The best time to have intercourse for conception is the so-called "fertile window." The fertile window is defined as the days of the menstrual cycle during which intercourse is most likely to result in pregnancy. It lasts for 6 days starting at 5 days before ovulation and ends on the day of ovulation. Your most fertile days are the 1-2 days before ovulation and the day of ovulation. Calculate your Fertility Window HERE.
When is the best time to get pregnant?
Your fertile days are the 4-5 days before ovulation and the day of ovulation, while the most fertile days are the 2 days before ovulation and the day of ovulation.
Increasing amounts of estrogen in the cervical mucus and reproductive tract of a women approaching ovulation generally allows the sperm to live for up to 6 days. Sexual intercourse on the day after established ovulation is unlikely to improve your chances getting pregnant, and the chance of getting pregnant by intercourse after ovulation is nearly zero.
Does timing of intercourse improve your pregnancy chances?
Studies have shown that even in women with regular cycles, "timing" intercourse to get pregnant does not significantly improve your chances of pregnancy. If you wait to have intercourse until the temperature goes up or the ovulation predictor kit (OPK) becomes positive, you are probably not improving your chances because you may have already ovulated. Sex after ovulation is unlikely to get you pregnant.
Every day versus every other day?
Previously, couples trying to conceive (TTC) were told to have sex once every other day during their fertile days. However, recent studies have shown that for the average couple trying to conceive, making love 2-3 times a week, every week, is the best way to ensure that intercourse is ocurring before and during ovulation. You may improve your chances further by by having sex once a day (as long as his sperm are OK) during the fertile 4-5 days prior to and including ovulation day. In those instances where the man does not have enough sperm (oligospermia), the recommendation of once every other day still holds true.
Sex During Fertile Days: % Pregnancy
- Sex every day: 37% Pregnancy
- Sex every other day: 33% Pregnancy
- Sex once a week: 15% Pregnancy
Source: "Timing of Sexual Intercourse in Relation to Ovulation -- Effects on the Probability of Conception, Survival of the Pregnancy, and Sex of the Baby" was published in The New England Journal of Medicine (December 7, 1995 -- Vol. 333, No. 23). Allen J. Wilcox, Clarice R. Weinberg, Donna D. Bair