Is there a limit for the number of in vitro fertilization cycles for an individual patient?

To examine whether and when conception may be achieved in multiple repeated in vitro fertilization cycles, we surveyed the outcome of 2760 consecutive cycles in our unit. The pregnancy rate statistically significantly decreased after the third cycle attempt, but no statistically significant decrease was observed between cycles 4 and 20; an acceptable clinical pregnancy rate/cycle of 15% was achieved between cycles 7 and 20.