Evaluation of ovulation and corpus luteum function using measurements of plasma progesterone

To develop a practical yet statistically valid means of indicating ovulation and adequacy of corpus luteum function concentrations of plasma progesterone (P) were measured daily during the luteal phase of 30 normal and abnormal menstrual cycles. During a normal cycle any 3 P measurements taken from 11 days before the first day of the following menses (M) to Day M-4 gave a total equal to or greater than 15 ng/ml. An abnormal cycle was considered one in which the total P (for 3 measurements) was less than 15 ng. Individual levels were often at 3 ng/ml in normal cycle and above 3 ng/ml in abnormal cycles indicating that the single P measurement proposed by Israel et. al. would not always be valid.