The risk of complications in pregnant women who are severely obese

Our researchers have been finding out about the risks facing pregnant women with severe obesity and investigating whether the likelihood of complications is higher in a second pregnancy than in a first.
  • Author's list

    Professor Rebecca Reynolds, Professor Fiona Denison, Dr Emma Johns, Dr Elizabeth Wastnedge

    Start date: April 2019
    End date: April 2020

  • Research centre

  • Research status

    Completed projects

Why do we need this research?

Women with a BMI of 40 or higher are classed as severely obese. These women are more likely to develop complications during pregnancy, and in some cases, this can lead to poorer outcomes for both mother and baby. We thought that the risk of complications may be different in a first pregnancy than in a second and wanted to find out more.

What happened in this project?

Tommy’s researchers looked at data from over 200 severely obese women who were cared for by NHS Lothian to find out how many of them experienced complications during their pregnancy. During a first pregnancy, 14% of women developed gestational diabetes, 11% had pregnancy-induced high blood pressure and 45% suffered a haemorrhage after birth. 1 in 5 babies had a very high birth weight (97th centile or higher). During a second pregnancy, some complications were seen more often – 22% of women had gestational diabetes and 2 in 5 babies were born on the 97th centile or higher. 1 in 5 women gained more than 10kg in weight between their first and second pregnancies, although weight gain between pregnancies did not appear to have an impact on the chances of a woman experiencing complications.

These results show that pregnancy complications are common in severely obese women, and that the risk is even higher in a second pregnancy.

What difference will this project make?

The number of pregnant women with severe obesity is increasing. The results of this project will give healthcare providers a greater understanding of the risks facing these women and their babies, which will help them to provide the best possible care during and after pregnancy. In particular, it may be helpful to test these women for gestational diabetes early in their pregnancies, and to give them support with postnatal weight loss before any further pregnancies.