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Commonly Asked Questions
The latest published data on infertility in the United States available to CDC are from the 2015–2019 National Survey of Family Growth. Key findings from this survey include the following:
- About 19% of married women aged 15 to 49 years with no prior births are unable to get pregnant after 1 year of unprotected intercourse (infertility).
- About 26% of married, women aged 15 to 49 years with no prior births have difficulty getting pregnant or carrying a pregnancy to term (impaired fecundity).
- About 12% of all women aged 15 to 49 years have ever received any infertility services.
For more details, see the National Survey of Family Growth website.
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 either eggs or embryos are handled outside a woman’s body.
In general, ART procedures involve surgically removing eggs from a woman’s ovaries, combining them with sperm in the laboratory, and returning them to a female patient or a gestational carrier or donating them to another patient. They do NOT include treatments in which only sperm are handled (such as intrauterine insemination) or procedures in which a woman takes drugs only to stimulate egg production without the intention of having eggs surgically retrieved.
The main type of ART is in vitro fertilization (IVF). For some IVF procedures, fertilization involves a specialized technique known as intracytoplasmic sperm injection (ICSI). In ICSI, a single sperm is injected directly into a woman’s egg.
Other types of ART exist but are rarely performed. Gamete intrafallopian transfer (GIFT) involves using a fiber optic instrument called a laparoscope to guide the transfer of unfertilized eggs and sperm (gametes) into a woman’s fallopian tubes through small incisions in her abdomen. Zygote intrafallopian transfer (ZIFT) involves fertilizing a woman’s eggs in the laboratory and then using a laparoscope to guide the transfer of the fertilized eggs (zygotes) into a woman’s fallopian tubes.
In addition, ART is often categorized according to whether the procedure involved freezing all eggs or embryos (banking), whether the procedure used a patient’s own eggs or eggs from another woman (donor), whether the eggs were frozen and thawed before use, and whether the embryos used were newly fertilized (fresh) or previously fertilized, frozen, and then thawed.
Because ART consists of several steps, an ART procedure is typically referred to as a cycle of treatment rather than a procedure at a single point in time. The start of an ART cycle is usually when a woman begins taking medication to stimulate egg production or begins monitoring with the intent of having embryos transferred. If eggs are produced, the cycle progresses to egg retrieval. Retrieved eggs can be combined with sperm to create embryos or frozen for future use. If fertilization is successful, embryos can be selected for transfer in the same cycle or frozen for future use. If embryo transfer results in implantation, the cycle may progress to clinical pregnancy and possibly a live-birth delivery. For the purposes of ART reporting, data on all cycles that were started, even those that were discontinued before all steps were undertaken, are counted in the clinic’s success rates.
CDC contracts with a statistical survey research organization, Westat, to obtain the data published in this 2021 Assisted Reproductive Technology Fertility Clinic and National Summary Report and on the ART Success Rates website (hereafter called the ART reports when discussed collectively in this publication). Westat maintains a list of all fertility clinics known to be in operation, identifies new clinics throughout the year, 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 maintains the National ART Surveillance System (NASS), the web-based data collection system that all fertility clinics use to submit data to CDC. Clinics either electronically enter or import data into NASS for each ART cycle started in a given reporting year. SART member clinics can report directly to SART, and their data are imported into NASS. The data collected include de-identified information on the patient’s medical history (such as infertility diagnoses), clinical information related to the ART procedure, and information on resulting pregnancies and births.
Before success rates based on live-birth delivery can be calculated, every ART pregnancy must be followed up to determine whether a birth occurred. Therefore, the earliest possible date that clinics can report ART outcomes is about 9 to 10 months past the end of the reporting year, when all births have occurred. Thus, the results of all cycles started in a given year (year 1) are not known until about September or October of the following year (year 2).
After ART outcomes are known, the following occurs before ART reports are published:
- Clinics enter their data into NASS and verify that the generated clinic tables are accurate before submitting the data at the end of year 2.
- After CDC conducts extensive data checks, the ART Fertility Clinic Success Rates and dataset are published at the end of year 3.
The ART reports contain statistics on two types of measures—noncumulative (or yearly) measures and cumulative measures. While calculations of noncumulative yearly measures (such as success rates for patients using donor eggs or embryos and general patient and cycle characteristics) are based on ART cycles performed in 2021, the calculation of cumulative success rates for patients using their own eggs requires data from two reporting years (2020 and 2021).
