Ultrasound for dating bokks rules of dating
It records high-frequency sound waves that create an image (see Reference 4).
Normally, ultrasounds before until week 4 of pregnancy shows nothing in the uterus and serve no purpose.
This means that accurate dating reduces your chance of having your labour induced because your baby is thought to be overdue.
Finding out about having twins early in pregnancy also gives you more time to prepare for the birth and for your doctor and midwife to plan your care. Nearly all scans after 10 weeks can be done through your tummy, and most units ask you to arrive with a full bladder.
The dating scan isn't designed to look for more subtle abnormalities, though.
That will happen at your next routine scan at about 20 weeks However, some major problems can be seen at your dating scan, such as issues with the umbilical cord or with your baby's skull or abdominal wall.
You may need a second scan to check the first scan's findings.
The dating scan will also show if you're expecting twins, triplets, or more.