Tackling maternal obesity: The challenge for public health

Abstract

Dr Nicola Heslehurst from Teeside University and Dr Ruth Bell and Professor Judith Rankin from Newcastle University look at how pregnancy could be an opportune time to incite behavioural change to help prevent obesity development in women and children The increase in obesity in the UK population has significant implications for women of childbearing age and has recently been described as the biggest challenge for maternity services today.1 There are no pregnancy-specific BMI criteria to define maternal obesity. The BMI criteria for the general population2 are used to define obesity in early pregnancy as there is usually minimal weight gain in the first trimester. In addition to the World Health Organization (WHO) BMI categories of moderate (BMI 30-34.9 kg/m^sup 2^); severe (BMI 35-39.9 kg/m^sup 2^); and morbid (BMI ≥40 kg/m^sup 2^) obesity,2 there is an additional category used in the UK for pregnancy. A BMI ≥50 kg/m^sup 2^ in early pregnancy has been described as 'extreme obesity' or 'super morbid obesity'. This equates to approximately 92,500 pregnant women per year.3 The rest of the UK shows similar trends.1 A major public health concern is the association with health inequalities, as obese mothers are more likely to live in areas of high deprivation, be of black ethnic origin, unemployed and older than women with an ideal BMI.1,3 Most of these associations become stronger with increasing maternal BMI. For example, there is a twofold increase in moderately obese women living in areas of high deprivation compared with those residing in areas of low deprivation; this increases to an almost fivefold for extreme obesity.3 The increased risks associated with a raised BMI include stillbirth, maternal and infant mortality,4,5 and congenital anomalies that are a major contributor to childhood morbidity.6,7 Obese women are also more likely to require caesarean sections and to experience serious obstetric complications.8,9 Gestational diabetes is also more prevalent among obese women, which has long-term health implications due to an increased risk of developing type 2 diabetes for women and their children.10 Furthermore, it has been suggested that foetal exposure to maternal obesity during pregnancy may influence the development of obesity in the infant (via 'foetal programming'), although current evidence is inconclusive.11 Pregnancy also contributes towards the development of obesity through excessive gestational weight gain and postnatal weight retention. The antenatal period is an opportune time to engage women with behaviour change interventions as the health of the baby provides a powerful motivator. However, there is limited evidence on the effectiveness of interventions to change pregnant women's weight-related behaviours, as well as a lack of UK evidence-based guidelines for appropriate gestational weight gain. It is paramount that pregnant women are not encouraged to lose weight during pregnancy due to the potential related risks to the foetus, such as growth restriction and the development of congenital anomalies. Obese pregnant women should instead be advised to follow a healthy diet and be physically active.12 Further evidence from randomized controlled trials is needed to determine the safety and effectiveness of interventions to limit gestational weight gain. Discussing the implications of obesity with pregnant women is also a challenging area, with healthcare professionals feeling apprehensive about doing so. Midwives are very aware of the stigma associated with obesity and the sensitive and emotive nature makes it an uncomfortable discussion to initiate without jeopardizing their relationship with the expectant mother.13,14 The psychosocial relationship with weight for many women makes the message that 'obesity may increase pregnancy risks' a largely unwelcome one. How this issue is approached and managed by healthcare professionals is critical. Communication should be sensitively delivered to encourage continued engagement with antenatal services and to promote engagement with the appropriate public health services. …