Postpartum weight retention (PPWR) is a strong predictor of obesity in later life with long term health consequences in women. Suboptimal lifestyle behaviours (e.g. diet and physical activity) contribute to PPWR. Postpartum lifestyle interventions are known to be efficacious in reducing PPWR, however there are challenges to their successful implementation.
The prevalence of overweight and obesity is on the rise globally, presenting a challenge to public health . In 2016, 44% (>2 billion) of adults worldwide had overweight or obesity . In particular, women of reproductive age are at an increased risk of having overweight or obesity . Global data reports that among women, the prevalence of having overweight and obesity was 39% and 15% respectively in 2016, compared to around 23% and 6%, respectively, in 1975 . Weight gain associated with childbirth contributes to obesity risks in women , with excessive gestational weight gain (weight gain above the Institute of Medicine (IOM) recommendations during pregnancy) and postpartum weight retention (PPWR) (retention of the weight gained during pregnancy) being significant contributors to parity-related weight gain . Excessive gestational weight gain is also a major predictor of PPWR both in the short and long term . On average PPWR ranges from 0.5 to 3 kg; however, this is highly variable, with up to 20% of women retaining >4 kg at 1 year postpartum . PPWR is therefore a strong predictor of obesity in later life and also predisposes women to an increased risk of chronic diseases such as cardiovascular disease, diabetes, osteoarthritis and some cancers .
Most maternal health guidelines around the world do not address postpartum weight or lifestyle . There is need for clear implementation strategies to guide evidence translation into practice to deliver public health impact.
Lifestyle behaviours, sociodemographic and psychosocial factors may contribute to PPWR . There is generally a decline in healthy dietary behaviours from pregnancy through to postpartum . Diet quality was reported to be higher in the first postpartum year compared to subsequent years indicating that the decline in diet quality continues even after the first postpartum year . Lee et al.’s review reported less adherence to healthier dietary patterns, specifically decreased fruit and vegetable intake and increased intake of energy-dense and nutrient-poor food during the transition from pregnancy to postpartum . This worsening of lifestyle behaviours in the postpartum period could be due to the demands associated with caring for a child .
Irregular sleep and meal times during the postpartum period could also interfere with body weight. A recent study reported that greater caloric intake at night was independently associated with PPWR . A positive association between short sleep duration and PPWR has also been reported in a previous review .
Physical activity levels are generally inadequate in postpartum women . The decline commences in late pregnancy and although there is a progressive improvement 3 to 12 months postpartum, it still remains lower than pre-pregnancy levels . The decline in physical activity is observed in leisure-time physical activity  and moderate to vigorous physical activity but not in walking . Postpartum physical activity is beneficial for the improvement of aerobic fitness, insulin sensitivity and psychological wellbeing . Physical activity may also be beneficial for postpartum weight loss ; however, the evidence on its effect is limited . In postpartum women, the maintenance of light physical activity such as walking, with a decline in moderate to vigorous physical activity may be insufficient by itself for weight control . Therefore, physical activity may need to be combined with dietary interventions to obtain maximum benefits in weight management, as per the general population .
Psychosocial factors such as depression and anxiety are also predictors of PPWR. Previous systematic reviews reported the prevalence of depression and anxiety in the postpartum period as 17% and 15%, respectively . A positive association between postpartum depression and PPWR or maternal obesity  but no association between anxiety  or stress and PPWR  were reported in previous reviews.
There is inconsistency in the literature on the effect of breastfeeding on postpartum weight with systematic reviews reporting beneficial , negative  or inconclusive  effects of breastfeeding on PPWR. Jiang et al. reported a beneficial effect of breastfeeding for 6–12 months which was more pronounced in women younger than 30 years old, primipara or having normal pre-pregnancy BMI , while He et al. reported a negative effect of breastfeeding ≤6 months and no effect of breastfeeding >6 months . Neville et al.’s systematic review concluded that there was insufficient evidence to suggest that breastfeeding was directly associated with postpartum weight change  with 63% of the observational studies included in the review reporting no significant differences in postpartum weight change between breastfeeding and non-breastfeeding mothers . The energy cost of breastfeeding is up to 500 kcal per day, and therefore, lactation may help mobilize fat stores built up during pregnancy leading to weight loss provided there is no compensatory increase in energy intake . The provision of breastfeeding support is a potentially effective strategy that has not been explored in postpartum lifestyle interventions for weight management .