Cumulative success rates for patients using their own eggs represent the chance of having a baby after considering embryo transfers that occur within 1 year after an egg retrieval (either intended or actual). The cumulative success rate calculation requires a follow-up period of about 21 to 22 months after egg retrieval: 12 months for embryo transfers and 9 to 10 months for outcomes of these transfers to occur.
To calculate cumulative success rates for patients using their own eggs, we used complete information on all transfers and resulting outcomes occurring in 2020 and 2021 for patient egg retrievals that occurred in 2020. For clinics that did not report data during the previous reporting year, cumulative success rates for patients using their own eggs cannot be calculated, and only noncumulative success rates are published.
For more information on the calculation of cumulative success rates for patients using their own eggs, see question 11.
The data in the ART reports come from 453 fertility clinics that provided and verified information about the outcomes of the ART cycles performed in their clinics.
Although almost all clinics that provided ART services in the United States during 2021 are represented in the ART reports, data from 48 clinics or individual providers (9.6%) are not included because they did not report as required. Clinics known to have been in operation at any time during 2021 that did not report or verify their data are listed in this report as nonreporters, as required by law (see Appendix C, 2021 Nonreporting Clinics, by State).
Given the estimated number of ART cycles performed in nonreporting clinics, we estimate that ART surveillance covered about 98% of ART cycles performed in the United States in 2021.
Although the quality of ART services can affect the reported outcomes, patient characteristics such as age, race or ethnicity, infertility diagnosis, or existing medical conditions can also contribute to differences in ART success rates. For example, a clinic may accept patients that would be denied care from another clinic, which may result in lower success rates, even if the quality of care in the two clinics was identical.
Clinic-specific success rates provide information on ART use and the associated outcomes from each reporting clinic. However, differences in the success rates between clinics may not reflect differences in the quality of ART services.
Many factors contribute to the success of an ART procedure, and a difference in success rates between two fertility clinics may reflect differences in the characteristics of patients treated, the types of procedures performed, or other factors. More explanations on how to use the success rates and other statistics published in ART reports are in the How to Access and Interpret Fertility Clinic Success Rates section and on the ART Success Rates website.
This report should be used to help people considering an ART procedure find clinics where they can meet with ART providers to discuss their specific medical situation and their likelihood of success using ART. Contacting a clinic may also provide additional information that could be helpful in deciding whether to use ART. Because ART offers several treatment options, and because there are non-ART treatment options for infertility, many other factors may affect a person’s decision. This report may be a helpful starting point for consumers to obtain information and consider their options.
The ART reports include 413,776 new ART cycles performed in 2021 by the 453 clinics that reported their data as required. ART cycles started in 2021 are used to report on 2021 yearly measures (such as success rates for patients using donor eggs or embryos and general patient and cycle characteristics) and, in part, to report on cumulative success rates for patients using their own eggs from retrieval cycles performed in 2020. (See question 6 for additional details.) No cycles in which a new treatment procedure was evaluated were performed in 2021.
The ART reports present several measures of ART success, including the percentage of live-birth deliveries or singleton live-birth deliveries among all ART cycles or among ART cycles with at least one embryo transferred. Note that not all transfer cycles result in a pregnancy, and not all pregnancies result in a live-birth delivery.
Because the ART reports are geared toward patients, the focus is on a live-birth delivery outcome, which is the delivery of one or more live infants. Singleton live-birth delivery (birth of a single live infant) is shown as a separate measure of success because, compared to a multiple live-birth delivery, it has a lower risk of adverse outcomes for mothers and infants, including cesarean section, prematurity, low birth weight, and infant disability or death.
Because of changes in clinical practice and more variation in ART treatment options, including improvements in egg and embryo cryopreservation (freezing), the field of ART is moving toward reporting cumulative success rates whenever possible. In the ART reports, success rates for patients using their own eggs are shown as cumulative success rates. These rates are calculated after accounting for all transfers of embryos that occur within 1 year after an egg retrieval. Thus, the calculation of cumulative success rates includes ART cycles performed in 2020 and 2021.
