40w LaterGuide

It may sound obvious, but the best way to increase your chances of pregnancy is to have intercourse during the fertile window—the time when pregnancy is most likely to occur.

The challenge is knowing exactly when this fertile window occurs and how often intercourse should take place during that period.

According to the most widely accepted theory, if the day of ovulation is known, the fertile window is considered to be the six-day period from five days before ovulation through the day of ovulation itself.

Why start 5 days before ovulation?
For pregnancy to occur, sperm and egg must meet and fertilization must take place. Sperm can survive in the female reproductive tract for up to five days after intercourse. Therefore, sperm that entered the uterus five days before ovulation may still be alive and capable of fertilizing the egg once ovulation occurs.

Why only until the day of ovulation?
Once released, an egg can survive for only about 12–24 hours. After that, it can no longer be fertilized. For this reason, the fertile window is generally considered to end on the day of ovulation.

Of course, pregnancy is not impossible outside of this window. However, one study found that the chance of conception from intercourse occurring outside the fertile window was less than 1%.

Should you have intercourse every day during those 6 days?
Not necessarily. Even within the fertile window, the days with the highest chance of conception are from two days before ovulation through the day of ovulation. It is especially important not to miss this period.

The graph above shows the probability of conception per intercourse among healthy women aged 26–35 years who had intercourse during their fertile window. Naturally, these rates may be lower in women with fertility-related conditions or at older ages.

Having intercourse multiple times during the fertile window generally increases the likelihood of conception. However, daily intercourse may be physically demanding for some couples. In addition, sperm count and quality temporarily decrease after ejaculation and may take approximately 2–3 days to recover.

Considering sperm quality, having intercourse every other day is generally sufficient. However, if both partners are comfortable and wish to maximize their chances, daily intercourse during the fertile window is also acceptable.

Summary
1. Timing intercourse around ovulation is important for increasing the chance of pregnancy.
2. The fertile window is generally considered to be from 5 days before ovulation through the day of ovulation.
3. Having intercourse multiple times (at least twice) during the fertile window is recommended. Intercourse every other day is usually sufficient, but having intercourse at least once between 2 days before ovulation and the day of ovulation may further improve the chance of conception.

Source: New England Journal of Medicine (1995), Timing of Sexual Intercourse in Relation to Ovulation

Medical Review : Dr. Eung-Seok Lee, Infertility Specialist in Obstetrics and Gynecology