4.4 Surveillance in increased risk pregnancies

Serial fundal height measurements are insufficient to monitor a pregnancy identified as at increased risk. Instead, serial ultrasound scans are recommended through third trimester until delivery

• Frequency of serial scans should be 3 weekly, commencing at 28 weeks’ gestation. Scan frequency may need to be increased if growth rate or Doppler findings are abnormal (but interval should not be less than 2 weeks as scan error then is likely to be greater than the expected growth increment) ³. 


• At each scan, EFW should be calculated and plotted on the customised growth chart


• While measurement and recording of individual fetal biometry parameters (e.g. HC – head circumference,  AC – abdominal circumference,  FL – femur length) is standard practice, their plotting is not required and even discouraged to avoid confusion. Customised charts are based on birthweight derived fetal weight norms, and no neonatal standard exists for any of the individual ultrasound biometry measurements.