Ultrasound defining the fetus as a patient

Developments in fetal medicine are having a profound effect on how pregnancies are managed and have resulted in the fetus becoming a fully fledged patient in its own right. These developments for obstetricians and specialists in fetal medicine will have potentially great benefits in the long term, largely thanks to improvements in ultrasound imaging, which enable obstetricians to diagnose structural and functional abnormalities in the fetus more accurately.

Two dimensional ultrasound imaging is the mainstay of obstetric practice in the United Kingdom. Most pregnant women are offered, and receive, two ultrasound scans as a matter of routine. The first is carried out in the first trimester, with the principal aim of dating the pregnancy accurately. The second is carried out around 20 weeks and is designed to examine the fetus for structural anomalies. In recent times, the role of ultrasound has extended into diagnosing functional abnormalities and assessing the risk for such complications as preterm delivery, pre-eclampsia, and growth restriction.12

Detection rates for abnormalities have risen steadily, and most units would now expect to identify a large number of the major structural abnormalities, such as spina bifida, abdominal wall defects (exomphalos), skeletal dysplasias etc.3 Skilled practitioners using the best equipment can now identify and delineate structural defects in the fetus from as early as 12 weeks, and many specialists now think that scanning for anomalies can be brought forward in pregnancy.4 Some abnormalities, however, cannot be detected until 20 weeks, and currently the second trimester scan therefore …