This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ecotopic Pregnancy, Subject name: Gynaecology & Obstetrics
A woman attends antenatal clinic with complaint mild pain in lower abdomen on left side, her periods are regular and UPT was positive at home. A TVS was done and uterine cavity is empty, and no adnexal mass is seen. Her serum beta HCG is 700 IU/L. what is the next step? 
Select and explain. 
A. Give single dose of methotrexate, B. Perform laparoscopy, C. Perform serum beta HCG after 48 hr, D. Perform serum Beta HCG after 7 days
C: Perform serum beta HCG after 48 hr
Answer: C: Perform serum beta HCG after 48 hr 
Explanation: Ans. C. Perform serum beta HCG after 48 hrThis is a case of pregnancy of unknown location. The beta HCG value is less than the discriminatory zone of 1500mIU/ml on TVS. "With these PULs, serial b-hCG level assays are done to identify patterns that indicate either a growing or failing IUP. Levels that rise or fall outside these expected parameters increase the concern for ectopic pregnancy. Thus, appropriately selected women with a possible ectopic pregnancy, but whose initial b-hCG level is below the discriminatory threshold, are seen 2 days later for further evaluation. Trends in levels aid diagnosis."