TIME-INTERVAL FROM HUMAN CHORIONIC-GONADOTROPIN (HCG) INJECTION TO FOLLICULAR RUPTURE

The aim of this study was to estimate the time interval from human cho rionic gonadotrophin (HCG) injection to follicular rupture, Furthermor e, it was observed whether there was any effect on the pregnancy rate if the insemination was performed at the time of follicular rupture, I n a programme of intrauterine insemination 37 consecutive cycles in 32 patients were monitored after stimulation with clomiphene citrate. HC G was administered by i.m. injection when a leading follicle of at lea st 18 mm in diameter was observed sonographically. All patients were m onitored by sonography with 1 h intervals from 32 h after HCG injectio n until the first rupture of a follicle, Insemination was performed im mediately after the first follicular rupture, The pregnancy rate was 1 6% (5/32). In 66%, the largest follicle was the first to rupture, The mean time interval from HCG administration to first follicular rupture was 38.3 h (SEM = 0.54; range = 34-46). Our findings support the conc ept that ovulation occurs about 38 h after HCG administration, The pre gnancy rate was within the normal range, although insemination was per formed at the time of follicular rupture, The largest follicle was not always the first to rupture.