Dating scans are offered between 10 and 14 weeks to literally ‘date’ the pregnancy and check how many babies you are carrying.
An ‘anomaly’ scan is offered between 18-20 weeks
You will be asked to drink at least a litre of water before the scan to fill up your bladder; this pushes up the uterus to give a clearer picture. You’ll then have gel rubbed onto your belly and a hand-held scanner passed smoothly backwards and forwards over your skin. If you look at the monitor, you’ll see a picture of your baby on the screen.
If the picture is difficult to make out, the radiographer will explain it. She will also measure the baby to check she is measuring the right size for your dates. She may use this information to give you a new estimated date of birth, which is usually more accurate than the original date.
You can ask for a copy of the scan picture (most hospitals make a small charge for this) and some hospitals will let you purchase a video recording too.
Around 90% of multiple pregnancies are diagnosed by an early ultrasound at around 12 weeks. Carrying twins or more can be more complicated than carrying a single baby and your health care team will want to monitor your progress closely, so expect to have frequent check-ups. You’ll be offered more frequent ultrasound scans too, so the growth and development of your babies can accurately be assessed.
You may find that some of the early pregnancy symptoms you have such as morning sickness and tiredness are exaggerated – compared to if you were carrying a single baby. As your pregnancy progresses, you are likely to find that extreme tiredness and an increased need to rest means you have to stop work earlier than you might otherwise have done.
When there are multiple babies there is a higher risk of complications during labour and birth so you will need to have a hospital delivery. Twins are often born at around week 37 and although it is perfectly possible to have them naturally, it is not unusual for twins to be born by Caesarean.