Objective: To assess the reliability of the most widely used clinical metho
ds for predicting or confirming ovulation.
Methods: We monitored spontaneous cycles in 101 infertile women using basal
body temperature (BBT), transvaginal ultrasound, a urinary stick system fo
r LH surge, and three serum progesterone measurements in the midluteal phas
e. Transvaginal ultrasound monitoring was standard for ovulation detection
and sensitivity. We calculated specificity and accuracy of each method comp
ared with that standard.
Results: Follicular development and ultrasound evidence of ovulation were c
onfirmed in 97 of 101 cycles (96%). Urinary LH surge preceded follicular ru
pture assessed by ultrasonography in all cycles and showed concordance with
ultrasound-evidenced ovulation in 98 of 101 cases. The timing of BET nadir
had wide variability, and BET and ultrasonography agreed in a similar perc
entage of cases (74%). Midluteal serum progesterone assessments showed ovul
atory values in 93 subjects, and ovulation was concordant with ultrasonogra
phy in 90 subjects.
Conclusion: Urinary LH was accurate in predicting ovulation with ultrasonog
raphy as the standard for detection, but time varied widely. The nadir of B
ET predicted ovulation poorly. The BET chart was less accurate for confirmi
ng ovulation, whereas a single serum progesterone assessment in midluteal p
hase seemed as effective as repeated serum progesterone measures. (C) 2001
by The American College of Obstetricians and Gynecologists.