When should we have sex after detecting the Luteinizing Hormone (LH) surge to maximize conception chances?

Timing Intercourse After LH Surge for Maximum Conception Chances

For optimal conception chances, have intercourse within 24-48 hours after detecting the LH surge. 1

Understanding the Fertile Window and Ovulation Timing

The timing of intercourse relative to ovulation is critical for conception success. Here's what happens after an LH surge:

• Ovulation typically occurs 24-36 hours after the initial LH rise, or approximately 8-20 hours after the LH peak 1
• The fertile window extends from 3 days before to 1 day after ovulation 1
• Peak fertility occurs on the day of LH surge detection and the following day 1

Evidence-Based Recommendations for Timing Intercourse

For Natural Conception:

• Have intercourse within 24-48 hours after detecting the LH surge 1
• Continue intercourse for 1-2 days after the LH surge to maximize chances
• The quality of cervical mucus is strongly associated with conception probability - intercourse on days with optimal mucus quality (clear, slippery, stretchy) increases conception chances regardless of exact timing relative to ovulation 2

For Assisted Conception (IUI):

• IUI in natural cycles should be performed 1 day after LH rise 3, 1
• If using hCG trigger, IUI can be performed between 24-40 hours after injection without compromising pregnancy rates 3, 1

Common Pitfalls to Avoid

1. Waiting too long after LH surge: Delaying intercourse beyond 48 hours after the LH surge may miss the optimal fertilization window as the egg's viability decreases rapidly after ovulation

2. Focusing only on ovulation day: The fertile window extends before ovulation, and sperm can survive for several days in the female reproductive tract

3. Creating unnecessary stress: The stress of strictly timed intercourse can potentially hinder normal reproductive functioning 4

4. Relying solely on calendar methods: These are less accurate than LH detection kits for predicting ovulation

5. Infrequent intercourse: Having intercourse at least a couple of times per week throughout the cycle helps ensure coverage of the fertile window 4

Recent evidence from a Cochrane review shows that timed intercourse using urine ovulation tests probably improves live birth and pregnancy rates in women under 40 who have been trying to conceive for less than 12 months, compared to intercourse without ovulation prediction (RR 1.36,95% CI 1.02 to 1.81) 5.

For couples using ovulation prediction methods, following the 24-48 hour window after LH surge detection provides the best opportunity for conception while minimizing the stress associated with overly rigid timing requirements.