Bigger families mean less shut-eye for mums... but dads sleep like babies
Every additional child increases a mother's chances of having her sleep disturbed by 50pc, research has shown.
However, the same does not apply to men: fathers continue to sleep like babies, no matter how many children they have, according to the US study.
"I think these findings may bolster those women who say they feel exhausted," lead researcher Dr Kelly Sullivan, from Georgia Southern University, said.
"Our study found not only are they not sleeping long enough, they also report feeling tired throughout the day."
The team analysed the results of a telephone survey of 5,805 people.
Participants were asked how long they slept each night, with seven to nine hours considered optimum and less than six hours insufficient.
Among 2,908 women aged 45 years and younger, a clear link was found between poor sleep and having children.
Each child in a household increased the chances of not getting enough sleep by 50pc.
Overall, 48pc of women under 45 with children reported getting at least seven hours of sleep compared with 62pc of those without children.
No other factors, including exercise, marital status and education, appeared to influence how long younger women slept.
Having children also affected how long younger women felt tired during the day.
Mothers reported feeling tired 14 days per month whereas women without children felt tired for 11 days.
Children had no effect on how long men slept, said the researchers whose findings were presented at the American Academy of Neurology's annual meeting in Boston.
"Getting enough sleep is a key component of overall health and can impact the heart, mind and weight," Dr Sullivan said.
"It's important to learn what is keeping people from getting the rest they need so we can help them work toward better health."