Diet or exercise, or both, for weight reduction in women after childbirth

Background: Weight retention after pregnancy may contribute to obesity. It is known that diet and exercise are recommended components of any weight loss programme in the general population. However, strategies to achieve healthy body weight among postpartum women have not been adequately evaluated.

Objectives: The objectives of this review were to evaluate the effect of diet, exercise or both for weight reduction in women after childbirth, and to assess the impact of these interventions on maternal body composition, cardiorespiratory fitness, breastfeeding performance and other child and maternal outcomes.

Search strategy: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2006) and LILACS. We scanned secondary references and contacted experts in the field.

Selection criteria: All published and unpublished randomised controlled trials (RCT) and quasi-randomised trials of diet or exercise or both, among women during the postpartum period.

Data collection and analysis: Three review authors independently assessed trial quality and extracted data. Results are presented using relative risk for categorical data and weighted mean difference (WMD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity.

Main results: Six trials involving 245 women were included. Women who exercised did not lose significantly more weight than women in the usual care group (one trial; n = 33; WMD 0.00 kg; 95% confidence interval (CI) -8.63 to 8.63). Women who took part in a diet (one trial; n = 45; WMD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (four trials; n = 169; WMD -2.89 kg; 95% CI -4.83 to -0.95), lost significantly more weight than women in the usual care. There was no difference in the magnitude of weight loss between diet and diet plus exercise group (one trial; n = 43; WMD 0.30 kg; 95% CI -0.60 to 0.66). The interventions seemed not to affect breastfeeding performance adversely.

Authors' conclusions: Preliminary evidence from this review suggests that dieting and exercise together appear to be more effective than diet alone at helping women to lose weight after childbirth, because the former improves maternal cardiorespiratory fitness level and preserves fat-free mass, while diet alone reduces fat-free mass. For women who are breastfeeding, more evidence is required to confirm whether diet or exercise, or both, is not detrimental for either mother or baby. Due to insufficient available data, additional research, with larger sample size, is needed to confirm the results.