← Back to IVF Tools
Follicle Count & Assessment Tool
Track follicle development and predict egg retrieval outcomes
Medical Disclaimer
This tool provides estimates based on average IVF outcomes. Actual results vary significantly based on age, egg quality, sperm quality, and laboratory conditions. Your doctor will make trigger timing decisions based on multiple factors including hormone levels, not just follicle sizes. Always follow your clinic's specific guidance.
Enter Follicle Measurements
Add Follicles
No follicles added yet
Total follicles: 0
Understanding Follicle Development
Follicle Size Guidelines:
- 18-22mm: Mature, likely contains mature egg
- 15-17mm: Near mature, may mature by retrieval
- 12-14mm: Intermediate, less likely to be mature
- <12mm: Immature, unlikely to yield mature egg
Typical Growth Rate:
Follicles typically grow 1-2mm per day during stimulation. Growth may accelerate near the end of stimulation.
Trigger Timing:
Usually triggered when 2-3 lead follicles reach 17-18mm, with several others at 14-16mm for optimal mature egg yield.
Medical Sources & References
- • Rosen et al. (2008). "A quantitative assessment of follicle size on oocyte developmental competence." Fertility and Sterility, 90(3), 684-690.
- • Triwitayakorn et al. (2003). "Correlation between human follicular diameter and oocyte outcomes." Journal of Assisted Reproduction, 20(3), 127-133.
- • Ectors et al. (1997). "Relationship of human follicular diameter with oocyte fertilization and development." Human Reproduction, 12(9), 2002-2005.
- • Mehri et al. (2014). "Correlation between follicular diameters and flushing versus no flushing on oocyte maturity." Journal of Human Reproductive Sciences, 7(3), 187-193.
- • ASRM Practice Committee. (2018). "Prevention and treatment of OHSS: a guideline." Fertility and Sterility, 109(5), 870-877.
- • Abbara et al. (2018). "Follicle Size on Day of Trigger Most Likely to Yield a Mature Oocyte." Frontiers in Endocrinology, 9, 193.