Luteal Phase Hormone Levels After Letrozole Ovulation Induction
Your E1G level of 100 and PDG of 20 at 7 days post-ovulation indicate successful ovulation with adequate luteal support, though the E1G is somewhat elevated compared to typical letrozole cycles.
Understanding Your Hormone Levels
Progesterone (PDG) Assessment
- Your PDG of 20 confirms robust ovulation occurred 1. The American College of Obstetricians and Gynecologists confirms ovulation with PDG ≥5 µg/ml in urine (or progesterone ≥5 ng/ml in serum) at 7 days post-ovulation 1.
- Your level of 20 is well above this threshold, indicating strong corpus luteum function 1.
- Letrozole-associated cycles can produce progesterone levels comparable to standard ovulation induction, with studies showing mid-luteal progesterone levels ranging from 8.6-26.7 ng/ml 2, 3.
- The combination of letrozole with progesterone supplementation you're receiving may contribute to these adequate levels 4.
Estrone (E1G) Considerations
- Your E1G of 100 is elevated but not unexpected with letrozole ovulation induction 1. The American Society for Reproductive Medicine notes that letrozole affects hormone patterns including rising E1G levels during follicle development 1.
- While letrozole typically results in lower estrogen levels than standard ovulation induction, individual variation exists 1.
- Importantly, letrozole supplementation can paradoxically increase progesterone levels in the late follicular and luteal phases 5, 6. Studies show 59% of letrozole-treated patients had mid-luteal progesterone >30 ng/ml versus 31% in controls 5.
Clinical Implications
Fertility Window Optimization
- Your timing was appropriate 1. The CDC indicates sperm can survive 3-5 days in fertile cervical mucus, so intercourse from CD11-CD15 would have been within the fertile window given your CD15 ovulation 1.
- Ovulation confirmation on CD15 with progesterone supplementation started that night follows standard protocols 1.
Letrozole-Specific Effects
- Letrozole at 7.5 mg (CD3-7) is a higher dose than standard 7. The FDA-approved dose for ovulation induction is typically 2.5-5 mg daily 7.
- Higher letrozole doses may explain your elevated E1G, as letrozole increases LH by 38% in the follicular phase and testosterone by 79%, which can be aromatized to estrogens 5.
- Letrozole reduces estradiol by approximately 68% on trigger day but does not eliminate all estrogen production 5, 2.
Progesterone Elevation Pattern
- Studies demonstrate that letrozole supplementation increases the risk of elevated progesterone levels 6. Research shows 24.81-25.45% of letrozole-supplemented patients have progesterone >1.5 ng/ml on trigger day versus 7.52-12.70% in controls 6.
- For every retrieved oocyte, progesterone increases by 0.05 ng/ml in letrozole cycles versus 0.02 ng/ml in standard cycles 6.
- Your progesterone supplementation starting on ovulation night adds to endogenous corpus luteum production, potentially explaining robust luteal phase support 4.
Common Pitfalls to Avoid
- Do not assume low estrogen throughout the cycle with letrozole 5, 2. While estradiol is suppressed during stimulation, post-ovulatory estrogen metabolism can vary 1.
- Timing of progesterone measurement is critical 5. Your 7-day post-LH surge timing is appropriate, though diurnal variation exists 5.
- High-dose letrozole (7.5 mg) may have different hormonal effects than standard 2.5-5 mg doses 7, 4. Consider discussing dose optimization with your provider for future cycles.
Monitoring Recommendations
- Continue progesterone supplementation as prescribed 4. The combination of endogenous and exogenous progesterone provides optimal luteal support 4.
- If pregnancy does not occur this cycle, consider whether the 7.5 mg letrozole dose is necessary or if 5 mg would provide adequate ovulation with potentially more favorable hormone profiles 7, 4.
- Your hormone levels suggest successful ovulation with adequate luteal support, which are the primary goals of this treatment protocol 1, 4.