What is assisted reproductive technology (ART)?

ART includes all fertility treatments in which either eggs or embryos 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 a female patient or gestational carrier or donating them to another patient.

The main type of ART is in vitro fertilization (IVF). IVF involves extracting a woman’s eggs, fertilizing the eggs in the laboratory, and then transferring the resulting embryos into the uterus of the female patient or gestational carrier. 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.

In addition, ART often is categorized according to whether the procedure was started with the intent to freeze all eggs or embryos (banking), whether the procedure used a female patient’s own eggs (nondonor) 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 (frozen).

What is an ART cycle?

Because ART consists of several steps over an interval of approximately 2 weeks, 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 when a woman begins taking drugs to stimulate egg production or starts ovarian monitoring with the intent of having embryos transferred. For the purposes of this report, 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.

How do United States ART clinics report data to CDC about their success rates?

CDC contracts with a statistical survey research organization, Westat, to obtain the data published in the Fertility Clinic Success Rates Report. Westat maintains a list of all ART 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 ART 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. SARTmember clinics can report directly to SART, and SART submits the data to NASS. The data collected include de-identified information on the patient’s medical history (such as infertility diagnoses), clinical information pertaining to the ART procedure, and information on resulting pregnancies and births.

Why is the data of 2017 success rates being published in 2019?

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 possible date that clinics can report complete annual data is about 9 months past the end of the reporting year, when all the births have occurred. Accordingly, the results of all the cycles initiated in 2017 were not known until October 2018. After ART outcomes are known, the following occurs before the report is published:
• Clinics enter their 2017 data into NASS and verify that the generated clinic tables are accurate before submitting the data at the end of 2018.
• Preliminary data for individual fertility clinic tables are prepared and made available in the spring of 2019 on CDC’s website.
• After CDC conducts extensive data checks, the full report with all fertility clinic tables and the National Summary table is prepared and published on the CDC website.

Which clinics are represented in this report?

The data in this report come from 448 fertility clinics that provided and verified information about the outcomes of the ART cycles. Although almost all clinics that provided ART services in the United States during 2017 are represented in this report, data from 50 clinics or individual providers are not included because they did not report as required. Clinics known to have been in operation at any time during 2017 that did not report and verify their data are listed in this report as nonreporters, as required by law. Given the estimated number of ART cycles performed in nonreporting clinics, we estimate that ART surveillance covered 98% of ART cycles performed in the United States in 2017. We will continue to make every effort to include in future reports all clinics that provide ART services.

How are the success rates determined?

Because this report is geared toward patients, the focus is on live birth success rates. Singleton live births (births of a single, live infant), are emphasized 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. This report presents several measures of success for ART, including the percentage of live births among ART cycles in which at least one egg or embryo is transferred to a patient or gestational carrier. Note that not all transfers cycles result in a pregnancy, and not all pregnancies result in a live birth. All live-birth deliveries were reported to the ART clinic by either the patient or the patient’s obstetric provider.

What are my chances of getting pregnant using ART?

Many consumers ask this question because they assume that a 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; some pregnancies result in miscarriage or stillbirth. The percentage of cycles resulting in live births based on the overall number of cycles performed to retrieve eggs or to transfer eggs or embryos 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 ART success rates vary in the context of 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.

What quality control steps are used to ensure data accuracy?

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 generated clinic tables are accurate. Then, Westat conducts an in-house review of the data and contacts the clinics if corrections are necessary. After the data have been checked, a quality control process called validation begins. In 2017, 34 (almost 8%) of the 448 reporting clinics were selected for validation. During the annual validation process, members of the Westat Validation Team visit the selected clinics and review medical record data for a sample of the clinic’s ART cycles. For each cycle, the validation team abstracts information from the patient’s medical record. The abstracted information is then compared with the data submitted for the report. The data validation process does not include any assessment of clinical practice or overall record keeping. 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.

Glossary of success rates for all patients (with or without prior ART cycles)

• Percentage of transfers resulting in live births

This is the percentage of egg or embryo transfers that resulted in a live birth. The denominator for this measure includes the number of transfers described above. The numerator includes the live birth(s) that resulted from the transfer(s) of eggs or embryos. For example, if 60 intended retrievals were associated with 58 transfers within 12 months, which resulted in 30 live births, the average success rate per transfer would be 30 (live births) ÷ 58 (transfers) = 0.517, or 51.7% of transfers resulting in a live birth.

