Time schedules of intrauterine insemination after urinary luteinizing hormone surge detection and pregnancy results.

A urinary luteinizing hormone (LH) test (LH Color, Organon, Oss, The Netherlands), was used to time intrauterine insemination in 177 cycles. Morning and evening urine samples were tested. In 58 women (33%) the test was positive in the morning urine sample. Fifteen of these patients were inseminated 8-10 h thereafter and one patient (6.7%) conceived. The remaining 43 women were inseminated the following day, 25-31 h after LH detection, and seven pregnancies (16.3%) ensued. In 119 cycles showing a positive urinary test in the evening sample, insemination was performed the next day, between 17 and 23 h after the LH surge, and 18 patients (15.1%) became pregnant. Statistical analysis showed no significant differences in pregnancy rates between the three different schedules, or in the time of insemination between conceptional and non-conceptional cycles within each group. Most ovulations occurred between 16 and 28 h after the positive test was observed. These findings suggest that while the lifespan of the gametes allows a relatively long period for fertilization, from 8 to 31 h after urinary LH surge detection, better results may be expected when inseminating about 24 (+/- 6) h after the positive test.