Inaccurate dating of the pregnancy
The point of the scan is to work out how many weeks pregnant you are. Ectopic pregnancy and miscarriage: diagnosis and initial management CG 154.
You may have calculated the length of your pregnancy from the first day of your last menstrual period (LMP).
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.
Keep it with your maternity notes so your midwife and anyone else involved in your care can see it. This measurement, known as the crown rump length (CRL), is very accurate in the first trimester. 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 sonographer will put some gel on your tummy and move a small hand-held device (transducer) over your skin to get views of your baby. It won't hurt, although you may feel a little pressure on your tummy. If your womb (uterus) is very deep in your pelvis, or if you're overweight, you may be offered a vaginal scan, which can get a closer view of your baby.
Your baby's head, limbs, hands, and feet can be seen, as well as his abdominal wall and some organs, such as his stomach.