How long after delivery do HCG levels go back to normal?

According to Mayo Medical Laboratories, the level of human chorionic gonadotropin will fall to half of its pregnancy concentration in the body within 24 to 36 hours of birth, miscarriage or abortion. From this half-life speed, normal levels should be achieved within roughly one or two weeks.

This rate of return to the baseline means that the concentration of HCG in a mother postpartum can be used to monitor whether or not the child left behind any remnants of pregnancy. The placenta or any other developmental pieces of the child cause the concentration of HCG to remain higher than normal longer than expected, which can be a red flag to medical professionals, according to Mayo Medial Laboratories.