Detailed scan

All women are offered a detailed or 'anomaly' scan between 18 weeks and 0 days and 20 weeks and 6 days. It's called the anomaly scan because it checks for structural abnormalities (anomalies) in the baby.

We screen for 11 specific conditions in accordance with the fetal anomaly screening programme:

  • Anencephaly
  • Spina bifida
  • Cleft lip
  • Diaphragmatic hernia
  • Gastroschisis
  • Exomphalos
  • Seven serious cardiac abnormalities
  • Bilateral renal agenesis
  • Lethal skeletal dysplasia
  • Edwards' syndrome (Trisomy 18)
  • Patau's syndrome (Trisomy 13)

The scan will also check the position of the placenta.

Ultrasound findings which are not normal

For the majority of women, the 18-20 week scan is a reassuring and memorable experience, but sometimes problems are found. If any abnormalities are detected during the scan the sonographer will discuss these with you and arrange for you to see a fetal medicine midwife or doctor at the earliest opportunity.

Some findings may not be significant and will resolve themselves. Others can forewarn of problems that would otherwise not be detected until birth or even infancy. Some information can cause considerable anxiety and can lead parents to consider options regarding continuation of the pregnancy.

It must be remembered that a normal scan does not guarantee fetal health and well being.

It is important to remember that only some abnormalities can be detected by scan; others are difficult to detect and therefore may be overlooked by scan, while some do not develop until later in the pregnancy or after birth.