Know-how: Antenatal Scans

Ultrasound scans: what, when and why?
An ultrasound scan is a completely non-invasive way of checking that the fetus is growing correctly and that your womb is in good health. That is, it is a way of monitoring you without having to do an internal examination of any kind.
You will be asked to lay on a bed and allow the radiographer or doctor to access your bump. You don't have to take all your clothes off, but wearing a skirt or trousers that are easy to undo or loosen, will help. You will have a cold but harmless gel rubbed onto your tummy to enable the scanner to run more smoothly over your skin. The scanner has a roller surface which acts like a sensor, sending sound waves through the tissue to collect information that is then translated into an image bounced back and portrayed on a screen. Research and decades of use of this procedure suggest that this in no way harms your baby.
The quality of scanning machines has improved so that more detail can now be picked up through improved frequency performance. Sometimes, if the radiologist feels that you can see what sex the baby is by looking at the screen and you do not wish to know, then he or she may advise you not to take a peak!

Dating scan Unless you have a history of gynaecological problems or there has been severe bleeding and suspected miscarriage, the first scan you are most likely to have is the dating scan. Most UK health authorities offer this at around 11 to 13 weeks. At this time, the measurements of your baby are taken and a more accurate due date is set for the birth. At this stage it can also be confirmed whether you are carrying one or more babies. Some possible health conditions can be spotted at this time also.

Nuchal translucency scan This scan can help assess the likelihood of your baby having Down's Syndrome but is not routinely offered to younger women. Beyond 35 years of age, you may be offered this scan, but if not, ask your GP, at the time of having your pregnancy confirmed, if you can have it (if you so choose). This scan measures the fluid at the back of the baby's neck and the nasal bone's development, indicators of the possibility of Down's. It is less invasive than a blood test and amniocentisis and carries no risk of miscarrriage (where amnio does). This scan needs to be performed during the first half of a pregnancy and can be carried out privately if you feel the need for it and your hospital or doctor do not.

Fetal anomaly scan This scan is a routine scan (like the dating one) and is usually carried out at about 20 weeks. This will check measurements again to ensure that the due date is as accurate as possible, and will also be used to check the growth and performance of various organs including the heart chambers.

Other scans You can get a '4D' scan of your baby which shows an amazing amount of detail. These are usually only available privately but you should be able to get information about local clinics offering the service quite easily from your antenatal clinic.
Additionally, if your GP, midwife or obstetrician feel there is any development which needs to be monitored during your pregnancy - if you have fibroids, or are expecting more than one baby, for example - you may be sent for extra scans over the 40 week period. These are nothing to worry about and are there to make sure you and your baby are safe and well.

Photographs Most clinics and hospital will offer the chance to get a screen grab image of the baby for you to take home. They will probably charge a small fee, and might only offer this service at one rather than both the routine scans, depending on what your own local services can accomodate.

The only downside to scans is, that because you are asked to attend a scan appointment with a full bladder (this positions the womb more favourably for viewing), it can get harder to cross your legs when you are further into your pregnancy. Make sure you know where the nearest loo is for when you come out of the scan session!