The obesity epidemic is growing worldwide and in the UK this is perpetuated with a third of women classified as overweight/obese in 2020. Many of these woman are of childbearing age and go on to have high risk pregnancies which are often complicated by gestational or pre-existing (type 2 diabetes mellitus (GDM, T2DM). Bariatric surgery is the most successful treatment of sustainable weight loss and is associated with a reduction in rates of GDM, pre-eclampsia, delivery of large babies but increased risk of delivery of small babies and preterm delivery. The aims of the study are to investigate the maternal and fetal/neonatal, biophysical and biochemical, intra-uterine environment and postnatal profile of pregnancies: 1. affected by maternal obesity and/or GDM/T2DM compared to pregnancies with normal maternal body mass index (BMI). 2. with previous maternal bariatric surgery compared to pregnancies without previous bariatric surgery but matched for maternal pre-surgery and early pregnancy BMI.