Researchers have quantified the amount of sleep loss experienced by first-time mothers in the weeks after giving birth and is the first to identify the unique type of sleep disruption that persists throughout the first months of motherhood, according to a new study at Sleep 2025.
Results show that the average daily sleep duration of new mothers was 4.4 hours during the first week after giving birth compared with a pre-pregnancy sleep duration of 7.8 hours. Their longest stretch of uninterrupted sleep also fell from 5.6 hours at pre-pregnancy to 2.2 hours in the first week after delivery. Nearly one-third of participants (31.7%) went more than 24 hours without sleep in the first week with a newborn.
RT’s Three Key Takeaways:
- Significant Sleep Loss After Birth – First-time mothers averaged just 4.4 hours of sleep per night in the first postpartum week, with nearly one-third going over 24 hours without sleep.
- Uninterrupted Sleep Remains Limited – Despite a gradual return to pre-pregnancy total sleep duration, mothers’ longest stretch of uninterrupted sleep remained far below baseline for up to 13 weeks.
- Sleep Fragmentation Impacts Health – Persistent sleep discontinuity, rather than sleep duration alone, may contribute to postpartum exhaustion and mental health risks, highlighting a need for targeted interventions.
The daily sleep duration of new moms increased to 6.7 hours across postpartum weeks 2 through 7 and 7.3 hours across weeks 8 through 13. However, their longest stretch of uninterrupted sleep remained significantly lower than pre-pregnancy levels at 3.2 hours in weeks 2 through 7 and 4.1 hours in weeks 8 through 13. This novel finding reveals that sleep discontinuity remains a problem for new mothers even as their total nightly sleep duration gradually returns to pre-pregnancy levels.
“The significant loss of uninterrupted sleep in the postpartum period was the most dramatic finding,” said lead author Teresa Lillis, who has a doctorate in clinical psychology and is an adjunct professor in the department of psychiatry and behavioral sciences at Rush University Medical Center in Chicago. “While mothers generally returned to their pre-pregnancy total nightly sleep duration after the first postpartum week, the structure of their sleep remained profoundly altered. 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.”
The study involved 41 first-time mothers between the ages of 26 and 43 years. They provided their wearable sleep data from their personal Fitbit devices for a full year before childbirth through the end of the first year after giving birth.
Lillis noted that these findings explain why new mothers continue to feel exhausted even when they get the recommended 7 or more hours of sleep per night. The study results also identify sleep discontinuity as a potential risk factor and intervention target for postpartum depression and other postpartum-related health issues.
“Our results validate the lived experience of new mothers’ exhaustion and provide a new target for sleep-related interventions,” she 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.”
