The headline numbers

The most commonly cited IVF statistic is the live birth rate per cycle, broken down by age of the person providing eggs. According to SART data from 2021, the national averages for live birth per intended egg retrieval are:

  • Under 35: 54.4%
  • 35 to 37: 41.1%
  • 38 to 40: 26.7%
  • 41 to 42: 13.8%
  • Over 42: 4.3%

These numbers represent the cumulative chance of a live birth from all embryos created in a single retrieval, including any frozen embryo transfers that follow. They are not per-transfer rates.

Why clinic-reported rates vary so much

You may notice that one clinic reports a 65% success rate while another reports 45%, and wonder which is "better." The gap usually reflects patient selection, not skill. A clinic that accepts only straightforward cases with good prognosis will report higher rates than one that regularly takes patients other clinics have turned away.

Other factors that affect reported rates include:

  • Single vs. multiple embryo transfer: Transferring two embryos increases the per-transfer pregnancy rate but also increases twins, preterm birth, and NICU stays. Clinics that prioritize single embryo transfer (eSET) may report slightly lower pregnancy rates but better outcomes per baby.
  • Fresh vs. frozen transfer: Frozen embryo transfers (FET) have caught up to and sometimes surpass fresh transfer rates, partly because the uterine environment is more controlled. Clinics that freeze all may report differently than those doing mostly fresh transfers.
  • PGT-A testing: Genetically tested embryos have per-transfer rates of 60% to 65% regardless of age at retrieval, but fewer embryos survive testing. The per-retrieval rate factors in that attrition.

What actually predicts your outcome

Your individual prognosis depends on a handful of measurable factors:

  • Age: The single strongest predictor. Egg quality declines with age, and no protocol can reverse that decline.
  • AMH (anti-Mullerian hormone): Predicts how many eggs you are likely to retrieve. Higher AMH generally means more eggs, more embryos, and more chances per retrieval.
  • Antral follicle count (AFC): The number of small follicles visible on baseline ultrasound. Correlates with AMH and retrieval yield.
  • Previous response: If this is not your first cycle, your response to stimulation in prior cycles is one of the best predictors of future response.
  • Sperm quality: Severe male factor (very low count, motility, or morphology) can affect fertilization rates even with ICSI.
  • Uterine factors: Polyps, fibroids, or adenomyosis can reduce implantation rates. These are often treatable before transfer.

How to use SART data

The SART website (sart.org) lets you look up individual clinic results. When comparing clinics, look at:

  • Live birth rate per intended egg retrieval (the most honest metric)
  • Number of cycles reported (larger sample = more reliable data)
  • Percentage of eSET (single embryo transfer, a marker of responsible practice)
  • Cancellation rate (a very low rate might mean the clinic cherry-picks easy cases)

Avoid comparing pregnancy rates (which include biochemical pregnancies and miscarriages) or per-transfer rates (which exclude cancelled transfers and failed fertilizations).

The emotional math

A 40% success rate means a 60% chance it will not work on the first try. That is a coin flip with slightly worse odds. It also means that after two cycles, your cumulative chance is roughly 64%. After three, roughly 78%. IVF is often a multi-cycle commitment, not a one-shot procedure.

Processing these numbers is its own emotional work. A percentage cannot account for how it feels to be on either side of it. If you are finding the data overwhelming, our guide on IVF and mental health covers strategies for the emotional weight of treatment.

Next steps

Search for fertility specialists in the Baaby provider directory, or explore the rest of our IVF guides for information on medications, costs, and the two-week wait.