Timing of Implantation After Ovulation
Implantation typically occurs 6-12 days after ovulation, with the majority of successful pregnancies implanting between days 8-10. 1, 2, 3
Precise Timeline Based on High-Quality Research
The most definitive data comes from a prospective study of 221 women attempting conception with daily urine monitoring, which demonstrated:
- Implantation window: 6-12 days post-ovulation 3
- Most common timing: Days 8-10 post-ovulation (84% of successful pregnancies) 3
- Day 8 or 9: Optimal implantation timing with lowest pregnancy loss risk 3
Clinical Significance of Implantation Timing
Earlier implantation is associated with better pregnancy outcomes:
- Implantation by day 9: 13% early pregnancy loss rate 3
- Implantation on day 10: 26% early pregnancy loss rate 3
- Implantation on day 11: 52% early pregnancy loss rate 3
- Implantation after day 11: 82% early pregnancy loss rate 3
This demonstrates that the risk of early pregnancy loss increases dramatically with each day of delayed implantation beyond day 9 3.
Practical Implications for Pregnancy Detection
hCG production begins only after implantation occurs, which explains why pregnancy tests cannot detect pregnancy immediately after conception 1, 2:
- Most urine pregnancy tests detect hCG at 20-25 mIU/mL sensitivity 2
- Tests typically become positive 3-4 days after implantation 1, 2
- By 3 weeks after unprotected intercourse, 97-98% of pregnancies are detectable on standard urine tests 1, 2
Optimal Conception Window
For context, conception itself occurs during a 6-day fertile window ending on the day of ovulation 4:
- Intercourse 5 days before ovulation: 10% conception probability 4
- Intercourse on day of ovulation: 33% conception probability 4
The ideal implantation window of 6-10 days after the LH surge is critical for pregnancy success 5.