MedicalResearch.com Interview with: Theresa A Lawrie World Health Organization Department of Reproductive Health and Research Geneva, Switzerland MedicalResearch: What is the background for this study? Response: Excessive weight gain in pregnancy is associated with various undesirable outcomes in pregnancy. The aim of the review was to assess data from all relevant clinical trials in the field, to determine whether diet and/or exercise interventions during pregnancy were effective in reducing the chance of excessive weight gain in pregnancy. We also wanted to know whether these interventions could reduce the chance of having large babies (macrosomia), as this is associated with difficult labor, c/section, postpartum hemorrhage, birth injuries and other complications. MedicalResearch: What are the main findings? Response: Altogether 49 trials contributed data to the review. Approximately half the trials recruited women of any pre-pregnancy weight, the other half recruited women who were overweight or obese at the start of pregnancy. Most of the trials were conducted in high income countries. Interventions varied, some involved individual counseling, others group sessions, some were counseling interventions only, other programs were actively supervised by fitness trainers. Health outcomes for women receiving the intervention programs in addition to routine antenatal care (the intervention group) were compared with those of women receiving the routine antenatal care only (the control group). We found that diet or exercise or combined interventions led to an average 20% reduction in the number of women gaining excessive weight in pregnancy. This reduction was fairly consistent across the different types of interventions, although the largest effect was observed for combined diet and supervised exercise interventions. Overall findings suggested a small reduction in caesarean section (of about 5%) and in large babies (of about 7%).  However, a bigger reduction in large babies (in the region of a 19% reduction) was noted for exercise-only interventions, which were more likely to be supervised interventions. Other findings: We also found no difference in the risk of preterm birth between groups. Fewer women in the intervention group were assessed as having high blood pressure during pregnancy (although we assessed this as low quality evidence). Low quality evidence also suggested that women in the intervention group were likely to retain less weight at six months postpartum compared with the control group. Interestingly, data from two studies suggested that women receiving diet and exercise interventions were less likely to have babies with breathing difficulties at birth. These findings will hopefully be corroborated by other studies. A limitation of the review, is that we did not include gestational diabetes as an outcome as this is partly covered in a separate Cochrane review. Our exploratory analyses, however, suggested that there may be a reduction in gestational diabetes for certain types of interventions, and we hope to include these data in future review updates. In general, we did not find differences in outcomes for women according to pre-pregnancy weight or BMI.