How accurate are dating scans at 12 weeks Stranger cam
Ultrasound scans use sound waves to build a picture of the baby in the womb.
The scans are completely painless, have no known side effects on mothers or babies, and can be carried out at any stage of pregnancy.
Traditionally the last menstrual period has been used to date a pregnancy, but this may be highly inaccurate.
A simple formula is to take the first day of the menstrual period, subtract three months and add one week.
Dating a pregnancy accurately at the earliest possible time is important.
In a normal pregnancy it does not matter what the dates are, but if anything should go wrong it becomes very important as to what treatments may be prescribed.
Even dating scans can be inaccurate for the due date, but they are never as inaccurate as using the menstrual period.
It's very exciting to "see" your baby in the womb, often moving his or her hands and legs.
Having a scan in pregnancy is usually a happy event, but be aware that ultrasound scans may detect some serious abnormalities, so you should be prepared for that information.
The purpose of the dating scan is to: Some abnormalities may also be detected at this scan, such as neural tube defects (spina bifida is a type of neural tube defect).
This depends on whether you have agreed to have the screening and when the scan takes place.