• Percentage of transfers resulting in singleton live births

This is the percentage of transfers that resulted in the birth of a single live infant. The denominator for this measure includes number of transfers described above. The numerator includes singleton live births that resulted from the transfer(s) of eggs or embryos. For example, if 60 intended retrievals were associated with 58 transfers within 12 months, which resulted in 24 singleton live births, the average success rate per transfer would be 24 (singleton live births) ÷ 58 (transfers) = 0.414, or 41.4% of transfers resulting in a singleton live birth.

• Average number of transfers per intended retrieval

This is the average number of transfers of eggs or embryos that occurred per intended retrieval, among patients with no prior ART cycles. The denominator is the number of total intended retrievals among new patients. The numerator is the total number of transfers within 12 months after intended retrievals among new patients. For example, there were 55 transfers after 45 intended retrievals among new patients in 2016. Therefore, the average number of transfers per intended retrieval would be 55 (transfers) ÷ 45 (intended retrieval) = 1.2 transfers per intended retrieval among patients with no prior ART cycles.

Glossary of success rates for ART transfers among patients using eggs or embryos from a donor

Success rates presented in this section are based on donor cycles that had egg or embryo transfers in 2017, regardless of retrieval date. For example, an ART donor cycle that starts as an intended retrieval in March 2016 and has an embryo transfer in 2017 will be included in the 2017 report. This section also includes cycles in which intended parents transferred donated embryos in 2017 but do not know the date of egg retrieval. This section excludes cycles that were considered research—that is, cycles performed to evaluate new procedures. Success rates are not presented by age group because previous data show that an intended parent’s age does not substantially affect success when using donor eggs or donated embryos. The success rates are presented by types of embryos and eggs used in the transfer.

• Fresh embryos, fresh eggs

This is ART cycles involving fresh embryos created from fresh donor eggs. The eggs were retrieved from a donor and fertilized (if applicable) during the current cycle. Neither the donated eggs nor any resulting embryos were ever frozen prior to transfer.

• Fresh embryos, frozen eggs

This is ART cycles involving fresh embryos created from frozen donor eggs. The eggs were retrieved from a donor during a previous cycle and frozen for future use. The eggs were then thawed, fertilized (if applicable), and transferred in 2017. The donated eggs were frozen prior to transfer, but any resulting embryos were not.

• Frozen embryos

This is ART cycles involving frozen embryos created from fresh or frozen donor eggs. In the case of fresh donor eggs, the eggs were retrieved from a donor during a previous cycle and fertilized, and then the resulting embryo was frozen for future use. In the case of frozen donor eggs, the eggs were retrieved from a donor during a previous cycle, frozen, thawed, and fertilized, and then the resulting embryos were frozen for future use. For both fresh and frozen donor eggs, the frozen embryos were thawed for transfer in 2017.

• Donated embryos

This is ART cycles involving donated embryos— that is, embryos donated from another patient or couple after their own ART treatment. The embryos can be fresh or frozen.

• Percentage of transfers resulting in live births

This is the percentage of transfers in 2017 of at least one donor egg or embryo that resulted in a live birth. The denominator includes the number of transfers described above. The numerator includes the live birth(s) that have resulted from the transfer(s) of donated eggs or embryos. For example, if 20 transfers using at 19 least one donor egg or embryo resulted in 10 live births, the average success rate per transfer would be 10 (live births) ÷ 20 (transfers) = 0.5, or 50.0% of donor egg or embryo transfers resulting in a live birth.

• Percentage of transfers resulting in singleton live births

This is the percentage of transfers in 2017 of at least one donor egg or embryo that resulted in the birth of a single live infant. The denominator includes the number of transfers described above. The numerator includes singleton live births that have resulted from the transfer(s) of donated eggs or embryos. For example, if 20 transfers using at least one donor egg or embryo resulted in 8 singleton live births, the average success rate per transfer would be 8 (singleton live births) ÷ 20 (transfers) = 0.4, or 40.0% of donor egg or embryo transfers resulting in a singleton live birth.

• Total number of cycles

This is the number of ART cycles started in 2017 by age group and in total. The total number of ART cycles is calculated as the sum of (1) the number of cycles started with the intent to freeze all resulting eggs or embryos (for example, short term banking or fertility preservation); (2) the number of cycles started with the intent to transfer fresh or frozen eggs retrieved from either the patient or donor; and (3) the number of cycles started with the intent to transfer fresh or frozen embryos created from fresh or frozen eggs retrieved from either the patient or donor.

