Obesity is a growing problem in east London with a fifth of women entering pregnancy as obese. In addition to obesity, other metabolic risk factors such as raised lipids, high blood pressure and insulin resistance are increasingly prevalent. With a large proportion of ethnic minority mothers in east London, dietary habits and underlying genetic predisposition are major contributors to this phenomenon. Obesity and raised serum lipids, especially triglycerides increase the risk of complications such as preeclampsia in pregnancy and cardiovascular events such as myocardial infarction, stroke and death in the long term. Preeclampsia, a condition in pregnancy, with raised blood pressure and increased protein in the urine is a leading cause of maternal and fetal deaths. Its treatment gives rise to large health care costs. Preeclampsia contributes to preterm birth, one of the leading causes of perinatal deaths in east London. It accounts for 65% of neonatal deaths and 50% of neurological disability in childhood. Around £900 million in extra costs for care of preterm babies per year in the NHS are linked to neonatal care. Preeclampsia, characterised by insulin resistance, widespread endothelial damage and dysfunction, coagulation defects and increased systemic inflammatory response, shares metabolic risk factors with cardiovascular disease. Obesity, dyslipidaemia and hypertension are independent risk factors for pre-eclampsia. Interventions that reduce cardiovascular events by modifying metabolic risk factors also have the potential to reduce the risk of pre-eclampsia.

Early identification of mothers at risk of preeclampsia will allow clinicians to deliver these targeted interventions in pregnancy, with the potential to prevent preeclampsia and modify cardiovascular risk in the long-term. Currently, low dose aspirin, recommended as a prophylactic measure reduces preeclampsia risk by only 10%. Simple, low-cost and effective acceptable interventions are required to reduce this risk further. Dietary interventions in pregnant women with metabolic risk factors such as obesity and insulin resistance are shown to reduce the risk of preeclampsia. But the existing studies are of poor quality and do not evaluate preeclampsia as the primary outcome. Furthermore, they focus on specific components of the diet, rather than modifying the overall dietary pattern. Mediterranean diet with high consumption of vegetables and fruits, olive oil and nuts and low consumption of red meat and processed food significantly reduces lipid levels and cardiovascular adverse events in non-pregnant high risk population. In pregnancy, the beneficial effect of the Mediterranean dietary pattern was observed in a large prospective study of nulliparous pregnant women with a 28% reduction in the risk of preeclampsia (RR 0.72; 95% CI 0.62, 0.85). These results need confirmation in a sound experimental study.

There is a need for an adequately powered randomised trial to evaluate the beneficial effect of lipid modifying diet in pregnancy that is simple, accessible and acceptable. The investigators hypothesis is that pregnant women with metabolic risk factors will derive benefit from dietary intervention in preventing maternal and fetal complications.