IVF success factors

Several factors, but they are not equal. The single biggest one is the age of the eggs, because egg quality — and with it the chance an embryo is chromosomally normal — declines with age. That's why IVF success with your own eggs is highest under 35 and falls steadily after the mid-30s. Egg source matters just as much: donor eggs from a young donor largely remove that age effect for the recipient. After that come a cluster of factors a clinic weighs: prior births (generally favorable), prior IVF and how you responded, BMI and general health, and the specific reason for infertility (IVF is often effective for tubal- or male-factor infertility, more challenging with diminished ovarian reserve). And because success is reported per cycle while the odds build across cycles, the number of cycles you're able to do matters too. No single factor decides it — which is exactly why a real estimate has to combine all of them.

Per-cycle success is the chance that one IVF cycle leads to a live birth. Cumulative success is the chance of a birth across several cycles — and it's higher, because each additional cycle is another opportunity. This distinction trips people up constantly: a per-cycle figure can look discouraging on its own, yet many people who don't succeed in the first cycle do in a second or third. It also cuts the other way — cumulative rates assume you keep going, which has real cost, time, and emotional weight, and not everyone can or wants to do multiple cycles. When you read any IVF success number, the first question to ask is whether it's per cycle or cumulative, because they answer different questions. The CDC and SART tools can show cumulative estimates precisely because they model the effect of doing more than one cycle.

Because an honest one can't come from a web page. A real, personalized IVF success percentage is produced by validated statistical models — the CDC IVF Success Estimator and the SART patient predictor — that were built on national ART surveillance data (hundreds of thousands of reported cycles) and that take your specific inputs (age, height and weight, prior pregnancies and births, prior IVF, the reason for infertility, and whether you'd use your own or donor eggs). Reproducing those models, or worse, inventing a number, would be misleading in a decision this consequential. So this tool does the part a page can do honestly: it explains which factors move the odds and in which direction, so you walk into those tools — and into a clinic — knowing how to read what they show. For your actual number, use the CDC IVF Success Estimator or SART predictor together with a fertility clinic, which can also tell you where a model's estimate is less reliable for someone like you.

Largely, yes — and this surprises many people. Because embryo quality is driven mostly by the age of the egg, using eggs from a young donor means the egg-age clock is the donor's, not yours. So donor-egg IVF success is generally favorable and relatively stable across a wide range of recipient ages, rather than falling year by year the way own-egg success does. That's why donor eggs come up so often in counseling for people in their 40s. It isn't a blank check, though: your uterine health, the lining, any medical conditions, BMI, and overall health still matter, pregnancy at older ages carries its own risks that a clinic will discuss, and no path guarantees a birth. Whether donor eggs are right for you is a personal decision to make with a fertility specialist, not something to conclude from a table.

It can, modestly. A BMI well outside the healthy range — at either the low or the high end — is associated with somewhat lower IVF success and with higher risks during stimulation and pregnancy. We're deliberately not putting a number on that, because the effect is smaller than age and varies from person to person, and quoting a false-precise figure would mislead. The practical takeaway is that BMI is one of the inputs the CDC and SART estimators ask for, and it's a factor a clinic may talk through with you — sometimes as something worth addressing before or alongside treatment. It is one lever among several, not a verdict: plenty of people conceive through IVF across a range of body sizes. Your clinic is the right place to understand how it applies to you specifically.

Yes. This tool runs entirely in your browser: your age and the factors you select are used on your own device to show general educational information and are never sent to a server, saved, or shared — close the tab and they're gone. We treat reproductive data as sensitive by default, so nothing here creates a record anywhere. Note that the CDC IVF Success Estimator and SART predictor we point you to are separate, reputable tools with their own privacy terms (the CDC states it does not store what you enter) — but they are not us, so review their notices when you use them. This page is general education based on ASRM, ACOG, CDC, and SART guidance; it is not medical advice, a diagnosis, a fertility test, or a prediction of your personal chances — only a fertility clinic, with those validated tools, can assess those.