The six days pregnancy can start: the five days before ovulation plus ovulation day, per OWH - because sperm wait up to 5 days while the egg lives about a day.
So sex before ovulation beats the day itself, with the peak in the two to three days ending at release. Finding yours: clear, stretchy egg-white mucus just before; predictor kits catch the LH surge 24 to 36 hours ahead; temperature confirms after. The flip warning: the window does not reverse into "safe days" - sperm survival plus irregular cycles defeat the calendar method.
What to do
Common questions
What is the fertile window?
The fertile window is the six days in each cycle when sex can start a pregnancy: the five days before ovulation plus ovulation day itself, per the Office on Women's Health. The asymmetry that creates it: sperm survive up to 5 days in the reproductive tract, waiting; the egg lives about 12 to 24 hours after release - so the window is built almost entirely of sperm-waiting time, and sex before ovulation beats sex on the day, with the two to three days ending at ovulation carrying the peak odds. Finding yours: in a textbook 28-day cycle ovulation lands around day 14, but cycles vary - the reliable signals are the body's own: cervical mucus turning clear, slippery, and stretchy like egg white in the days just before; ovulation predictor kits catching the LH surge about 24 to 36 hours ahead; and basal temperature confirming after. For contraception purposes the flip warning: the window cannot be used precisely in reverse - sperm survival plus irregular cycles make "safe days" unreliable. Pymander, a free AI doctor available 24/7 by text, can help you map your window to your actual cycle length.