Evaluation of gestational weight management interventions for women with obesity

Background: The prevalence of extreme obesity (body mass index (BMI) ≥40kg/m²) is increasingly common during pregnancy. Women with obesity and their infants are at increased risk of adverse outcomes including excessive gestational weight gain (GWG) and increased risk of childhood obesity. Aim: The primary aim of this thesis was to explore GWG management among women with a BMI ≥40kg/m². Methods: An overview of systematic reviews on the effectiveness of lifestyle interventions to reduce GWG in women with overweight or obesity was undertaken followed by a sequential explanatory mixed methods study. This included: 1. A dominant quantitative component collecting retrospective data to explore the impact of an antenatal healthy lifestyle service for women with a BMI≥40kg/m² on GWG, pregnancy and birth outcomes and childhood obesity up to age 5. 2. A supplementary qualitative component undertaking semi-structured interviews with thirteen women with a BMI≥40kg/m² to explore their experiences of gestational weight management. Key findings: Findings across the research programme were integrated narratively. The findings indicated a lack of impact of most antenatal healthy lifestyle services. Within the overview of systematic reviews current lifestyle interventions among women with overweight or obesity reduced average GWG by 0.3 to 2.4kg but had minimal impact on clinical outcomes. Similarly, the antenatal healthy lifestyle service made no difference to mean GWG. There were no beneficial clinical effects from the antenatal healthy lifestyle service (3 visits) except for a higher rate of breastfeeding at discharge compared to women in the comparison cohort. Nor was there any association between lifestyle service attendance and childhood overweight or obesity up to 5 years. Socio-demographic context and parity were noted to be important. Those from more deprived backgrounds were less likely to attend the service and more likely to have a child with overweight or obesity by school age. The antenatal healthy lifestyle service appeared to be effective among multiparous women, as those offered three visits had a lower rate of weight gain and fewer small for gestational age infants. Within the qualitative interviews women highlighted the stigma they experienced, especially when healthcare providers placed excessive focus on the risks of obesity during pregnancy without providing practical advice and support. The final integrated finding suggested the need to refine interventions in terms of their content, timing and format. Conclusion: Lifestyle based interventions may cause a small reduction in GWG, however their impact on clinical outcomes was minimal. More holistic approaches to weight management during pregnancy are required for women with obesity, with future interventions focussing on environmental and social factors, not just changing individual behaviour. Original contribution: This work makes an original contribution by evaluating experiences and outcomes of antenatal weight management in women with a BMI≥40kg/m², a subgroup frequently lacking in previous research. Additionally, it explored the long-term association between antenatal weight management service attendance and childhood obesity, which has seldomly been undertaken previously.