Use of Estradiol Valerate to Postpone Ovarian Stimulation
Estradiol valerate can be used from day 2 of the menstrual cycle to postpone ovarian stimulation for 5-6 days, as it can effectively suppress follicular development during this period. 1, 2
Mechanism and Protocol
- Estradiol valerate works by suppressing follicle-stimulating hormone (FSH), which temporarily prevents follicular development, allowing for scheduling flexibility in ovarian stimulation cycles 1
- The recommended protocol involves administering 4 mg/day of oral estradiol valerate starting from day 2 of the menstrual cycle and continuing for 5-6 days until the desired start date for stimulation 1, 2
- Ovarian stimulation can be initiated the day after discontinuing estradiol valerate, or optimally, 5-6 days after discontinuation to allow for complete clearance of the suppressive effect 2
Efficacy and Outcomes
- Studies have shown that estradiol valerate pretreatment does not negatively impact the number of mature oocytes retrieved compared to cycles without pretreatment 2
- Pregnancy rates with estradiol valerate pretreatment (42.9%) were comparable to or slightly higher than cycles without pretreatment (34.3%), although the difference was not statistically significant 2
- Endometrial thickness and embryo quality were not significantly affected by estradiol valerate pretreatment 2, 3
Practical Considerations
- The duration of estradiol valerate pretreatment can be adjusted based on scheduling needs, with studies showing effective use for periods ranging from 5-12 days 1, 4
- Starting stimulation 5-6 days after discontinuing estradiol valerate may be optimal to avoid any potential suppressive effects on follicular development 2
- Estradiol valerate pretreatment offers a shorter duration of pretreatment (mean 7.8±1.9 days) compared to oral contraceptive pills (mean 14.5±1.7 days), which may be advantageous when time is a consideration 1
Potential Benefits
- Allows for flexible scheduling of ovarian stimulation cycles without compromising outcomes 1, 2
- May improve follicular synchronization, which could theoretically benefit patients with poor ovarian response 4
- Does not appear to negatively impact endometrial receptivity, and may even have beneficial effects on endometrial thickness in some contexts 3
Common Pitfalls and Caveats
- Avoid continuing estradiol valerate during the stimulation phase unless specifically indicated, as this is a different protocol with different outcomes 4
- Monitor for any signs of hyperestrogenism, although side effects are generally minimal at the recommended dosage of 4 mg/day 1, 2
- Consider that while estradiol valerate is effective for short-term postponement of stimulation, longer delays may require different approaches 1