Women who drive while pregnant are much more likely to crash, a new (and slightly whats-the-point study) has revealed.
Researchers have discovered for the first time that being pregnant increases the risk of women having a serious collision by 42 per cent.
But they stressed the risk of pregnant women hitting other vehicles was still lower than that of men of the same age.
Lead researcher Dr Donald Redelmeier, of the University of Toronto, said: "Pregnant women often worry about air flights, scuba diving, hot tubs and other topics in maternal health, yet individuals may overlook traffic crashes despite their greater health risks.
"These findings are not a reason to decide not to have children or a reason to stop driving; instead, the findings primarily emphasise the need to drive more carefully."
In a study of 500,000 pregnant women, they had an average of 177 crashes per month before getting pregnant. But this rose to 252 per month during pregnancy.
One in 50 pregnant women can expect to be involved in a serious car crash while at the wheel, according to the research published in the Canadian Medical Association Journal.
Dr Redelmeier warned: "Even a minor motor vehicle crash during pregnancy could lead to irreparable consequences for mother and child. These findings underscore the importance of prevention and indicate that good prenatal care includes safe driving."
No similar increase in accidents was seen among pregnant pedestrians or car passengers. Nor did pregnancy increase the rate of falls or risky behaviour.
The study looked at whether common features of pregnancy such as nausea, fatigue and insomnia might contribute to human error and increase the risk of traffic accidents.
The researchers highlighted the effects of 'baby brain' but stopped short of linking it directly to the raised risk of car accidents.
They wrote: "Subjective disturbances during pregnancy are commonly reported in the obstetrical literature where absentmindedness is denoted as 'baby brain' or other negative terms.
"Community surveys suggest that about half of pregnant women complain of sporadic cognitive lapses; however, laboratory studies in this setting provide results with uncertain clinical relevance."