Seventy percent of pregnant women expect poor sleep after their babies arrive—and a groundbreaking study from the University of Pennsylvania suggests those worried expectations may actually help create the very sleep problems they fear. The research, led by clinical health psychologist Sammy Dhaliwal at the Perelman School of Medicine, reveals that what expectant mothers believe about postpartum sleep becomes a surprisingly powerful predictor of their actual sleep quality after delivery, sometimes outweighing factors like previous sleep disorders, psychiatric history, or how many children they've had before.
The finding matters because postpartum sleep disruption affects an estimated 60 to 80 percent of new mothers and carries real consequences—increased risk of depression, anxiety, and impaired well-being during a vulnerable time. Yet many women and healthcare providers treat sleepless nights as simply an unavoidable part of early parenthood, a rite of passage rather than something worth preventing.
Dhaliwal's team followed 432 pregnant women beginning at approximately 24 weeks of gestation, asking them about their attitudes and beliefs regarding postpartum sleep, measuring their current sleep quality, and screening for depression and anxiety. The researchers repeated these assessments at 6, 12, and 24 weeks after birth. A smaller group of 49 women also wore wrist actigraphy devices—objective sleep-tracking technology—to measure actual sleep patterns in the weeks following delivery.
The results were striking. Among first-time mothers without prior health concerns, those who anticipated greater sleep disruption during pregnancy experienced significantly more fragmented sleep postpartum, as confirmed by both the objective actigraphy data and the women's own reports of how they were sleeping. Even more telling: among women who predicted the worst sleep quality, higher postpartum anxiety significantly worsened both measured and perceived sleep problems—independent of how anxious they had been during pregnancy itself.
"Most pregnant women in our sample anticipated poor postpartum sleep before it occurred, and it was striking that those expectations predicted worse sleep outcomes even after accounting for factors such as prior sleep disorders, psychiatric history and number of previous births," Dhaliwal said. "This suggests that attitudes and beliefs about sleep during pregnancy may represent a modifiable target for early intervention before postpartum sleep problems emerge."
The implications point toward a more hopeful path forward. Instead of waiting for new mothers to struggle with sleep, healthcare providers might intervene during pregnancy by addressing the beliefs and anxieties surrounding postpartum rest. Treating prenatal sleep-related worry and postpartum anxiety as part of routine care could help prevent the very problems so many women expect to face.
Dhaliwal notes that this approach requires shifting how we talk about postpartum sleep—moving beyond resignation about sleepless nights toward recognition that our expectations shape our reality. The research abstract was published in the journal Sleep and will be presented at the SLEEP 2026 annual meeting in Baltimore in June, opening doors for future studies on whether targeted psychological interventions during pregnancy can break this cycle and help new mothers get the rest they desperately need.