Most sexually active women spend the majority of their menstrual cycles trying not to get pregnant. But when it finally comes time to start trying for a baby, it can be hard to know how to optimize your chances of success. When should you have sex? How often? Which days are you most fertile?

While this can certainly vary, the majority of women’s menstrual cycles are 28 days long. As a quick review, the first day of your cycle is the first day of your period. Ovulation, or when an egg is released from an ovary, usually occurs on day 14 of the cycle. Some variation in this timing is normal.

You can think of a “fertile window,” as the six days before ovulation occurs (with the last day being the day of ovulation). This might seem counterintuitive — shouldn’t you be the most fertile after you ovulate? In reality, your egg needs to be released from an ovary, be caught by the fallopian tube, and then travel down the fallopian tube, where it will finally meet the sperm. This takes time.

Since an egg is only able to be fertilized for about 12-24 hours, and it spends a lot of that time in transit, it is ideal to have the sperm ready and waiting in the fallopian tube by the time it arrives. This is why that fertile window is before ovulation—if you have sex the day before you ovulate, it gives the sperm time to get to where they need to be to meet the egg when it is actually released during ovulation. It’s a good thing sperm can last as long as 48-72 hours and patiently wait for the egg to arrive!

If you are trying to get pregnant, most physicians will advise you to have sex in the three days leading up to and including ovulation (and you can track your ovulation by following certain symptoms or using over-the-counter ovulation predictor kits, which are not perfect but usually pretty reliable). While optimal intercourse frequency hasn’t been determined, having sex every one to two days is considered best. There is no science behind recommending sex daily versus every other day, and couples should do whatever is personally comfortable for them.

And remember — every woman’s fertile window can vary based on her cycles and her health. If you are having trouble figuring out your cycles or are frustrated with the conception process, be sure to talk to your doctor.


  • You are actually most fertile in the days leading up to ovulation.
  • Ovulation usually occurs on day 14 of the menstrual cycle, but this can vary.
  • While optimal intercourse frequency hasn’t been determined, having sex every 1-2 days is considered best.

Written Jennifer Lincoln, MD, IBCLC, Board Certified OB/GYN

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