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

Women naturally gain weight during pregnancy and many gradually lose it afterwards. Some women, though, find it difficult to lose the gained weight in the year or two following the birth of the baby and there is concern that this may be a health risk for them. The retention of weight gained during pregnancy may contribute to obesity, which can increase the risk of diabetes, heart disease and high blood pressure. It is suggested that women who return to their pre-pregnancy weight by about six months have a lower risk of being overweight 10 years later. The review looked for randomised studies to assess the impact of dieting or exercise, or both, on women's weight loss in the months after giving birth. It paid particular attention to breastfeeding women to be sure that breastfeeding was not compromised. The review of trials found 14 studies, with 12 studies involving 910 women carrying excess weight after childbirth that contributed data for analysis. The findings suggest that diet combined with exercise or diet alone compared with usual care seemed to help with weight loss after giving birth. There is potential for these interventions to play a role in preventing future maternal obesity. There was not sufficient evidence to be sure that exercise or diet did not interfere with breastfeeding though it appeared not to in the included studies. It seems preferable to lose weight through a combination of dieting and exercise, compared to dieting alone, because exercise is thought to improve circulation and heart fitness, and to preserve lean body mass. Further research is needed.

Authors' conclusions: 

Evidence from this review suggests that both diet and exercise together and diet alone help women to lose weight after childbirth. Nevertheless, it may be preferable to lose weight through a combination of diet and exercise as this improves maternal cardiorespiratory fitness and preserves fat-free mass, while diet alone reduces fat-free mass. This needs confirmation in large trials of high methodological quality. 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.

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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 (31 January 2012) and LILACS (31 January 2012). We scanned secondary references and contacted experts in the field. We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 30 April 2013 and added the results to the awaiting classification section of the review.

Selection criteria: 

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

Data collection and analysis: 

Both review authors independently assessed trial quality and extracted data. Results are presented using risk ratio (RR) for categorical data and mean difference (MD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity.

Main results: 

Fourteen trials were included, but only 12 trials involving 910 women contributed data to outcome analysis. Women who exercised did not lose significantly more weight than women in the usual care group (two trials; n = 53; MD -0.10 kg; 95% confidence interval (CI) -1.90 to 1.71). Women who took part in a diet (one trial; n = 45; MD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (seven trials; n = 573; MD -1.93 kg; 95% CI -2.96 to -0.89; random-effects, T² = 1.09, I² = 71%), lost significantly more weight than women in the usual care group. There was no difference in the magnitude of weight loss between diet alone and diet plus exercise group (one trial; n = 43; MD 0.30 kg; 95% CI -0.06 to 0.66). The interventions seemed not to affect breastfeeding performance adversely.

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