Making Sense of IVF Success Rates

Turning to fertility treatment to build your family can feel daunting. Are all infertility clinics basically the same when it comes to in vitro fertilization (IVF)? If not, how do you find out about their differences?

Many empowered health consumers turn to regularly published reports by two collaborating organizations: the Society for Assisted Reproductive Technology (SART) and the U.S. Department of Health and Human Services Centers for Disease Control and Prevention. These two groups are responsible for compiling and reporting statistics from American fertility clinics on the outcome of assisted reproductive technology (ART), specifically IVF.

The latest statistics published by SART are now out and describe a steadily improving rate of treatment success by way of the numbers for 2005.

Defining Success

"Success" can have various meanings in the world of medicine. Just as it's important to use a critical eye when reading IVF research, the consumers of healthcare services should understand what the numbers really mean when evaluating whether or not to use a given practice.

The SART website plainly states that the best measure of success is what's known as the "take home baby rate", which can be different from a clinic's pregnancy rate. After all, the goal of fertility treatment is not just to get pregnant but to have a child.

Who Must Report: The Law

A law passed by the U.S. Congress in 1992 mandates that all clinics performing IVF in the United States must report their success rate data to the CDC each year. The law is called the Fertility Clinic Success Rate and Certification Act of 1992 [FCSRCA], Section 2 [a] of P.L.102-493 [42 U.S.C. 263 (a) -1] and is fully accessible on the Internet. The CDC is thereby charged by law to account for all known fertility practices engaged in the use of IVF. Any practices that fail to report their data as required are listed in the CDC reports under the category, "nonreporters."

SART, on the other hand, is a voluntary membership organization and has its own rules about which of its members must report and when. The member practices of SART represent over 85 percent of all U.S. IVF clinics.

How Data is Gathered: The Process

The actual reporting process starts the moment a treatment cycle is initiated. Whether or not the cycle is completed or cancelled, information on the following is turned in by way of a Web-based system (National ART Surveillance System, or NASS) to a statistical analysis company called Westat:

  • date each treatment cycle begins
  • type of treatment used (IVF with or without ICSI, GIFT, or ZIFT)
  • some medical history specifics such as patient's age and diagnosis
  • number of embryos transferred
  • whether donor egg or frozen embryos were used
  • the outcome, whether pregnancy, live birth, singleton, or multiples

Because the outcome of fertility treatment can take the length of a normal pregnancy (40 weeks) to be known, there's a built-in time delay from date of initiated treatment to being able to report the outcome. This fact and the additional steps taken to double-check the accuracy of the process results in significant lag time; hence, the most recent CDC ART report is on statistics from 2004, published in 2006.

SART's reporting procedures are newly streamlined, producing usable statistics in a matter of months rather than years. As of this writing, the most recently published SART report is based on data from the year 2005, and was published in January 2007.

SART reports have the additional advantage of providing data about women patients who are 43 - 44 years old. CDC data goes up to age 42. Also, the SART website includes a feature that allows users to look at outcomes of treatment for various diagnoses. The CDC reports show only the differing percentages of patients with the diagnoses, without exploring the treatment results for each. Given the impact of diagnosis on both treatment plan and its outcome, most patients will find related statistics to be quite pertinent.

Reading Points to Keep in Mind

*While the sources of the eggs used in each treatment cycle are documented (that is, donor eggs or patients' own), the source of sperm -- whether provided by anonymous donor or partner -- is not.

*Some large practices use more than one laboratory. Consumers should evaluate not only the clinic, but compare the different labs used. Patients can specify their preference of lab.

*When more than one practice is involved in any treatment cycle, SART has established rules on which practice is to report that cycle's data.

*Practices with more than one office report as one practice.

*When fewer than 20 cycles are documented, the data is displayed as an exact fraction rather than a percentage. For example, if a clinic reports 37 IVF cycles in women under age 35 and 18 cycles for age group 35 - 37, numbers for the under 35 group would be displayed as percentages (example: 44%) whereas numbers for the older women would be displayed as fractions (example: 4/18).

*Occasionally, practices will put their latest statistics on a website with the primary intention of getting the numbers out there and available to prospective patients before the reporting process can be completed by either SART or CDC. Since there is no independent verification of the success rates reported on a clinic's website, consumers should look carefully at the actual SART and CDC reports before making any decision.

*You will find the following disclaimer on most practice websites that display their own statistics: A comparison of clinic success rates may not be meaningful because patient medical characteristics and treatment approaches may vary from clinic to clinic.
This statement does not invalidate the usefulness of success rate reporting. Rather, it's a reminder to consumers to take their own diagnosis and possible treatment needs into account when looking at the numbers. For example, age is an important variable, as it impacts fertility without any other causal factors. Similarly, the overall success percentages of IVF with donor egg versus a patient using her own eggs are so pronounced that consumers who are evaluating clinics should take care to compare only specific treatments and age groups.

Many patients utilize both the SART and CDC reports for comparing and contrasting clinics to help them choose a fertility practitioner. Such comparisons take time to fully understand the meaning of the different types of numbers available. Start by familiarizing yourself with the reports' appearances. Take a look at the national averages (called "national summary") for all SART member clinics and at CDC. You can then select reports from individual clinics and compare their numbers against both the national average and other clinics' reports.

For more information on making sense of the numbers, start with the CDC's 2004 ART Report: Introduction to Fertility Clinic Tables .

To view the latest SART statistics, visit their website.

While all IntegraMed clinics can give you details on their practice-specific statistics, you'll find more on how to make sense of IVF success rates at several of their websites:

The Center for Reproductive Medicine in Orlando

Colorado Center for Reproductive Medicine

Fertility Centers of Illinois

Houston IVF

Reproductive Medicine Associates of New Jersey

Reproductive Science Center of the San Francisco Bay Area

Seattle Reproductive Medicine

Shady Grove Fertility

Southeastern Fertility Center