Ultrasound has been an integral part of pregnancy care since the 1970s with universal uptake in the 1990s. But how often should you be scanned and are there any side effects?
Each scan should have a purpose, just like a blood test or examination. Essentially, in pregnancy, there are four common scans.
An early pregnancy or ‘dating’ scan.
For women who conceive via IVF this is usually done to confirm a successful pregnancy. For natural conceptions this can occur either at your first antenatal visit with your private obstetrician in their rooms or at a private ultrasound clinic as arranged by your GP. These scans are designed to confirm the viability of the pregnancy, check if it is a single or multiple pregnancy and accurately date the pregnancy.
The 12 week scan
This is another opportunity to confirm an ongoing heartbeat and double check the dates however this scan, when performed thoroughly, has the ability to screen for conditions such as Trisomy 21 (Down syndrome) and some other common chromosomal conditions. A general review of anatomy should be performed at this scan too, with 40% of structural abnormalities seen this early.
The 20-22 week scan
This is the ‘big scan’. Be prepared to be in the scan clinic for 45 minutes to an hour. A full thorough assessment of all of the anatomy of the baby is checked at this scan. Some parents choose to find out the gender of their baby at this scan.
A third trimester scan
Not all doctors recommend a third trimester scan. Certain medical or obstetric conditions require a scan at around the 32-34 week mark (for example a low lying placenta, diabetes, fetal abnormality) but some obstetricians ask all of their patients to have a scan at 32 weeks to monitor the growth of the baby.
Many private obstetricians also have good quality ultrasound machines in their rooms and will scan you at each antenatal visit. These scans are simple and designed to confirm the presence of the baby’s heartbeat but also enable the obstetrician to quickly view parameters of foetal wellbeing such as the level of water around the baby.
Dr Vicki Woodward is an obstetrician and gynaecologist at Frances Perry House. Click here to view the specialists accredited to provide antenatal and postnatal care at Frances Perry House.