These risks include: 1. Ectopic pregnancy - This occurs in 1% of pregnancies. This usually presents with vaginal bleeding with or without moderate to severe abdominal pain. This is a medical / surgical emergency.
2. Miscarriage - This occurs in 10-15% of pregnancies. It may present with vaginal bleeding with or without abdominal pain. It may also not be associated with any symptoms.
An ultrasound scan is required if there is vaginal bleeding and / or abdominal pain as it is required to confirm that the fetus is within the uterus (i.e. not an ectopic pregnancy) and the heart beat of the fetus is present.