Based on my hormone trends (luteinizing hormone surge, estrone‑3‑glucuronide and pregnanediol‑glucuronide levels) and cramps on cycle day 15, did I ovulate, on which cycle day did ovulation occur, when should I start progesterone therapy for luteal phase insufficiency, and how long does the released oocyte remain viable for fertilization (e.g., through late cycle day 15 or day 16)?

Ovulation Timing and Progesterone Therapy Guidance

Did Ovulation Occur and When?

Yes, you ovulated on cycle day 13 or early cycle day 14, confirmed by your LH peak of 45 on CD13 and the subsequent hormone pattern changes. 1, 2

Evidence Supporting Ovulation Timing:

• Your LH surge peaked at 45 IU/L on CD13, which is the primary trigger for ovulation and confirms ovulation occurred within 24-36 hours of this peak 1, 2
• E1G peaked at 288.2 on CD13, indicating maximal follicular maturation immediately before ovulation 3, 4
• The subsequent decline in E1G (from 288.2 on CD13 to 197.8 on CD14 to 133.7 on CD15) is the expected post-ovulatory pattern 3, 4
• Your PDG rose from 3.1 on CD13 to 4.7 on CD14, indicating corpus luteum formation after follicle rupture 1, 5

Critical concern: Your PDG dropped to 2.1 on CD15, which is below the baseline of 3.2 from CD5 and signals inadequate corpus luteum function. 1

Timing of Progesterone Supplementation

You started progesterone therapy at the correct time (CD15 afternoon), as luteal insufficiency was evident from the PDG decline to 2.1. 1

Rationale for Timing:

• PDG levels should rise progressively after ovulation, but yours declined from 4.7 on CD14 to 2.1 on CD15 1, 6
• A PDG decline within two days after the LH surge indicates inadequate corpus luteum activity and warrants immediate luteal phase support 1
• Mid-luteal progesterone should be ≥5 ng/mL (or equivalent PDG concentration); values below this threshold denote luteal insufficiency requiring supplementation 1, 2
• The American College of Obstetricians and Gynecologists states that progesterone concentrations <6 nmol/L (approximately <2 ng/mL) indicate inadequate luteal function 1

Egg Viability Window

The egg remains viable for approximately 12-24 hours after ovulation, meaning it was likely viable through early CD14 but not through late CD15 or CD16. 7, 8

Fertility Window Details:

• Ovulation occurred on CD13 or early CD14 based on your LH peak 1, 2
• The oocyte is fertilizable for 12-24 hours post-ovulation 7
• Your intercourse on CD15 occurred approximately 24-48 hours after ovulation, which is at the outer limit or beyond the egg's viable window 7, 8
• The fertile window is the 5 days leading up to ovulation plus the day of ovulation itself; days after ovulation have minimal conception probability 8

Impact of Progesterone on Fertilization

Progesterone supplementation started on CD15 does not prevent fertilization if it occurred before administration, but the egg was likely no longer viable by that time. 5

Key Points:

• Exogenous progesterone does not block sperm from reaching or fertilizing an egg that is still viable 5
• However, progesterone supplementation may complicate hormone interpretation, as it maintains artificially elevated progesterone levels even as the corpus luteum regresses 1
• Your CD15 cramps likely represent post-ovulatory changes or corpus luteum activity, not active ovulation 6

Clinical Interpretation Summary

Your hormone pattern shows clear ovulation on CD13 with immediate luteal insufficiency, making progesterone supplementation appropriate but intercourse timing suboptimal for conception this cycle. 1, 6

Important Caveats:

• The most fertile days were CD11-13 (before and during the LH surge), not CD15 8
• For future cycles, aim for intercourse during the rising E1G phase (CD11-13) rather than after ovulation 8, 4
• Continue progesterone supplementation through at least 7 days post-ovulation (approximately CD20-21) to support potential implantation 1, 6
• Consider beta-hCG testing if menses does not occur by expected date to definitively confirm or rule out pregnancy 1