Commonly Asked Questions
About the U.S. ART Clinic Reporting System
Background Information, Data Collection Methods, Content and Design of the Report, and Additional Information About ART in the United States
- How many people in the United States have infertility problems?
- What is assisted reproductive technology (ART)?
- What is an ART cycle?
- How do U.S. ART clinics report data to CDC about their success rates?
- Why is the report of 2008 success rates being published in 2010?
- Which clinics are represented in this report?
- Why doesn’t CDC rank the clinics?
- Does this report include all ART cycles performed by the reporting clinics?
- How are the success rates determined?
- What are my chances of getting pregnant using ART?
- If a woman has had more than one ART treatment cycle, how is the success rate calculated? Alternatively, how many cycles does a woman usually go through before getting pregnant?
- What factors that influence success rates are presented in this report?
- What quality control steps are used to ensure data accuracy?
- How does CDC use the variables/data collected but not reported in the annual Assisted Reproductive Technology Success Rates National Summary and Fertility Clinic Reports?
- How does CDC ensure the confidentiality of the assisted reproductive technology data it collects?
- Why doesn’t the report contain specific medical information about ART?
- Why are summary statistics in the Fertility Clinic tables published by CDC different from summary statistics reported in the SART National Summary?
- Does CDC have any information on the women who donate eggs?
- Are there any medical guidelines for ART performed in the United States?
- Where can I get additional information on U.S. fertility clinics?
- What’s new in the 2008 report?
The latest data on infertility available to the Centers for Disease Control and Prevention (CDC) are from the 2002 National Survey of Family Growth.
- Of the approximately 62 million women of reproductive age in 2002, about 1.2 million, or 2%, had had an infertility-related medical appointment within the previous year and an additional 10% had received infertility services at some time in their lives. (Infertility services include medical tests to diagnose infertility, medical advice and treatments to help a woman become pregnant, and services other than routine prenatal care to prevent miscarriage.)
- Additionally, 7% of married couples in which the woman was of reproductive age (2.1 million couples) reported that they had not used contraception for 12 months and the woman had not become pregnant.
Although various definitions have been used for ART, the definition used in this report is based on the 1992 law that requires CDC to publish this report. According to this definition, ART includes all fertility treatments in which both eggs and sperm are handled. In general, ART procedures involve surgically removing eggs from a woman’s ovaries, combining them with sperm in the laboratory, and returning them to the woman’s body or donating them to another woman. They do NOT include treatments in which only sperm are handled (i.e., intrauterine—or artificial—insemination) or procedures in which a woman takes drugs only to stimulate egg production without the intention of having eggs retrieved.
The types of ART include the following:
- IVF (in vitro fertilization). Involves extracting a woman’s eggs, fertilizing the eggs in the laboratory, and then transferring the resulting embryos into the woman’s uterus through the cervix. For some IVF procedures, fertilization involves a specialized technique known as intracytoplasmic sperm injection (ICSI). In ICSI, a single sperm is injected directly into the woman’s egg.
- GIFT (gamete intrafallopian transfer). Involves using a fiber-optic instrument called a laparoscope to guide the transfer of unfertilized eggs and sperm (gametes) into the woman’s fallopian tubes through small incisions in her abdomen.
- ZIFT (zygote intrafallopian transfer). Involves fertilizing a woman’s eggs in the laboratory and then using a laparoscope to guide the transfer of the fertilized eggs (zygotes) into her fallopian tubes.
In addition, ART often is categorized according to whether the procedure used a woman’s own eggs (nondonor) or eggs from another woman (donor) and according to whether the embryos used were newly fertilized (fresh) or previously fertilized, frozen, and then thawed (frozen). Because an ART procedure includes several steps, it is typically referred to as a cycle of treatment. (See What is an ART cycle? below.)
