Timing of Ovulation and Conception Probability
Based on your hormone patterns, you most likely ovulated in the late evening of CD14 or early morning of CD15, and your intercourse timing on CD10, 12,13,14, and 15 provides excellent conception probability—you did not miss your chance.
Understanding Your LH Surge Pattern
Your LH surge demonstrates the classic pattern that predicts ovulation timing:
- CD13 evening: LH rose to 26.7, marking the beginning of your LH surge 1, 2
- CD14 9:30am: LH peaked at 45, representing your maximum surge 3
- CD14 7:30pm: LH declining to 22, indicating the surge was resolving 3
- CD15 FMU: LH at 18.6, confirming post-surge decline 3
Ovulation occurs 28-36 hours after the beginning of the LH rise, or approximately 10±5 hours from the LH peak 1, 2. Using your CD13 evening surge onset (6:15pm), ovulation would be expected between CD14 10:15pm and CD15 6:15am. The cramping you experienced at 2am on CD15 likely represented ovulation itself 1.
Your Estrogen and Progesterone Patterns Confirm This Timing
Your hormone progression supports late CD14/early CD15 ovulation:
- Rising E1g through CD15 (176.2→215.1→258.6): The continued estrogen rise through CD15 morning is consistent with pre-ovulatory follicle maturation 1
- Stable low Pdg on CD13-14 (1.6→1.5): Appropriate pre-ovulatory baseline 2
- Pdg drop to 1.1 on CD15: This transient dip before the post-ovulatory rise is characteristic of the immediate peri-ovulatory period 2
The thick, stretchy cervical mucus on CD13 and egg-white cervical mucus on CD14 further confirm optimal fertility during this window 1.
Your Intercourse Timing Was Excellent
Sperm can survive in the female reproductive tract for up to 5 days, with optimal survival occurring when intercourse happens before ovulation 4. Your pattern provides multiple opportunities for conception:
- CD10 evening: 4-5 days before ovulation—within the fertile window 4
- CD12 evening: 2-3 days before ovulation—excellent timing 4
- CD13 evening: 1-2 days before ovulation—optimal timing 4
- CD14 evening: Day of ovulation—still excellent 4
- CD15 12:30pm: Likely within hours after ovulation—acceptable timing 4
Research demonstrates that intercourse on the day before ovulation and two days before ovulation provides the highest conception probability 4. You achieved intercourse on both of these optimal days (CD13 and CD14).
Should You Have Intercourse on CD16?
Additional intercourse on CD16 is unlikely to increase conception probability but causes no harm 4. Once ovulation has occurred (which your CD15 morning hormones and symptoms confirm), the egg remains viable for only 12-24 hours 1. Given that ovulation likely occurred in the early hours of CD15, the egg would no longer be fertilizable by CD16 evening.
However, if you are uncertain about exact ovulation timing, intercourse on CD16 provides additional insurance without any downside 4.
Important Caveats About LH Surge Variability
Individual LH surges are extremely variable in configuration, amplitude, and duration 3. Your surge pattern with multiple measurements showing:
- A clear rise from baseline (12.3→26.7)
- A distinct peak (45)
- Appropriate decline post-peak
This represents a textbook pattern, but some women have multi-peaked surges or prolonged surges lasting >3 days 3. The variability in LH patterns means that the onset of the LH rise is more accurate than the LH peak for determining ovulation timing 5.
Conception Probability Assessment
You did not miss your chance. With intercourse on CD12, CD13, and CD14—all occurring before ovulation—you achieved optimal timing for conception 4. The intercourse on CD10 and CD15 provides additional coverage of the fertile window 4.
During a typical 28-day cycle, ovulation generally occurs during days 9-20, with significant individual variation 4. Your ovulation on CD14-15 falls within the expected range and your intercourse pattern covered the critical pre-ovulatory period when conception probability is highest 4.