Detailed Anomaly Scan

Screening for Fetal Chromosomal Abnormalities. Second Trimester Fetal Anomaly Scan


Deborah explains the Detailed Anomaly Pregnancy Scan

More information about the Detailed Anomaly Scan:

This scan is probably the most important diagnostic scan that takes place in a pregnancy. The fetus is the correct size to have all the organs assessed so that the sonographer can see whether your baby has an obvious defect such as spina bifida or a cleft palate.

If you are concerned about chromosomal problems this scan can detect subtle markers that may suggest that your baby is at higher risk for these syndromes. Examples of these markers are thickened skin behind the neck, excess fluid in the kidneys, short arms or legs, bright areas in the heart or abdomen or cysts in the brain.

Remember that most babies are normal and that this scan provides reassurance to the majority of patients. It is also important to note that this is a screening test and that positive or negative findings detected during the scan cannot guarantee either outcome.

The purpose of this scan is:

  • To confirm intrauterine pregnancy
  • To determine fetal viability
  • To provide accurate gestational dating
  • To identify and measure fetal heart rate
  • To establish an accurate estimated due date
  • To determine the number of fetuses
  • To determine chorionicity and amnionicity if a multiple pregnancy
  • To examine for obvious uterine and ovarian pathology (visualisation of these structures is not always satisfactory in pregnancy)
  • To identify and examine some of the main organs in the fetus (the normality of these organs cannot be determined at this stage – however, if an obvious abnormality is identified you will be referred on to a fetal medicine specialist)

What to expect from a Detailed Anomaly Pregnancy Scan

The sonographer will put some gel on your tummy and move a probe over the skin. The image will come up on a big screen television so that you can see all the structures that are being examined.

The presentation of the baby and location of the placenta are established. Standard measurements are taken of the fetus’ body parts. This includes measurements of the head, abdomen and femur bone in the leg. The organs are identified one by one and the ultrasound markers are searched for. The amniotic fluid volume, placenta location and umbilical cord vessels are also assessed.

The gender of the baby can also be determined at this stage so feel free to ask the sonographer to disclose this information.