What the IVF Age Bands Mean: Under 35, 35-37, 38-40 and Over 40

By Berkcan K., editor · Published 2026-10-22 · Updated 2026-10-23

Every success rate the CDC publishes for patients using their own eggs is split into four age groups: under 35, 35 to 37, 38 to 40, and over 40. The CDC says plainly that its success-rate data are “presented by patient age group” and that chances “may vary according to age”; the bands exist because the patient’s age at the start of the cycle is the single strongest predictor of whether an egg will become a baby. A clinic’s overall rate, averaged across all ages, says more about who walked in the door than about the clinic. This guide shows how large the gaps are, using the CDC’s own national figures for 2022, and what that means when you compare clinics.

How far the national rates fall

Live births per intended egg retrieval, patients using their own eggs, United States, 2022 (CDC national aggregate):

Age band	Live births per intended retrieval	Per actual retrieval	Per transfer	New patients, after all retrievals in the year
Under 35	49.7%	52.6%	49.1%	60.8%
35 to 37	36.3%	39.7%	46.0%	49.9%
38 to 40	23.1%	26.1%	41.2%	35.2%
Over 40	7.7%	9.4%	25.4%	13.4%

Two things stand out. First, the rate per intended retrieval falls by more than six times between the youngest and oldest band. Second, the rate per transfer falls far less, from 49.1% to 25.4%, because so many cycles in the older bands never reach a transfer: they are cancelled, produce no usable eggs, or produce embryos that are banked rather than transferred. That is why a clinic quoting an impressive per-transfer rate for patients over 40 is not telling you the odds of a baby from a started cycle. The intended-retrieval rate is.

The cumulative figure for new patients is the one to read if you are starting treatment: nationally, 60.8% of patients under 35 who began ART in 2022 had a live birth from the retrievals they did that year, against 13.4% of patients over 40.

Why the bands have these edges

The CDC’s cut points follow the biology that fertility medicine has measured for decades: the number of eggs retrievable per cycle and the share of them that are chromosomally normal both decline with age, slowly at first and steeply after the late thirties. The bands are coarse on purpose. Inside “38 to 40” a 38-year-old and a 40-year-old do not share the same odds, and inside “over 40” the range is open-ended, so a clinic whose over-40 patients are mostly 41 will look better than one whose are mostly 44. When you compare two clinics in the same band, you are comparing rates on patients whose ages are similar but not identical.

Why donor-egg rates have no age bands

The CDC defines a donor egg cycle as one “where an embryo is formed from the egg of one woman (the donor)” and transferred to another. Because the egg’s age is the donor’s, not the recipient’s, the recipient’s age tells you little, and the CDC splits donor outcomes by what was transferred instead: fresh embryos from fresh eggs, fresh embryos from frozen eggs, frozen embryos, or donated embryos. Nationally in 2022 those four rates per transfer were 52.0%, 45.2%, 45.1% and 42.2%. If your own-egg prognosis is poor, these are the rows that describe the alternative, and they are the same whatever your age band.

Reading a clinic in its band

Three habits make the age bands useful rather than misleading:

Compare within a band, never across. A clinic with a 40% under-35 rate and a clinic with a 30% 38-to-40 rate have told you nothing about each other. On this site the state and city tables show the under-35 rate for every clinic so that each is read in the same band, listed alphabetically rather than ranked; the clinic pages show all four.
Check the count under the rate. Older bands are smaller. A clinic might have 300 intended retrievals under 35 and 20 over 40, and the CDC prints a fraction rather than a percentage when a cell has fewer than 20 cycles. A fraction like “3 of 12” is a fact about twelve people, not a rate.
Look at the patient mix. Each clinic page lists the diagnoses behind its cycles (diminished ovarian reserve, male factor, unexplained, and so on). A clinic whose cycles are heavy in diminished ovarian reserve is treating a harder group in every band, which lowers its rates without saying anything about its laboratory.

One embryo or two

Age also shapes how many embryos a clinic transfers. ASRM’s patient fact sheet notes that twin and higher-order pregnancies are “more likely with IVF, particularly when more than one embryo is transferred,” that “the more embryos that are transferred into the uterus, the greater the risk,” and advises transferring the minimum number needed. The singleton rows in each band show how often a clinic’s live births were single infants; a singleton rate close to the overall rate means the clinic is reaching its results with single-embryo transfers, which is the safer path for the pregnancy regardless of age.

None of this replaces a consult. Your own ovarian reserve, diagnosis and history move your odds within a band, and only a reproductive endocrinologist can estimate them for you. What the bands do is make the published numbers comparable, and that is the only honest way to read them.