For clinics that did not report data during the previous reporting year, cumulative success rates for patients using their own eggs cannot be calculated, and only noncumulative success rates are published.
For more details about the calculation of cumulative success rates for patients using their own eggs, see the ART Success Rates website.
Calculation of success rates for patients using donor eggs only includes ART cycles performed in 2021. For more details about the calculation of success rates for patients using donor eggs or embryos, see the ART Success Rates website.
ART success rates vary according to patient and treatment characteristics. These characteristics include age, type of infertility diagnosis, number of embryos transferred, type of ART procedure, use of techniques such as ICSI, and history of previous births, miscarriages, and ART cycles.
CDC’s Division of Reproductive Health has developed the In Vitro Fertilization (IVF) Success Estimator tool to estimate the chance of having a baby using IVF, the most common type of ART. Estimates are calculated based on the experiences of women and couples with similar characteristics.
To have their success rates published in the ART reports, clinics must submit their data in time for analysis, and the clinics’ medical directors must verify by signature that the generated clinic tables are accurate. Then, Westat reviews the data and contacts clinics if corrections are necessary. After the data have been checked, a quality control process called validation normally begins.
During the annual validation process, members of the Westat validation team meet with a selection of reporting clinics and review medical record data for a sample of the clinic’s ART cycles. For each cycle, the validation team reviews information from the patient’s medical record. The information collected is then compared with the data submitted for the ART reports. In recent years, approximately 35 reporting clinics (7% to 10% of all reporting clinics) have been randomly selected for validation.
The data validation process does not include any assessment of clinical practice or overall recordkeeping. Validation primarily helps ensure that clinics submit accurate data. It also serves to identify any systematic problems that could cause data collection to be inconsistent or incomplete.
CDC uses any data collected and not included in the annual ART reports to monitor emerging practice patterns, better understand success rates by the characteristics of the patient or practice, evaluate emerging ART research questions, and monitor safety and efficacy issues related to ART treatment in order to improve maternal and child health outcomes. CDC also uses these data in the IVF Success Estimator tool, State-Specific ART Surveillance report, and scientific publications on CDC’s ART website.
CDC has an Assurance of Confidentiality for the ART database. An assurance is a formal confidentiality protection used for projects conducted by CDC staff or contractors that involve the collection or maintenance of sensitive, identifiable, or potentially identifiable information. The assurance protects the confidentiality of individuals and institutions included in ART data. The ART data are stored in a secure, limited-access, password-protected environment.
The ART reports describe the average chances of success per ART cycle. Although the ART reports provide some information about factors such as age and type of infertility diagnosis, patients have many unique medical situations. This population-based registry of ART procedures cannot capture detailed information about specific medical conditions associated with infertility. Patients should talk with their doctor to understand their specific medical situation and their chances of success using ART.
In 2021, 80% of all fertility clinics reporting data to CDC were SART members. Annual summary statistics of ART treatments performed in each SART member clinic are available in CDC’s ART reports and on the SART website.
Discrepancies in tabulated statistics between CDC and SART tables may be due to (1) the inclusion of ART treatments performed at non-SART member clinics in CDC’s ART reports; (2) differences in data submission deadlines for CDC and SART, which may result in some fertility clinics being excluded from CDC’s ART reports; and (3) differences in data processing procedures, statistical methods, choice of reported measures, and data presentation.
When a woman seeks treatment for the purpose of donating her eggs, CDC asks clinics to report select demographic information on the donor and details on the stimulation and retrieval process. While CDC does not present data about egg donors in the ART reports, success rates for cycles using donor eggs or embryos derived from donor eggs are presented.
For more information on specific clinics, contact the clinic directly (see Appendix C: ART Clinics for contact information). SART can also provide general information about its member clinics (call 205-978- 5000 or visit the SART website).
Resources for people experiencing infertility can be found on CDC’s Infertility FAQs website under Related Links. CDC’s IVF Success Estimator tool is also available online. Resources for people interested in ART can be found on CDC’s What Is Assisted Reproductive Technology? website under Related Resources.
CDC continuously strives to present the most accurate and relevant ART fertility clinic success rates to help guide potential patients’ decisions. For the first time, the number of patients receiving ART treatments (in addition to the number of ART cycles) is included within the national summary statistics.