'More risks' for obese women on first pregnancies

Obese women giving birth for the first time are more likely to have premature and low birthweight babies, researchers said today.

They are also more likely to suffer pre-eclampsia – a condition linked to high blood pressure which can be fatal.

Research published in the American Journal of Obstetrics and Gynaecology found that obese women giving birth for the first time had particularly high risk.

Experts studied 385 obese women in their first pregnancy with a Body Mass Index (BMI) of more than 30.

The experts found that 18.8% of the babies born to these women were of lower than normal birthweight compared with around 10% in the average population.

A total of 13.4% of babies were higher than normal birthweight, compared with 10% in the average population.

A total of 11.7% of the women developed pre-eclampsia compared with 6% of obese women with one or more previous pregnancies and only 2% of the average population.

The rate of pre-eclampsia was almost double the figure in previous studies which included obese women on their first, second or subsequent pregnancies.

The study found that the risk of pre-eclampsia increased as BMI increased.

Meanwhile, the premature birth rate in the group was 11.9% – higher than the national average of 7% and higher than previously reported in obese women who had been pregnant before.

The Caesarean section rate of 39% in obese women was the highest ever reported in the world, the authors said.

In addition, women were more likely to need to stay in hospital the higher their BMI.

The study was funded by the baby charity Tommy’s, the Wellcome Trust and the Biomedical Research Centre at Guy’s & St Thomas’ NHS Foundation Trust.

Professor Lucilla Poston, who led the research, said: “There are a number of findings which are very surprising.

“The large proportion of small babies was particularly unexpected as obesity is more often associated with the birth of overweight babies.

“The high number of cases of pre-eclampsia found in this group was very concerning, as this is a serious pregnancy complication which, in extreme cases, can result in maternal and/or foetal death.

“We must now start to consider first-time pregnancy as an additional problem in obese pregnant women, who we know are already more likely than thinner women to have a complicated pregnancy.”

Mervi Jokinen, from the Royal College of Midwives, said: “Obesity is an issue that is becoming increasingly prominent in maternity care and midwives are aware of the complexities and potential problems that obesity brings into pregnancy.

“We need to ensure that women get early access to a midwife so that she can get lifestyle and weight management advice as soon as possible, and that this continues throughout the pregnancy and after the birth of the baby.

“This research also reinforces the need to tackle obesity not just as an issue for maternity services but as a much wider public health issue.

“This is a health problem that affects men as well as women and children as well as adults.”