For otherwise healthy women, the increase in risk with obesity may not be as great as previously suspected.
'The increased risk was fairly modest for obese women who did not have conditions such as high blood pressure, diabetes or a previous caesarean section, and the risks were quite low if the woman had given birth previously,' said lead researcher Dr Jennifer Hollowell of the National Perinatal Epidemiology Unit at Oxford University.
'It is important to appreciate that we are not saying that obesity isn't important or that obesity doesn't increase a woman's risks during pregnancy,' she added. 'We found that around half of very obese women giving birth in obstetric units have medical problems or pregnancy complications when admitted. But our study focused on women who were obese but otherwise healthy when they went into labour, and some of them had much lower risks than might have been expected.'
Read more (Oxford University News)