Dating and Viability Scan
What information is gained from an early pregnancy scan?
- The location of the pregnancy
- The number of embryos in the uterus
- The presence of a heart beat in the embryo
- The length of the embryo (this will establish the dating of the pregnancy)
- The presence of uterine fibroids or ovarian cysts in the pelvis
Why might an ultrasound be required in the first 11 weeks of pregnancy?
- Abdominal pain
- Vaginal bleeding
- Uncertain menstrual dates
- Previous recurrent miscarriage
- Previous ectopic pregnancy
- Women at risk of multiple pregnancies (eg pregnancy following ovulation induction therapies)
How accurate is pregnancy dating?
A dating ultrasound of the length of the embryo when performed at 7-11 weeks gestation is accurate to within about 3 days. Beyond this time the accuracy reduces due to flexion (bending) of the fetus and individuals growth variance.