Bottom line up front: Age and embryo quality are the two largest drivers of IVF success — clinic protocol quality and lab standards matter meaningfully too, but don't override the biological factors as much as marketing sometimes suggests.
The genuinely significant factors
- Age (specifically egg age) — the single largest driver of success, covered in depth in our age-specific success rate article
- Embryo quality — genetically and morphologically normal embryos implant more reliably
- Uterine receptivity — the endometrial lining's readiness for implantation
- Clinic lab standards — embryology lab quality genuinely affects embryo development rates
Factors with a more modest, debated impact
Various "add-on" treatments marketed to improve success carry more mixed or limited evidence — covered specifically in our dedicated add-ons evidence review.
Why understanding this hierarchy matters
Focusing your attention and resources on the factors with genuine evidence behind them — verified clinic quality, appropriate protocol for your situation — matters more than chasing every available add-on.
See colombianivf.com for a proper evaluation of your specific success-factor profile.
The Takeaway
Prioritize the factors with the strongest evidence behind them — age-appropriate expectations, embryo quality, and verified clinic standards — over marketed add-ons with weaker evidence.