Diet and physical activity behaviours are modifiable lifestyle behaviours that can be targeted for postpartum weight loss. Postpartum interventions including a combination of diet and physical activity components are efficacious for postpartum weight loss and improvement of body composition with mean difference (MD) in body weight of -2.33 kg (95% confidence interval (CI), -3.10 to -1.56) reported and sustained at 12 months postpartum.
Implementation is critical to the effective translation of existing evidence on the efficacy of postpartum lifestyle interventions into practice and to allow delivery of sustainable health impact on a large scale. Lim et al. reported that postpartum weight management interventions had greater efficacy when delivered by health professionals and when combining diet and physical activity components. The ideal setting and delivery format of postpartum lifestyle interventions should seek to address the barriers of childcare, time constraints and social support in order to maximize engagement while tailoring to the contextual needs of the target population. The total number of BCTs and including the BCTs ‘goal setting’ and ‘self-monitoring of behaviour’ was associated with a greater reduction in energy intake and greater efficacy of physical activity interventions. Although the efficacy of lifestyle interventions in postpartum women has been established, their impact at the population level is determined by the program reach (penetration) and engagement (participation). Lifestyle interventions targeting postpartum women rarely address penetration, implementation and participation, focusing instead only on the intervention effects. This leads to a lack of data to inform intervention strategies that are associated with better penetration or participation. This may contribute to the lack of translation from efficacy studies to real-world solutions in postpartum lifestyle management. It is important that interventions for postpartum women address the specific barriers to lifestyle management in this group. These barriers could hinder participation in lifestyle interventions and contribute to high attrition rates of up to 42% as reported in previous systematic reviews. The influence of the family on postpartum women’s willingness to engage in lifestyle modification has previously been reported. The support and involvement of partners in postpartum lifestyle interventions is particularly crucial for lasting behaviour change especially in high-risk women who have experienced gestational diabetes or preeclampsia. Cultural values and norms can also impact on postpartum lifestyle choices.
Support from health professionals play a key role in facilitating behaviour change in postpartum women. Health professionals are valued as a credible source of information for the new mother, therefore health professionals should use this opportunity to not only provide support in terms of breastfeeding and care of the newborn but also for lifestyle behaviour counselling and support. Comprehensive clinical guidelines for routine postpartum care are limited and do not include recommendations for lifestyle or behavioural counselling. Guidelines for weight management in the postpartum period are similarly limited with a general lack of guidance on how to implement the evidence into clinical practice. There is a need for health care policies to incorporate lifestyle counselling into routine care for postpartum women. This could be through the integration of postpartum care with child immunization clinics.
The core components associated with efficacy of postpartum lifestyle interventions are: inclusion of both diet and physical activity components, delivery by healthcare professionals, use of electronic health technology, including more BCTs (especially self-monitoring and goal setting) and embedding interventions in existing services. It is also important to train health professionals in time management and counselling skills to equip them to adequately support postpartum women. Including these components in the design while tailoring interventions to postpartum women’s specific needs and addressing barriers may be effective strategies to improve penetration and participation and reduce attrition rate. One strategy to do this is to co-design lifestyle interventions and include postpartum women and their partner in the planning, development and implementation processes. This is necessary to improve implementation by improving program feasibility for adoption and acceptability among women leading to increased program effectiveness. Considering the high prevalence of postpartum weight retention and the lack of translation of research evidence to practice on this topic, this review is an imperative for action to address implementation challenges through pragmatic, real-world trials for the effective translation of evidence into clinical practice to reduce postpartum weight retention.