A Longitudinal Study Exploring Factors Influencing Weight Gain During Pregnancy and Subsequent Weight Loss and Retention up to One Year Postpartum

Obesity in women of reproductive age is a major factor facing primary and secondary healthcare provision, with half of women of childbearing age in the UK classified as overweight or obese (The Information Centre, 2008). The prevalence of obesity in pregnant women living in Nottingham City is estimated to be 18.4%, (Wilcox, 2011), compared to 15.5% in England as a whole (Heslehurst et al., 2010). Being overweight or obese during pregnancy increases the risk of morbidity and mortality attributed to a range of pregnancy-related complications (Galtier et al, 2008), with 49% of maternal deaths occurring in overweight or obese women (Cantwell et al., 2011). Women who are overweight or obese at conception are more likely to develop hypertensive or diabetic complications, to develop thrombosis, and to deliver macrosomic babies (Ramachenderan et al, 2008). Associated with this are increased rates of delivery complications, postpartum haemorrhage and caesarean section (Galtier et al., 2008), with obese women at greater risk of anaesthetic complications. There is also a greater risk of infections (Metwally et al, 2007). Risks posed to the baby include congenital abnormalities such as spina bifida and oral clefts (King, 2006), and an increased risk of childhood obesity and adult metabolic syndrome (Galtier et al, 2008). The societal and economic impact of obesity during pregnancy is therefore life-long.

Excessive weight gain during pregnancy has little positive effect on foetal growth and pregnancy duration (Scholl et al, 1995) and is associated with a similar range of adverse outcomes as described above (Guelinckx et al., 2008). It is also associated with a greater probability of post-partum weight retention. Linné et al (2004) showed that both normal weight and overweight/obese women who gained excessive weight were more likely to have retained more weight 1 and 15 years after pregnancy, compared to women who gained the recommended amount of weight during pregnancy.

Whilst the US Institute of Medicine recommends lower pregnancy weight gain ranges for overweight and obese women (IOM, 2009), there are currently no UK evidence based guidelines outlining an appropriate BMI-specific weight gain (NICE, 2009). The current UK guide for weight gain is 10 - 12.5kg for all women (DoH, 2009). There is concern expressed that women are not being informed of the risks associated with obesity during pregnancy, or of the importance of a safe weight gain during pregnancy (NICE, 2009).

A study on the views of health professionals highlighted the issue that dietary information is often ad-hoc, and that advice is not linked with weight management (Heslehurst et al, 2007). Wiles (1998) found that above average weight women felt they didn't receive relevant weight management information. NICE (2010) recommended that there was need for research to find effective and cost effective approaches to help women manage their weight before, during and after pregnancy, including those from disadvantaged, low income and minority ethnic groups. In order to develop better strategies for promoting healthy weight changes in this population, it is important to understand the knowledge, attitudes and beliefs, experience and expectations of pregnant women during and after pregnancy in relation to their body weight and the behavioural factors which influence body weight. However, there is a paucity of research in this field. A recent systematic review (Campbell, et al, 2008) identified just 8 studies, (in the UK since 1990, with the most recent being conducted in 2004), into the views and attitudes to diet, physical activity and weight gain in pregnancy.

Childbearing may affect attitudes towards body image and this psychological dimension of weight is also important in understanding postpartum weight retention. Relatively few studies have investigated the effects of risk factors on weight retention in postpartum women. Gaining this intelligence from representative population groups is necessary for the selection and development of effective strategies to aid the development and commissioning of services and pathways to help address maternal obesity and post partum weight management.