Around half of new mothers are still excessively tired four months after giving birth, a new study has found.

Australian researchers assessed the sleep patterns and tiredness levels of new mothers and found that even though most were getting a stable night's sleep by the time their child was 18 weeks old, they were still excessively sleepy.

According to the researchers, sleep disruption can strongly influence how we function during the daytime, ‘with sleepiness recognised as a risk factor for people performing critical and dangerous tasks'.

"With the birth of every baby the new mother must adjust to the demands of parenting and one aspect of that is to remain functional while experiencing potentially severe sleep disruption," commented Dr Ashleigh Filtness of the Queensland University of Technology.

She pointed out that if any other person presented to a GP with the degree of sleepiness found in new mothers, ‘they would likely be offered advice regarding implications for daytime impairment including the impact on sustaining attention and decision making'.

The study noted that while most of the mothers who took part were getting adequate sleep time, the problem was this sleep time tended to be disturbed.

"What we found was that inevitably, new mothers will wake in the night to attend to their infant and the number of times they wake remains consistent during the first 18 postpartum weeks," Dr Filtness said.

However, it is not all bad news. Sleep disruption after 18 weeks appeared to reduce and this was ‘driven by a reduction in the time it took for new mums to return to sleep, suggesting improved efficiency by mothers at settling their infant or the development of the infant's circadian rhythm'.

"These findings highlight the importance of sleep quality as opposed to sleep quantity, especially during the first 12 weeks. Soon-to-be mums should be aware of the importance of their own sleep and consider how they are going to preserve their own sleep during the first few months of caring for a baby," Dr Filtness added.

The study involved 33 healthy new mothers and details of the findings are published in the journal, PLoS ONE.

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