What is a Dating/Viability scan?

This is an ultrasound examination that is usually carried out vaginally but can be done abdominally at around 7 weeks onwards. It aims to determine the number of fetuses present and whether the pregnancy is progressing normally inside the uterus. This scan is useful for women who are experiencing pain or bleeding in the pregnancy and those who have had previous miscarriages or ectopic pregnancies.

Sometimes called a Viability Scan or Dating Scan this may be the first pregnancy scan you will have. It may also be useful for women who do not know the date of their last menstrual period.

The dating scan can show the gestation sac (indicating a healthy pregnancy) and the embryo. The fetal heartbeat is normally visible from 7 weeks onwards. It is usually done vaginally to allow a clearer picture of the baby. This is neither painful nor uncomfortable and is the best way to obtain clear images in early pregnancy.


How is this scan performed?

Most early pregnancy ultrasounds are performed with external and internal/vaginal approaches. The small internal vaginal scanner causes less discomfort than a smear test examination. It almost always gives clearer and more accurate information about early pregnancy development. 


Will my baby be ok during the scan?

Ultrasound can be safely used during pregnancy. Having a vaginal scan does not impact on your baby’s well being.

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What will I find out at this scan?

Dating scans also reveal other important information such as:

  • the number of fetuses and gestation sacs

  • the presence of a heart beat

  • the size of the fetus, from which the gestational age is estimated

  • unusual features of the uterus such as the shape or the presence of fibroids


How long will the scan take?

The scan can take up to 30 minutes to complete.