Anomaly Ultrasound Scans

What is the Fetal Anomaly Scan?

This is a detailed scan carried out at 20-24 weeks of pregnancy. It is the second routine scan appointment in the pregnancy and is aimed at assessing each part of the baby’s body, measuring the baby’s growth, determining the position of the placenta and assessing the amount of amniotic fluid around the baby.

The main objectives of this visit are:

  •  Accurate assessment of the fetal wellbeing
  • Diagnosis of major fetal abnormalities
  • Accurate assessment of the placenta
  • Accurate assessment of the amniotic fluid

How much time will the appointment take?

The scan appointment is for 60 minutes but in some circumstances, it may take more than an hour depending on the position of your baby and the adequacy of views obtained on the ultrasound scan.

Do I have to have a full bladder for the scan?

No, you do not need to have a full bladder for this appointment.

How will the scan be carried out?

The ultrasound examination will be carried out through your abdomen (transabdominal). Sometimes it may be necessary to carry out an internal examination (transvaginal) if the necessary views to complete the scan cannot be obtained by abdominal scanning.

What if I am deemed to be high-risk?

If the result of the anomaly scan is abnormal, the pros and cons of further management options will be discussed with you, which include cell free DNA testing by taking a blood sample from the mother or an invasive test such as amniocentesis. The result may only suggest further monitoring of the pregnancy.

What are the additional assessments?

  • Assessment of cervical length to check for risk of premature birth can be carried out at the same visit as the scan.
  • Ultrasound (Doppler) examination of blood vessels in the mother (uterine arteries) for assessment of placental function can also be carried out at the time of the scan.
  • In some pregnancies such as mothers with Diabetes Mellitus or those with epilepsy, a detailed fetal heart examination (echocardiography) is recommended.