Rates of among women of reproductive age are rising such that 1 in 5 women in the UK are obese at antenatal booking. Female obesity is associated with reduced fertility including ovulatory dysfunction and increased time to pregnancy. Obese pregnancy is associated with increased pregnancy loss and stillbirth, and with increased risk of major pregnancy complications including gestational diabetes and preeclampsia. In addition there are short and long-term complications for the offspring including macrosomia, shoulder dystocia and risk of later obesity and cardiometabolic disease. Results of intervention studies to improve fertility rates and reduce pregnancy complications in obese women will be discussed including weight loss and lifestyle interventions, bariatric surgery and pharmacological interventions such as metformin. Considerations for optimal management of obese women prior-to and during pregnancy will be discussed, drawing upon our own experience from running an antenatal metabolic clinic for very severely obese women (BMI > 40) and from the evidence presented in our recently developed Royal College of Obstetrics and Gynaecology Green Top Guideline for management of obese pregnancy.