Because ART consists of several steps over an interval of approximately 2 weeks, an ART procedure is more appropriately considered a cycle of treatment rather than a procedure at a single point in time. The start of an ART cycle is considered to be when a woman begins taking drugs to stimulate egg production or starts ovarian monitoring with the intent of having embryos transferred. (See Figure 6, for a full description of the steps in an ART cycle.) For the purposes of this report, data on all cycles that were started, even those that were discontinued before all steps were undertaken, are submitted to CDC through a Web-based data collection system called the National ART Surveillance System (NASS) and are counted in the clinic’s success rates.
CDC contracts with a statistical survey research organization, Westat, to obtain the data published in the ART success rates report. Westat maintains a list of all ART clinics known to be in operation and tracks clinic reorganizations and closings. This list includes clinics and individual providers that are members of the Society for Assisted Reproductive Technology (SART) as well as clinics and providers that are not SART members. Westat actively follows up reports of ART physicians or clinics not on its list to update the list as needed. Westat maintains NASS, the Web-based data collection system that all ART clinics use. Clinics either electronically enter or import data into NASS for each ART procedure they start in a given reporting year. The data collected include information on the client’s medical history (such as infertility diagnoses), clinical information pertaining to the ART procedure, and information on resulting pregnancies and births.
See below (Why is the report of 2008 success rates being published in 2010?) for a complete description of the reporting process.
Before success rates based on live births can be calculated, every ART pregnancy must be followed up to determine whether a birth occurred. Therefore, the earliest that clinics can report complete annual data is late in the year after ART treatment was initiated (about 9 months past year-end, when all the births have occurred). Accordingly, the results of all the cycles initiated in 2008 were not known until October 2009. After ART outcomes are known, the following occurs before the report is published:
- Clinics enter their data into NASS and verify the data’s accuracy before sending the data to Westat.
- Westat compiles a national data set from the data submitted by individual clinics.
- CDC data analysts conduct comprehensive checks of the numbers reported for every clinic.
- Clinic tables, national figures, and accompanying text for both the printed and Internet versions of the report are compiled and laid out.
- CDC and Westat review the report.
- Necessary changes are incorporated and proofread.
- The report is submitted to the Government Printing Office to begin the printing and production process.
These steps are time-consuming but essential for ensuring that the report provides the public with correct information particularly regarding each clinic’s success rates.
The data in both the national report and the individual fertility clinic tables come from 436 fertility clinics that provided and verified information about the outcomes of the ART cycles started in their clinics in 2008.
Although we believe that almost all clinics that provided ART services in the United States throughout 2008 are represented in this report, data for a few clinics or practitioners are not included because they either were not in operation throughout 2008 or did not report as required. Clinics and practitioners known to have been in operation throughout 2008 that did not report and verify their data are listed in this report as nonreporters, as required by law (see Appendix C, Nonreporting ART Clinics for 2008, by State). We will continue to make every effort to include in future reports all clinics and practitioners providing ART services.
Because the decision to undergo ART treatment is a very personal decision, this report may not contain all of the information that a woman or a couple needs to decide which ART clinic or procedure is best for their treatment. Many factors contribute to the success rate of an ART procedure in particular patients, and a difference in success rates between two ART programs may reflect differences in the groups of patients treated, the types of procedures used, or other factors. More explanations on how to use the success rates and other statistics published in this report are in the Introduction to Fertility Clinic Tables. The report should be used to help people considering an ART procedure find clinics where they can meet personally with ART providers to discuss their specific medical situation and their likelihood of success using ART. Contacting a clinic also may provide additional information that could be helpful in deciding whether or not to use ART. Because ART offers several treatment options for infertility, there are many other factors that may affect the decision. Going through repeated ART cycles requires substantial commitments of time, effort, money, and emotional energy. Therefore, this report may be a helpful starting point for consumers to obtain information and consider their options.
This report includes data for the 148,055 cycles performed in 2008 by the 436 clinics that reported their data as required. A small number of ART cycles are not included in either the national data or the individual fertility clinic tables. These were cycles in which a new treatment procedure was being evaluated. Only 2 ART cycles fell into this category in 2008.
