Background: In Australia, 1 in 3 women of reproductive age are obese, but no pre-pregnancy weight loss interventions have been shown to reduce the risk of obesity-related pregnancy complications for both mother and child. The HAPO study (NEJM 2008;358:1991-2002) observed that small changes in maternal glucose at 26-28 weeks gestation are associated with significant changes in the rate of adverse pregnancy outcomes.
Aim: To determine if substantial pre-conception weight loss (10-15% body weight) in obese (BMI>30kg/m2) women reduces fasting glucose at 26-28 weeks gestation by ≥10% compared with modest (≤3%) weight loss.
Method: 78 women were randomised to either a lifestyle program expecting modest weight loss (MWL; ≤3% body weight; n=38), or a modified VLED program expecting substantial weight loss (SWL; 10-15% body weight; n=40). Attrition over the 12-week program was 20% (MWL 10/38 (25%), SWL 6/40 (15%)). Only completers were considered in the preliminary analysis. Subjects were followed for 12 months and if pregnancy occurred, maternal plasma glucose was measured at 26-28 weeks gestation. Of the 24 subjects who were >6 months post-intervention, 10 were pregnant and had completed 28 weeks gestation.
Results: Weight loss in the MWL (n=28) and SWL (n=34) groups was 2.1% and 13.1% respectively. Mean reduction in plasma glucose after 12 weeks was 1.24% (SE 1.40) in MWL and 9.12% (SE 1.83) in SWL group. Of those who achieved pregnancy (MWL= 3, SWL=7), mean decrease in plasma glucose between the start of the weight loss program and 26-28 week gestation was 1.85% (SE 1.83) and 11.51% (SE 3.17) in the MWL and SWL groups respectively.
Conclusion: This pilot data suggests that, in obese women, pre-conception weight loss results in a decrease in fasting plasma glucose which is maintained into pregnancy. The reduction in plasma glucose is greater when substantial pre-pregnancy weight loss is achieved.