It is believed that follicular development and ovulation is suppressed during the early period of gestation in humans. In this report, we describe a patient who underwent ovarian hyperstimulation following a "presumed" menstrual bleeding. The case illustrates that the ovaries during early pregnancy seem to respond normally to exogenous gonadotrophin stimulation. Despite ongoing pregnancy, the high plasma concentrations of gonadotrophins have rescued pituitary and ovarian insensitivity. Normal follicular development and even ovulation are allowed to occur. Moreover, it is mandatory to preclude pregnancy before commencing superovulation and assisted reproductive technology.