The problem of polyspermy in in vitro fertilization.

Polyspermy is a potential complication of attempts at in vitro fertilization. Nine polyspermic oocytes were identified among 169 oocytes obtained from 67 cycles stimulated by human menopausal gonadotropin. Cleavage to the 2-, 3-, and 4-cell stage was observed. Four polyspermic oocytes were identified among 85 oocytes obtained from 47 cycles stimulated by clomiphene citrate. Cleavage was not observed. Careful dispersion of cumulus cells at 15 to 18 hours and examination of the oocytes for polyspermy is essential, because the condition may not be apparent at 40 hours from insemination, when normal-appearing cleavage stages may be observed.