This report presents several measures of success for ART (see Figure 8), including the percentage of ART cycles that result in a pregnancy. The pregnancies reported here were diagnosed using an ultrasound procedure. All live-birth deliveries were reported to the ART physician by either the patient or her obstetric provider. Because this report is geared toward patients, the focus is on the percentage of cycles resulting in live births. Singleton live births are presented as a separate measure of success because they have a much lower risk than multiple-infant births for adverse infant health outcomes, including prematurity, low birth weight, disability, and death. As noted throughout the report, success rates were additionally calculated at various steps of the ART cycle to provide a complete picture of the chances for success as the cycle progresses.
Many women ask this question because they assume that the pregnancy will lead to a live birth. Unfortunately, not all ART procedures that result in a pregnancy lead to the delivery of a live infant. For example, in 2008, 104,673 fresh nondonor ART cycles were started. Of those, 38,631 (37%) led to a pregnancy, but only 31,365 (30%) resulted in a live birth. In other words, 19% of ART pregnancies did not result in a live birth. The percentage of cycles resulting in live births will give a more accurate answer to the question, “If I have an ART procedure, what is my chance that I will have a baby?”
It is important to note that multiple-fetus pregnancies and multiple-infant births are common with ART (see Figure 11). Multiple-infant births are associated with greater risk for adverse health outcomes for both the mother and the infants (see Figures 12 and 13 on preterm deliveries and low birth weight). This report also includes singleton live births as a measure of success because they have a lower risk of adverse health outcomes.
11. If a woman has had more than one ART treatment cycle, how is the success rate calculated? Alternatively, how many cycles does a woman usually go through before getting pregnant?
As required by law, this report presents ART success rates in terms of how many cycles were started each year, rather than in terms of how many women were treated. (A cycle starts when a woman begins taking fertility drugs or having her ovaries monitored for follicle production.) Clinics do not report to CDC the number of women treated at each facility. Because clinics report information only on outcomes for each cycle started, it is not possible to compute the success rates on a “per woman” basis, or the number of cycles that an average woman may undergo before achieving success.
The national report presents a more in-depth picture of ART than can be shown for each individual clinic. Success rates are presented in the context of various patient and treatment characteristics that may influence success. These characteristics include age, infertility diagnosis, history of previous births, previous miscarriages, previous ART cycles, number of embryos transferred, type of ART procedure, use of techniques such as ICSI, and clinic size.
To have their success rates published in this annual report, clinics have to submit their data in time for analysis and the clinics’ medical directors have to verify by signature that the tabulated success rates are accurate. Then, Westat conducts an in-house review and contacts the clinics if corrections are necessary. After the data have been verified, a quality control process called validation begins. This year, 35 of 436 reporting clinics were randomly selected for site visits. Members of the Westat Validation Team visited these clinics and reviewed medical record data for a sample of the clinic’s ART cycles. For each cycle, the validation team abstracted information from the patient’s medical record. The abstracted information was then reviewed on-site and compared with the data submitted for the report. CDC staff members participated as observers in some of the visits. For each clinic, the sample of cycles validated included all cycles that were reported to have multiple-fetus pregnancies and a random sample of up to 50 additional cycles. In almost all cases, data available in the medical records on pregnancies and births were consistent with reported data. Validation primarily helps ensure that clinics are being careful to submit accurate data. It also serves to identify any systematic problems that could cause data collection to be inconsistent or incomplete.
The data validation process does not include any assessmgent of clinical practice or overall record keeping. See Appendix A, Technical Notes, for a more detailed presentation of findings from the validation visits.
14. How does CDC use the variables/data collected but not reported in the annual Assisted Reproductive Technology Success Rates National Summary and Fertility Clinic Reports?
CDC uses the data collected and not reported in the annual assisted reproductive technology (ART) report to evaluate emerging ART research questions and to monitor safety and efficacy issues related to ART treatment for improving maternal and child outcomes. Other data may not be released in order to protect the ART patient’s confidentiality. Review a list of ART publications.
