Pregnant women with a normal BMI receiving dietary, lifestyle and exercise advice compared with routine antenatal care to improve maternal and infant health outcomes.

There are well-recognised associations between excessive gestational weight gain (GWG) and adverse pregnancy outcomes, including an increased risk of high blood pressure in pregnancy, gestational diabetes, and caesarean birth. The aim of the OPTIMISE randomised trial was to evaluate the effect of dietary and exercise advice among pregnant women who were considered to be in the healthy weight range, on pregnancy and birth outcomes. The trial was conducted in Adelaide, South Australia. Pregnant women with a body mass index in the healthy weight range (18.5 – 24.9 kg/m2) were enrolled in a randomised controlled trial of a dietary and lifestyle intervention versus standard antenatal care. The dietitian-led dietary and lifestyle intervention over the course of pregnancy, and was based on the Australian Guide to Healthy Eating. When we looked at the results we found that the two study groups, dietary and lifestyle intervention group and standard care group, were of similar age, starting weight, ethnicity and number of previous pregnancies. We found that women in the intervention group improved their diet, and pregnancy and birth outcomes were similar between the two groups including infant birthweight above 4 kg, a risk factor for childhood obesity. Women in both groups gained a similar amount of weight during pregnancy.