Ultrasound scans are considered to be safe for you and your baby when performed by trained professionals.
However, sometimes, having a scan can cause unnecessary worry.
However, conception doesn't actually occur until around 14 days after your LMP, or later if your cycle is longer than 28 days. Multiple pregnancy: antenatal care for twin and triplet pregnancies CG129.
You may have calculated the length of your pregnancy from the first day of your last menstrual period (LMP). If you prefer, you can have a private screening test. As well as the combined test, most private healthcare clinics offer non-invasive prenatal testing (NIPT), which is the most accurate (up to 99 per cent) screening test for Down's Syndrome. 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.