To examine the impact of maternal obesity on completion of fetal anomaly screening.Methods:
A retrospective analysis of 500 anomaly scans (19+0-21+6 weeks) was included. Women were categorised according to the World Health Organisation (WHO) body mass index (BMI) classification: normal weight (18.50-24.99 kg/m2), overweight (25.00-29.99 kg/m2), obese class I (30-34.99 kg/m2), obese class II (35.00-39.99 kg/m2) and obese class III (≥40.00 kg/m2). A fetal anomaly imaging scoring system was developed from the National Health Service (NHS) Fetal Anomaly Screening Programme standard to evaluate scans.Results:
Image quality deteriorated as BMI increased and was significantly different across the BMI categories (P<0.001). Performance was poorest in imaging of the fetal chest and was significantly different across BMI categories (P<0.001). In obese class III, 33% of four-chamber cardiac views and 38% of outflow tract views were not obtained. In total, 119 women (23.6%) had an incomplete scan. In obese class III, 44.1% of scans were incomplete compared with 10.2% in the normal BMI category (P<0.001). Of 117 women attending for repeat scans, 78.6% were complete, 11.1% were incomplete, 6.8% were advised to re-attend and 3.4% were referred to Fetal Medicine.Conclusion:
Maternal obesity has a significant impact on completion of fetal anomaly screening.