15. How does CDC ensure the confidentiality of the assisted reproductive technology data it collects?
CDC has an Assurance of Confidentiality for the Assisted Reproductive Technology (ART) database. An Assurance of Confidentiality is a formal confidentiality protection authorized under Section 308(d) of the Public Health Service Act (42 U.S.C. 242[m]). An assurance is used for projects conducted by CDC staff or contractors involving the collection or maintenance of sensitive identifiable or potentially identifiable information. The assurance allows CDC programs to assure individuals and institutions involved in research or non-research projects that those conducting the project will protect the confidentiality of the data collected. Under PHSA Section 308(d), no identifiable information may be used for any purpose other than the purpose for which it was supplied unless such institution or individual has consented to that disclosure. CDC’s current assurance of confidentiality for this project is ongoing.
This report describes a woman’s average chances of success using ART. Although the report provides some information about factors such as age and infertility diagnosis, individual couples face many unique medical situations. This population-based registry of ART procedures cannot capture detailed information about specific medical conditions associated with infertility. A physician in clinical practice should be consulted for the individual evaluation that will help a woman or couple understand their specific medical situation and their chances of success using ART.
17. Why are summary statistics in the Fertility Clinic tables published by CDC different from summary statistics reported in the SART National Summary?
From 1996–2008, the percentage of ART clinics reporting data to CDC with a SART membership ranged from approximately 86% to 95%. Annual summary statistics of ART treatments performed in each of these clinics are available online at www.sart.org. Although the same table items are used in both the CDC’s Fertility Clinic Tables and SART National Summary, discrepancies in tabulated statistics between the SART and CDC tables may be due to (1) the inclusion, in the CDC tables, of ART treatments performed at non-SART member clinics; (2) differences in the data submission deadlines between SART and CDC. Differences in submission dates may result in ART clinics being excluded from the CDC annual report but not from the SART National Summary report; and (3) differences in data processing procedures and statistical methods used to generate statistics.
CDC collects only information on the age of egg donors, but does not present it in the individual clinic tables for this report. In 2008, the average age of egg donors was approximately 28 years old. Success rates for cycles using donor eggs or using embryos derived from donor eggs are presented separately based on the ART patient’s age.
The American Society for Reproductive Medicine (ASRM) and SART issue guidelines dealing with specific ART practice issues, such as the number of embryos to be transferred in an ART procedure. Further information can be obtained from ASRM or SART (both at telephone 205-978-5000).
For further information on specific clinics, contact the clinic directly (see Appendix C for current contact information). In addition, SART can provide general information on its member clinics (telephone 205-978-5000, extension 109).
Overall, the content and format of this report are similar to those used in previous years. New information includes the following:
- Percentages of ART Cycles That Resulted in Live Births, by Type of ART and Clinic Size (Section 1: Overview—Figure 5)
- Percentages of Embryos Transferred That Resulted in Implantation Among Women Using Fresh Nondonor Eggs or Embryos, by Age Group (Section 2: Fresh Nondonor Cycles—Figure 34)
- Percentages of Embryos Transferred That Resulted in Implantation Among Women Using Frozen Nondonor Embryos, by Age Group (Section 3: Frozen Nondonor Cycles—Figure 43)
- Numbers of ICSI Procedures Performed, by Type of ART Cycle (Section 5: ART Trends—Figure 52)
- Percentages of Transfers That Resulted in Live Births, by Type of ART Cycle and ICSI (Section 5: ART Trends—Figure 53)
- Percentages of Transfers That Resulted in Singleton Live Births, by Type of ART Cycle and ICSI (Section 5: ART Trends—Figure 54)
National Summary and Individual Fertility Clinic Tables
- The ART Cycle Profile section now includes summary statistics for cycles with eSET (elective single-embryo transfer).
- The Pregnancy Success Rates section now includes the percentage of embryos transferred that resulted in implantation among women using fresh embryos from nondonor eggs. This information is broken down by age group.
Note: The purpose of adding the new measures is to provide a more comprehensive report to help potential ART users make informed decisions.
Glossary of Terms
- New definitions for Implantation Rate and eSET (elective single-embryo transfer).
- Updated definitions for Miscarriage and Stillbirth.