For many parents, this is the appointment they have been counting down to, the scan where you can find out whether you are expecting a boy or a girl, if you would like to know.
It is properly called the gender and foetal wellbeing scan, and alongside the reveal it gives a genuine check of how your baby is growing. Here is what to expect.
01What a gender scan is
A gender scan is an ultrasound examination carried out mid-pregnancy, usually from 16 to 18 weeks at our clinic. It is a non-invasive scan that, alongside determining your baby’s sex, checks their overall development and wellbeing.
No scan is 100% definitive, and your baby’s position on the day can affect visibility, but for most parents, it is an exciting milestone and a real chance to connect with the baby growing inside them.
Whether or not you want to know the sex, this scan is a proper wellbeing check in its own right. That part is never skipped.
The pregnancy scanning team
02What to expect on the day
The appointment is straightforward and comfortable.
- A specialist sonographer applies gel to your abdomen and gently moves a transducer across your skin
- The transducer sends sound waves that build a live image of your baby on the screen
- You will see your baby moving, and in most cases, find out if you are having a boy or a girl
- The appointment usually takes 20 to 30 minutes
How the technology works, and why it is considered safe, is covered in more detail in our article on the importance of ultrasound.
03What else the scan checks
The sex reveal tends to be the headline, but the scan is a genuine check-up in its own right.
- Foetal biometry, measurements used to estimate your baby’s weight and plot it on a growth chart.
- Amniotic fluid, checked for volume and quality, an indicator of your baby’s wellbeing.
- Placental location, including checking for conditions such as placenta praevia, which can affect delivery planning.
- Cervical assessment, usually done over your abdomen; a transvaginal scan is only used, with your consent, if something needs a closer look.
- A basic anatomy check, a preliminary look, not a substitute for the more detailed anomaly scan between 18 and 24 weeks.
04Keeping the sex a surprise: it’s your choice
Not everyone wants to know before birth, and that is entirely your call. If you would rather keep it a surprise, simply tell your sonographer before the scan begins. They will make sure the sex is never mentioned, on screen or in conversation.
05How accurate is a gender scan?
Gender scans are usually very reliable, though, like any scan: they are not 100% certain. One published study found accuracy of around 87.6% for boys and 96.8% for girls.
accuracy for boys, in one published study
accuracy for girls, in the same study
View as table
| Statistic | Value |
|---|---|
| accuracy for boys, in one published study | 87.6% |
| accuracy for girls, in the same study | 96.8% |
Source: Published accuracy study of ultrasound fetal sex determination (see references).
If the scan cannot determine the sex, often simply because of how your baby is lying. We can offer another scan a little later to try again.
06After your scan
You can go straight back to your normal activities. Your sonographer explains the findings and gives you images of your baby. If anything needs a closer look, they will explain the next step, typically the anomaly scan, which continues the detailed anatomy check from 18 weeks.