Impact of maternal obesity on procedure of mid-trimester anomaly scan.

A maternal body mass index (BMI) >or= 30 kg/m(2) increases the risk of giving birth to a baby with an anatomical congenital anomaly. Such anomalies can be detected prior to birth using ultrasound as a screening modality. This study documents the impact of maternal obesity on image quality and service provision of the mid-trimester fetal anomaly scan. A prospective observational study of 327 pregnant women demonstrated 21% of women were obese. In this group, sub-optimal views of fetal anatomy and consequent requirement for re-appointment were all significantly greater. We conclude that obese women require information regarding reduced sensitivity of the 20-week anomaly scan. The increasing prevalence of obesity will have a significant effect on resources for maternity ultrasound departments.