For an abdominal dating ultrasound, you will need to have a full bladder. Your sonographer will let you know if this is needed. You may also like to ask your friends who have had a positive experience and to see who they would recommend in terms of having firsthand experience. But by the time the baby has developed to full term, this rate increases to around BPM. This is because although every little embryo is unique, there are still defining characteristics of development which apply to all embryos at particular stages of early gestational development. The screening test for Down's syndrome used at this stage of pregnancy is called the "combined test".
In some situations, such as when the scan is completed before 10 weeks of gestation or you are overweight, you may also need a vaginal scan.
WHEN TO DO A DATING SCAN
Questions to ask your doctor about tests and scans. What will the dating scan involve? In the meantime, we will continue to update and add content to Pregnancy, Birth and Baby to meet your information needs. Tell us a little bit about your child. When is the best time to get a dating scan done: Pregnancy Week by Week Take a look at each week of your pregnancy, from conception to birth, with our comprehensive email newsletters. Checkups, scans and tests during pregnancy.