finding, which is a reasonable default and an expensive one. Two studies published in the Journal of Clinical Sleep Medicine on 31 August approach the same blind spot from different directions: one measures how much diagnosable insomnia is going unrecognised after delivery, the other measures what a different, treatable sleep disorder during pregnancy predicts [s1][s2].

What is being missed after delivery

The first study prospectively recruited adults who delivered a live infant at two academic US hospitals, with a pre-specified cross-sectional analysis at six weeks postpartum [s1]. Participants completed the Bergen Insomnia Scale, the PROMIS sleep disturbance and sleep-related impairment surveys, and a structured clinical interview for sleep disorders — the SCISD-R, the diagnostic standard — until 150 interviews were finished [s1].

Of 188 patients who accepted an interview invitation, 150 completed one (79.8%), at a mean of 44 days postpartum (SD 7), with a mean age of 33 years (SD 5) [s1].

Insomnia symptoms were reported by 38 participants (25.3%), and 20 (13%) met diagnostic criteria for insomnia disorder [s1]. Two had received clinical evaluation [s1].

That single sentence is the finding. Thirteen per cent of a sample met a diagnostic threshold for a condition with established treatments, and roughly one in ten of them had been assessed for it.

The survey scores complicate the picture in a useful way. Among 144 respondents, median scores were 20 on the Bergen Insomnia Scale (IQR 14–27), 51 on PROMIS sleep disturbance (IQR 45–56) and 57 on sleep-related impairment (IQR 50–62) — indicating normal sleep disturbance and mild sleep-related impairment in most participants [s1]. Yet 51% reported low or very low sleep satisfaction and 70% reported sleeping six hours or less [s1].

In other words, the standard instruments read close to normal in a population where half the respondents were dissatisfied with their sleep. The authors describe this as revealing a gap in current sleep medicine frameworks that may leave affected patients overlooked [s1]. Diagnostic accuracy for identifying insomnia disorder was moderate: areas under the curve of 0.73 for the Bergen scale, 0.85 for PROMIS sleep disturbance and 0.70 for sleep-related impairment [s1].

No statistically significant risk factors for insomnia disorder emerged, which the authors attribute to insufficient power rather than a true null [s1].

What restless legs predicts during pregnancy

The second study followed 2,435 Japanese pregnant women in the control group of a randomised trial on perinatal depression [s2]. Restless legs syndrome status was assessed in the second and third trimesters using the short form of the Cambridge-Hopkins diagnostic questionnaire and modelled as a time-varying exposure — a design choice that matters, because restless legs typically worsens across pregnancy and a single baseline measurement would misclassify it [s2].

Incident major depressive episodes and depressive symptoms from the second trimester to three months postpartum were assessed with the WHO Composite International Diagnostic Interview 3.0 and the Edinburgh Postnatal Depression Scale [s2].

Restless legs prevalence was 1.6% in the second trimester (40 participants) and 3.5% in the third (60) [s2]. Over a mean follow-up of 6.5 months (SD 3.2), 69 participants developed perinatal depression [s2].

Time-varying restless legs status was associated with an increased risk of incident perinatal depression: hazard ratio 3.04 (95% CI, 1.22–7.58), and 2.12 (95% CI, 1.28–3.51) for depressive symptoms defined as an EPDS score of 13 or above [s2]. The associations remained after adjustment for potential confounders [s2].

Reading them together, and reading them carefully

Both papers point toward the same operational conclusion — screen for sleep disorders in pregnancy and after delivery — and both are weaker than that conclusion on their own.

The postpartum study is a single cross-sectional snapshot at 150 interviews across two academic hospitals [s1]. Its prevalence estimate is not necessarily generalisable, and its central observation about undiagnosis reflects the referral practices of two institutions.

The restless legs study has a precision problem that its hazard ratio makes obvious. The confidence interval for incident perinatal depression runs from 1.22 to 7.58 [s2] — the finding is compatible with a small effect and with an enormous one, because it rests on 69 depression events and a maximum of 60 exposed participants at any timepoint. The association with depressive symptoms is estimated more tightly [s2] but is a symptom-scale outcome rather than a diagnosis.

Neither study shows that treating the sleep disorder changes the mental-health outcome. The restless legs authors say so explicitly: whether treating it can reduce perinatal depression risk requires further investigation [s2].

What the two together do establish is that a common, measurable and often treatable class of condition is going largely unassessed at exactly the point in life when sleep disruption is treated as unremarkable — and that at least one of these conditions carries a signal worth taking seriously.

Sources

• [s1] "Insomnia disorder at 6 weeks postpartum: a prospective study," Journal of Clinical Sleep Medicine, 31 August 2026. https://doi.org/10.1007/s44470-026-00150-3
• [s2] "Time-varying restless legs syndrome and risk of incident perinatal depression," Journal of Clinical Sleep Medicine, 31 August 2026. https://doi.org/10.1007/s44470-026-00168-7