When an intrauterine pregnancy is not visualized on ultrasound with hCG above the discriminatory zone, it is presumed that the gestation is non-viable or ectopic. In these circumstances a dilatation and curettage is carried out to confirm intrauterine pregnancy. Dilatation and curettage is performed under general anaesthetic, the cervix is dilated and curettings are taken by scraping tissue from the lining of the uterus.