Most parents who come to you for help have been running on less than seven hours of sleep for months. You already know this from experience. But a 2024 study published in Behavioral Sleep Medicine, titled “New Parents’ Sleep, Movement, Health, and Well-Being Across the Postpartum Period” by Kracht, Blanchard, Symons Downs, Beauchamp and Rhodes, now gives us hard numbers and a timeline. And one finding stands out above the rest: the connection between sleep and stress works on completely different schedules for mothers and fathers. This is something that can change the way you plan your support for each parent.
Who was studied and how
The researchers followed 181 first-time parents in Canada, 93 mothers and 88 fathers, from 2 months to 8 months postpartum. All were over 18, in married or common-law relationships, and the sample was predominantly White (83.3%) and well-educated. At 2 months, 94.5% of the mothers were breastfeeding and 92.8% were on maternity leave. By 8 months, 84.6% were still breastfeeding and 76.3% were still on leave. Fathers returned to work much earlier, only about 9 to 10% remained on paternity leave from 4 months onward.
Each parent completed questionnaires at 2, 4, 6 and 8 months postpartum. The researchers measured five things: sleep duration (using the Pittsburgh Sleep Quality Index), physical activity, perceived stress, physical quality of life and life satisfaction. They used a statistical method called random-intercept cross-lagged panel models. This allowed them to see whether a change in one area, say, sleep, predicted a later change in another say, stress and whether these patterns looked different for mothers compared to fathers.
59% of parents were sleeping under seven hours at two months
At 2 months postpartum, only 40% of all parents in the study met the recommended 7 to 9 hours of sleep per night. The average was just 6.4 hours. By 4 months, about 55% had reached the guideline. But that number barely moved after that- at 8 months, it was 53.6%.
This means that roughly half of new parents are still not sleeping enough when their baby is 8 months old.
For sleep consultants, the number itself is useful. But think about what it means for the parent sitting in front of you. A person who has slept under seven hours for months will struggle to process information, to make decisions and to stay emotionally steady. The pace of your conversations, the amount of detail you give at once, and the way you check for understanding – all of that should reflect the fact that most of your clients are cognitively and emotionally running at a lower level than they normally would.
Fathers get a bit more sleep but not as much as you might expect
Fathers reported sleeping more than mothers at 4 months (by about 20 minutes per night) and at 6 months (by about 27 minutes per night). At 2 and 8 months, the difference was not significant.
These are small gaps. Cohen’s d was 0.19 to 0.27 – small effect sizes by any standard. Both parents were sleeping below guidelines throughout the study. The gap most likely reflects the fact that most mothers were breastfeeding and were the primary nighttime caregivers.
What this does not mean is that fathers are fine. Both parents are short on sleep. Both need support. If your consultations focus only on the breastfeeding mother, the father’s needs go unaddressed – even though his sleep loss is almost as severe.
Stress did not drop over the first eight months
Here is a finding that surprised me. You might assume that as a baby gets older, the parents feel less stressed. The data says otherwise. Perceived stress scores stayed between 13 and 14 (out of 40) across all four time points. There was no significant change from 2 months to 8 months, and no significant difference between mothers and fathers at any point.
The sources of stress probably shifted. At 2 months, parents may worry about feeding and sleep patterns. At 8 months, they may deal with teething, separation anxiety or the pressure of returning to work. But the overall level of stress remained the same.
This is directly relevant to how we work with families. A parent who calls you at 7 months is just as likely to be overwhelmed as a parent at 2 months. Do not assume that more experienced parents need less emotional support.
The sleep-stress cycle hits fathers early and mothers late
This is where the research gets genuinely interesting and genuinely useful for daily practice.
The researchers found that sleep and stress are connected for both parents. That is not news. What is new is the timing.
For fathers, sleep and stress were already intertwined at 2 months postpartum. Fathers who slept less reported more stress, and fathers with more stress slept less. The cycle was active from the start.
For mothers, that same pattern did not appear until 8 months. At that point, shorter sleep was associated with higher stress, and higher stress with shorter sleep. The researchers also found that mothers’ stress at 6 months predicted more sleep at 8 months. They interpret this as a possible recovery response, the body pushing for more rest after a prolonged period of elevated stress.
So what can you do with this? If you are working with a family at 2 or 3 months, ask the father how he is sleeping. He may not bring it up on his own. He may not even recognise that his rising stress is linked to his broken sleep. A simple question could open the door to real support.
If you are working with a family at 6 or 7 months, pay close attention to the mother. She may be approaching the point where sleep deprivation and stress start feeding into each other. This often coincides with the end of maternity leave or a shift in household routine. Your guidance at this moment is not just about baby sleep, it is about the mother’s own health.
Feeling better comes before being active
The study found something that goes against a common assumption. We often hear that new parents should exercise more, and that exercise will lift their mood. This study tested whether physical activity predicted better health or whether health predicted later activity. The data pointed in one direction: parents who reported higher life satisfaction at 2 months became more physically active at 4 months. Well-being came first. Movement followed.
The authors concluded that supporting health and well-being may be the path to improved physical activity in new parents, not the other way around.
For sleep consultants, the connection to your work is direct. When you help a parent sleep better, you are not only addressing the immediate complaint. Better sleep can reduce stress and improve mood. And if well-being is what sets physical activity in motion, then what you do for a family’s sleep may be the first step in a much wider recovery.
Where the study has limits
This was a Canadian sample, predominantly White, well-educated and with access to generous parental leave. The results may not apply to families in countries with no paid leave, to single-parent households, or to parents from different cultural and economic backgrounds.
Sleep was measured by self-report, one question about average nightly hours. The study did not track night wakings, sleep efficiency or sleep quality. It collected no data about the infants: not their sleep patterns, temperament or developmental stage. These are all factors that directly shape how parents sleep.
The study stopped at 8 months. Many families face sleep difficulties well beyond that age.
Kracht, C. L., Blanchard, C. M., Symons Downs, D., Beauchamp, M. R., & Rhodes, R. E. (2024). New parents’ sleep, movement, health, and well-being across the postpartum period. Behavioral Sleep Medicine, 22(5), 636–649. https://doi.org/10.1080/15402002.2024.2339815