• Percentage of transfers using a gestational carrier

This is the percentage of transfers in which the intended parent does not intend to carry the pregnancy but rather use a gestational carrier. A gestational carrier (also known as a gestational surrogate) is a woman who gestates an embryo that was formed from the egg of another woman with the expectation of returning the infant to its intended parent(s). The eggs or embryos can be either fresh or previously frozen and thawed and may come from either intended parents or donors. The denominator includes all cycles in which at least one egg or embryo was transferred. The numerator includes the total number of transfers in which the pregnancy carrier was a gestational carrier.

• Percentage of transfers using frozen embryos

This is the percentage of transfers in which at least one frozen embryo created from either fresh or frozen eggs was transferred to the intended parent or gestational carrier. The denominator includes all cycles in which at least one egg or embryo was transferred. The numerator includes all transfers that included at least one frozen embryo.

• Percentage of transfers of at least one embryo with ICSI

This is the percentage of transfers in which at least one embryo was fertilized using ICSI (intracytoplasmic sperm injection). ICSI is a procedure in which a single sperm is injected directly into an egg for fertilization. It is an alternative to conventional in vitro fertilization in which sperm compete to fertilize an egg. Transferred embryos may be fresh or frozen and may use fresh or frozen eggs retrieved from the intended parent or donor. The denominator includes all cycles in which at least one egg or embryo was transferred. The numerator includes all transfers in which ICSI was performed.

• Percentage of transfers of at least one embryo with PGT

This is the percentage of transfers in which at least one embryo underwent PGT (preimplantation genetic testing). PGT is used to detect chromosomal or genetic abnormalities and prevent transmission of inherited diseases. The denominator includes all cycles in which at least one egg or embryo was transferred. The numerator includes all transfers in which PGT was performed on at least one embryo.

Glossary of reasons for using ART

This section reports the reasons for using ART among cycles started in 2017.
Percentages may add to more than 100% because there may be more than one reason or diagnosis that can be reported for each ART cycle. This section excludes cycles performed to evaluate new procedures.

• Male factor
This is the percentage of cycles started for intended parents that have a diagnosis of infertility due to low sperm count or problems with sperm function in male patients that makes it difficult for a sperm to fertilize an egg under normal conditions.

• Endometriosis
This is the percentage of cycles started for patients that have a diagnosis of endometriosis, which is described as a history of a medical condition that involves the presence of tissue similar to the uterine lining outside the uterus.

• Tubal factor
This is the percentage of cycles started for patients that have a diagnosis of blocked or damaged fallopian tubes, which makes it difficult for an egg or embryo to travel to the uterus.

• Ovulatory dysfunction
This is the percentage of cycles started for patients whose ovaries are not producing eggs normally. Ovulatory dysfunction is characterized by irregular menstrual cycles reflective of ovaries that are not producing one mature egg each month. It includes polycystic ovary syndrome and functional hypothalamic amenorrhea.

• Uterine factor
This is the percentage of cycles started for patients with a structural or functional disorder of the uterus that results in reduced fertility.

• PGT
This is the percentage of cycles started for patients whose primary reason for using ART was for conducting PGT, which includes diagnosis or screening to detect chromosomal or genetic abnormalities and prevent an inherited disease. This includes cycles performed for aneuploidy screening.

• Gestational carrier
This is the percentage of cycles started for intended parents using a gestational carrier— that is, a woman who gestates an embryo formed from the egg of either the intended parent or a donor with the expectation of returning the infant to its intended parent(s).

• Diminished ovarian reserve This is the percentage of cycles started for patients with a decreased number of available eggs. Reasons include congenital, medical, or surgical causes or advanced age.

• Egg or embryo banking
This is the percentage of cycles started for intended parents using ART for the purpose of freezing eggs or embryos for future use.

• Recurrent pregnancy loss
This is the percentage of cycles started for patients that have recurrent pregnancy loss, described as two or more failed pregnancies.

• Other, infertility
This is the percentage of cycles started for intended parents using ART with a diagnosis for a known reason that is not listed; this diagnosis was related to infertility.

• Other, non-infertility
This is the percentage of cycles started for intended parents using ART with a diagnosis for a known reason that is not listed, but was NOT related to infertility.

• Unexplained
This is the percentage of cycles started for intended parents with infertility but for which no cause of infertility was found.

Resource:

2017 Assisted Reproductive Technology Fertility Clinic Success Rates Report