Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women.

OBJECTIVE To describe the LH surge variants in ovulating women and analyze their relationship with the day of ovulation and other hormone levels. DESIGN Secondary analysis of a prospective cohort observational study. SETTING Eight natural family planning clinics. SUBJECTS Normally fertile women (n = 107) over 283 cycles. INTERVENTION(S) Women collected daily first morning urine, charted basal body temperature and cervical mucus discharge, and underwent serial ovarian ultrasound. MAIN OUTCOME MEASURE(S) Urinary LH, FSH, estrone-3-glucuronide (E3G), pregnanediol-3α-glucuronide (PDG), and day of ovulation by ultrasound (US-DO). RESULT(S) Individual LH surges were extremely variable in configuration, amplitude, and duration. The study also showed that LH surges marked by several peaks were associated with statistically significant smaller follicle sizes before rupture and lower LH level on the day of ovulation. LH surges lasting >3 days after ovulation were associated with a lower E3G before ovulation, a smaller corpus luteum 2 days after ovulation, and a lower PDG value during the first 4 days after ovulation. CONCLUSION(S) In clinical practice, LH profiles should be compared with the range of profiles observed in normally fertile cycles, not with the mean profile.