When should a healthy couple trying to conceive have intercourse relative to ovulation to maximize pregnancy chances?

Optimal Timing of Intercourse for Conception

For couples with regular menstrual cycles (26-32 days), have intercourse every 1-2 days starting soon after menstruation ends, or use urinary ovulation predictor kits to detect the LH surge and then have intercourse when detected and continue for 2-3 days. 1

Understanding Your Fertile Window

The fertile window is approximately 6 days long, ending on the day of ovulation. 2 The highest probability of pregnancy occurs on the day immediately before ovulation, with conception chances dropping to near zero after ovulation has occurred. 2

For Women with Regular Cycles (26-32 days)

• The most fertile days are cycle days 8-19 of your menstrual cycle. 1, 3
• Ovulation typically occurs during days 9-20 of an average 28-day cycle. 1
• However, even among women with regular cycles, the timing of the 6-day fertile window varies considerably from cycle to cycle. 1

For Women with Shorter Cycles (<26 days)

• Ovulation occurs earlier in shorter cycles. 1
• For a 25-day cycle, the fertile period typically falls between days 6-11, with ovulation around days 11-12. 1

Two Evidence-Based Approaches

Approach 1: Frequent Intercourse Method (No Tracking Required)

Have vaginal intercourse every 1-2 days beginning soon after your menstrual period ends. 1 This approach ensures coverage of the fertile window without requiring ovulation prediction and is particularly useful if you prefer not to track ovulation. 1

Approach 2: Ovulation Prediction Method (More Targeted)

Use urinary ovulation predictor kits starting several days before expected ovulation, then have intercourse when the LH surge is detected and continue for 2-3 days. 1, 3

• Urinary ovulation detection kits detect the luteinizing hormone (LH) surge that precedes ovulation by 24-36 hours. 1
• This method probably increases the chance of live birth compared to intercourse without ovulation prediction (from 16% to 16-28% per cycle). 4
• Urinary ovulation tests probably also increase pregnancy rates overall. 4

Why Ovulation Prediction Matters

Most women significantly misjudge their ovulation day—only 12.7% correctly estimate it, with errors ranging from 10 days early to 27 days late. 5 The most common assumption is that ovulation occurs on day 14, but only 55% of women's estimated ovulation days actually fall within their true fertile window. 5

Recognizing Your Fertile Window

During the 6-day fertile window, you may notice slippery, stretchy cervical mucus—this is a reliable sign of fertility. 1, 3 Methods that prospectively identify the fertile window (like monitoring cervical mucus or using ovulation predictor kits) are more effective than calendar calculations or basal body temperature for timing intercourse. 6

Important Caveats and Pitfalls

For Women with Irregular Cycles

If your cycles are irregular (<26 or >32 days), ovulation prediction becomes even more critical because the fertile window shifts unpredictably. 1 Calendar-based methods are unreliable in this situation—use urinary ovulation predictor kits instead.

Factors That May Reduce Fertility

• Avoid smoking, alcohol consumption, and recreational drug use, as these may reduce fertility. 1
• Avoid most commercially available vaginal lubricants, which might reduce fertility. 1
• Fertility rates are lower among women who are very thin or obese, and those consuming high levels of caffeine (>5 cups per day). 1

When to Seek Further Evaluation

If you have been having fertility-oriented intercourse (timed appropriately) for 6 months without conception, consider investigating female infertility factors, as fertility-oriented intercourse has a major impact in reducing time to pregnancy. 7