(Medical Xpress)—How women perceive their bodies during pregnancy and how that impacts on their weight gain has been the subject of a new study by University of Adelaide researchers.

Researchers in the University's Robinson Institute and the School of Psychology have studied more than 400 South Australian women to better understand the links between body image and excessive weight gain during pregnancy.

The results, published in the journal Women and Birth, show that more than 70% of pregnant women who are overweight or obese under-estimate their weight. Those who under-estimate their weight are more likely to experience a higher rate of weight gain during pregnancy.

The research was conducted by PhD student Zhixian Sui in the University's Robinson Institute, under the supervision of Professor Deborah Turnbull (School of Psychology) and Professor Jodie Dodd (Robinson Institute and Women's and Children's Hospital).

"There is very little research around the world that describes women's perception of body size and shape in early pregnancy. Because obesity and excessive weight gain pose a range of health risks for mother and child during pregnancy, and are linked to health problems in later life, it's important for us to better understand this issue," Professor Turnbull says.

Just 26% of women surveyed correctly identified their body mass index (BMI,) with 70% under-estimating and 4% over-estimating their BMI.

"Women who incorrectly identified their BMI were significantly more likely to have higher gestational weight gain, which suggests a disconnect between their perceptions and the realities of their weight," Professor Turnbull says.

Professor Dodd says: "The findings of our study have significant implications for clinicians delivering weight-related messages to women during pregnancy, and highlight the very complex influence of maternal perceptions and diet-related behaviors.

"Previous research has shown that women make healthy changes if they believe their health is at risk and if they have awareness of potential negative outcomes. We suggest that health care providers promoting healthy weight gain during pregnancy should integrate strategies to increase the awareness of potential risks in overweight and obese women."

More information: www.sciencedirect.com/science/article/pii/S1871519213000735