The morphology scan is a routine antenatal screening test that is usually performed at between 18 and 20 weeks’ gestation. You require a referral from your GP or obstetrician. Scans may be done at any radiology practice that has a trained ultrasonographer or a specialised Maternal-Fetal Medicine (MFM) Centre. Be careful of bulk-billing centres; you often get what you pay for.
The scan is performed by a specially trained ultrasonographer and usually takes 30 to 60 minutes. Your partner is usually welcome to attend this scan.
What if a problem is found?
You should book to see your obstetrician soon after your scan. The results of the scan will be explained and further investigations will be organised. If you have a scan at an MFM centre, the results will be explained by the specialist on duty.
The commonest abnormality found is a low-lying placenta. This will require a re-scan at 32 to 34 weeks. By this time, in most cases, the placenta is nowhere near the cervix.
Is ultrasound safe in pregnancy?
Ultrasound has been used in pregnancy since the 1970’s. It has gained in popularity in the subsequent decades. There are no known harmful effects of ultrasound despite intensive use in pregnancy. Part of the ultrasound scan requires the use of power Doppler (for heart images) and colour Doppler (for blood flow though umbilical vessels, the fetal brain and the fetal liver). These types of ultrasound are used for just 1 or 2 minutes only. Theoretically, harm can come from these but it requires the ultrasound probe to be held in the one position for more than 20 minutes. This will never occur in any ultrasound scan and there have been no recorded harmful effects from the use of Doppler.