You might get a transvaginal scan if: You have a history of preterm labour and your doctor wants to check your cervix mouth of uterus and birth canal. You are overweight , and an abdominal scan cannot deliver clear images. Your doctor suspects you have a low lying placenta, called placenta praevia. Depending on when in your pregnancy it takes place, a TVS can be used to: See whether you’re pregnant with one or more babies Check that your pregnancy is progressing normally in the uterus Evaluate the reason for any abdominal pain, spotting or bleeding Rule out an ectopic pregnancy Sometimes a TVS is done for non-medical reasons, for example to date your pregnancy if you are not sure about the first day of your last menstrual cycle. How should I prepare for a TVS? Many women find a vaginal scan more comfortable than an abdominal one , because you don’t need a full bladder during the procedure! You will need an empty bladder for this scan because a full bladder can get in the way of a clear picture of your baby.