To avoid complications, women with obesity should lose weight before pregnancy

Women with obesity have increased risk in pregnancy compared with those in the healthy weight category, according to a new systematic review of research from academics at City University London, Trinity College Dublin and the University of Gothenburg.

The paper, which is published in the journal of Obesity Reviews, suggests women with overweight or obesity should lose weight before they become pregnant, and also highlights the current lack of support present for these women.

Maternal obesity – which is defined as having a BMI of 30 kg/m2 or over when starting pregnancy compared to the healthy weight category of between 18.5 and 24.9 kg/m2 - is linked with adverse outcomes for mothers and their babies. Problems can include gestational diabetes, high blood-pressure, pre-eclampsia, depression, instrumental and caesarean birth, and surgical site infection, all of which are more likely to occur in pregnant women with obesity compared to women with a healthy weight.

Maternal obesity is also linked to greater risk of pre-term birth, large-for-gestational-age babies, fetal defects, congenital anomalies, and perinatal death. Furthermore, breastfeeding initiation rates are lower and there is greater risk of early breastfeeding cessation in women with obesity compared with healthy weight women.

To get a comprehensive insight into all risks related to obesity in pregnant women, the researchers produced a systematic overview of 22 systematic reviews which looked at a total of 573 research studies which compared pregnant women of healthy weight with women with obesity, and measured a health outcome for mother and/or baby.

Dr Ellinor Olander, author on the study and Lecturer in Maternal and Child Health in the Centre for Maternal and Child Health Research at City University London, said:

"Our review has shown that women with a BMI of 30 or above – in other words, those with obesity, – have higher risks in pregnancy compared to those with a healthy weight. The potential complications can lead to longer duration of hospital stay and greater costs. As a result it is crucial to try and lose weight to reduce the chance of problems for the mother and child.

"However, it is important not to stigmatise women because of their weight. We need to support and encourage women with a high BMI to lose weight before they conceive. This support needs to be available to women planning their first pregnancy as well as new mothers who may have more children in the future. The benefits for them and their child can be significant."