What’s Really Hurting Moms’ Sleep Health and Leaving Them Exhausted

There’s no surprise that parenthood comes with its fair share of sleep deprivation. Especially those first weeks, parents often are running on fumes as they keep up with night feedings and restless newborns. But even as parents begin to claw back more sleep, even 7 or 8 hours can still leave you exhausted. So what’s up?

A new study presented at the SLEEP 2025 annual meeting found that for first-time moms, it’s not just the hours of sleep lost after giving birth that lead to overwhelming exhaustion; it’s the constant interruptions. Even months into postpartum, that broken sleep lingers, and it may be the real reason so many parents feel like they’re running on empty.

Researchers tracked 41 new moms using Fitbit data from a full year before birth through their baby’s first birthday. In the first week postpartum, moms averaged just 4.4 hours of total sleep each night, down from 7.8 hours pre-pregnancy. But what really stood out? Their longest stretch of uninterrupted sleep dropped from 5.6 hours to just 2.2 hours.

Sleep totals did gradually rebound—to 6.7 hours by week 7 and 7.3 by week 13—but that coveted long stretch of sleep remained fractured. At seven weeks postpartum, moms averaged just 3.2 hours of continuous sleep, increasing only slightly to 4.1 hours by 13 weeks.

Why is fragmented sleep such a problem? Unfortunately, eight hours broken into four chunks doesn’t come close to the benefits of a full night’s rest. Studies show that when sleep is interrupted, the body struggles to complete full sleep cycles—especially deep (slow-wave) and REM sleep, which are essential for physical recovery, memory consolidation and emotional regulation. Each wake-up essentially resets the cycle, making it harder for your brain and body to reach the truly restorative stages of sleep.

“The significant loss of uninterrupted sleep in the postpartum period was the most dramatic finding,” said lead author Teresa Lillis, PhD, a clinical psychologist and adjunct professor at Rush University Medical Center. “These results fundamentally transform our understanding of postpartum sleep; it’s not the lack of sleep, but rather, the lack of uninterrupted sleep that is the largest challenge for new mothers.”

Researchers point out that interrupted sleep doesn’t just have physical effects, but may be a key risk factor for postpartum depression. “Our results validate the lived experience of new mothers’ exhaustion and provide a new target for sleep-related interventions,” Lillis said. “Rather than simply encouraging mothers to ‘nap when the baby naps’, our findings show that mothers would most benefit from strategies that protect opportunities for uninterrupted sleep.”

Of course, getting that kind of quality rest is often easier said than done. But as more parents, partners and support systems begin to understand just how important uninterrupted sleep really is, there is hope that more attention and meaningful support can go toward creating space for protected sleep and true recovery for moms. Find tips for dealing with sleep deprivation and how to support a new parent.