<prompt> Plasma levels of hCG during pregnancy doubles every: September 2010Daily2 days4 days6 days  <response>: Ans. B: 2 days Pregnancy tests may be used to determine the bility of a pregnancy. Serial quantitative blood tests may be done, usually 2-3 days apa. Below an hCG level of 1,200 mIU ml the hCG usually doubles every 48-72 hours, though a rise of 50-60 is still considered normal. Failure to increase normally may indicate an increased risk of miscarriage or a possible ectopic pregnancy. 