As any new parent will attest, looking after a baby can leave you feeling exhausted.
But mothers suffer far more than fathers from interrupted sleep after having children, research suggests.
For every child a woman has, the chances of regularly not getting enough sleep goes up by 50 percent, scientists have found.
But men’s sleep patterns are unaffected by fatherhood, no matter how many children they have, the researchers claimed. They said this showed that women were disproportionately affected by parenthood.
Study leader Dr Kelly Sullivan, from Georgia Southern University in the US, said: "I think these findings may bolster those women who say they feel exhausted.
"Our study found not only are they not sleeping long enough, they also report feeling tired throughout the day."
The team interviewed 5 805 people aged 45 and under about their sleeping habits, with seven to nine hours considered optimal and less than six hours insufficient. Among 2 908 women a clear link was found between poor sleep and having children.
Overall, 48 percent of women with children reported getting at least seven hours of sleep compared with 62 percent of those without children.
And each child in a household increased the chances of not getting enough sleep by a further 50 percent. But for the 2 897 men in the study, no difference was found between those who had children and those who did not.
No other factors, including exercise, marital status and education, appeared to influence how long younger women slept.
Dr Sullivan said: "Children in the household were associated with the frequency of feeling unrested among younger women, but not among younger men. This fits with other research that has shown that women report sleep difficulties about twice as often as men and actually need more sleep than men in order to feel rested.
"There are also biologic considerations unique to women that have to be considered throughout the life cycle such as hormonal influences of pregnancy and menopause, as well as the demands of breastfeeding."
The findings will be presented at the American Academy of Neurology’s annual meeting in Boston in April.
The study found that not only was living with children associated with how long younger women slept, but also how often they felt tired.
Younger women with children reported feeling tired 14 days per month, on average, compared to 11 days for younger women without children in the household.
Dr Sullivan added: "Getting enough sleep is a key component of overall health and can impact the heart, mind and weight.
"It’s important to learn what is keeping people from getting the rest they need so we can help them work towards better health.
"Prioritising healthy sleep is important and includes limiting caffeine intake, keeping the bedroom dark and reducing exposure to bright screens such as phones and TVs close to bedtime."