Temporal relationship and reliability of the clinical, hormonal, and ultrasonographic indices of ovulation in infertile women.

To assess ovulatory function, 50 infertile but "normally" ovulating women were monitored closely during a single menstrual cycle with daily measurements of serum estradiol, progesterone, and LH (morning and evening urinary LH by standard radioimmunoassay and morning urinary LH by enzyme-linked immunosorbent assay); transvaginal ultrasound; basal body temperature (BBT) recording; and cervical mucus. All 50 cycles, 40 spontaneous and ten induced with clomiphene citrate, were ovulatory. Follicle rupture was confirmed by ultrasound in 47 cycles (94%), whereas three patients fulfilled the diagnostic criteria for luteinized unruptured follicle syndrome. Follicle rupture occurred on day +1 in three, on day +2 in 34, and on day +3 in ten of the ovulatory cycles. Urine LH testing correlated well with the serum LH peak, particularly in the evening urine, and predicted ovulation in all patients. The initial periovulatory rise in serum progesterone occurred on the same day as the LH surge (day 0) in 30%, on day +1 in 40%, on day +2 in 22%, and on day +3 or later in 8% of the cycles. The rise in BBT corresponded to an increase in serum progesterone to 5 ng/mL or greater. Neither the BBT nor cervical mucus was reliable in predicting ovulation.