How many times can it take for a woman to get pregnant? Obviously any woman can get pregnant at anytime if their fertile window and anytime they're partner ejaculates in them. However, in reality, how many times or how long does it take to become pregnant? My partner and I had unprotected sex once and that is the first time we've ever allowed him to cum in me. Have any of you women fell pregnant after just once? We're not necessarily trying but we're not really preventing either. If it happens, it happens.