A female has history of 6 weeks amenorrhoea, USG shows no sac, serum beta HCG-1000 IU/L. What would be the next step in management of the patient?

In normal intrauterine pregnancy the level HCG doubles every 48 hours whereas in ectopic pregnancy the level of HCG shows a slow rise or it plateaus. Since the USG in this patient does not show a sac and the level of HCG is low its level should be repeated after 48 hours to exclude ectopic pregnancy. In normal pregnancy at 5-6 weeks of gestation, a gestational sac is visible on ultrasound. A beta-hCG level of 6500 mU/mL with an empty uterine cavity by transabdominal ultrasound is highly suspicious for an ectopic pregnancy. A beta-hCG value of 2000 mU/mL or more can be indicative of an ectopic pregnancy if no products of conception are detected within the uterine cavity by transvaginal ultrasound. Ref: Rogers V.L., Worley K.C. (2013). Chapter 19. Obstetrics & Obstetric Disorders. In M.A. Papadakis, S.J. McPhee, M.W. Rabow (Eds), CURRENT Medical Diagnosis & Treatment 2014.