should aim to limit the overall amount of weight they put on, according to the findings of new research.
The largest population-based study into weight gain during pregnancy
carried out by Saint Louis University School of Medicine, confirmed widespread suggestions that obese women should not gain weight during pregnancy, it said.
Published in the October issue of Obstetrics & Gynecology, it examined the pregnancies of more than 120,000 obese women from Missouri to see how weight gain affected preeclampsia, Caesarean delivery and birth size.
Women with a body-mass index (BMI) of 35 and who gain fewer than the recommended 15 pounds are less likely to develop preeclampsia, less likely to need a Caesarean delivery and more likely to have a baby of normal weight, the research concluded.
The university's Dr Artal said: "It’s been shown in the literature time and time again.
"Weight gain increases in subsequent pregnancies because women accumulate weight with each pregnancy and don't lose it."
Recently the BBC reported that obese pregnant women were a "burden" to the NHS, because they needed more care than mother-to-be of a more normal weight.