An assay of serum samples from a normal woman with a history of regular 28-day cycles indicates that, during the last 12 hours, there has been a peak in the serum concentration of estradiol-17 B in the absence of any detectable progesterone. Which of the following can be expected to occur within 3 days?
a. cessation of menstruation
b. decreased basal body temperature
c. onset of menstruation answer C
e. regression of the corpus luteum
Answer is C