How to Read a Fertility Clinic Table
This section is provided to help consumers understand the information presented in the fertility clinic tables. The number before each heading refers to the number of the corresponding section in the sample clinic table. Technical terms are defined in the Glossary of Terms (Appendix B).
- Type of ART
This section gives the breakdown of ART cycle types that each clinic performed using fresh nondonor eggs or embryos (IVF, GIFT, ZIFT, or combinations thereof). It also lists the percentage of procedures that involved intracytoplasmic sperm injection (ICSI); the percentage of cycles that were unstimulated; the percentage of cycles that used a gestational carrier; the percentage of cycles that used preimplantation genetic diagnosis (PGD); and the percentage of cycles with elective single-embryo transfer (eSET). (See Glossary of Terms in Appendix B for definitions of IVF, GIFT, ZIFT, ICSI, unstimulated cycle, gestational carrier, PGD, and eSET.)
Consumers may want to know what percentage of a particular clinic’s patients have the same diagnosis as they do. (See Glossary of Terms in Appendix B for definitions of diagnoses.) In addition, patients’ diagnoses may affect a clinic’s success rates. However, the use of these diagnostic categories may vary somewhat from clinic to clinic.
To have success rates published in the annual report, a clinic’s medical director must verify the accuracy of the tabulated success rates. The name of the individual who verified the clinic’s data is shown.
- Success rates by type of cycle
Success rates are given for the three categories of cycles described in 4A–C below: cycles using fresh embryos from nondonor eggs, cycles using frozen embryos from nondonor eggs, and cycles using donor eggs. The ART success rates shown were calculated based on data from all ART cycle types (IVF, both with and without ICSI; GIFT; and ZIFT). Data from these procedures were combined because there was little difference in success rates when we examined each type of ART procedure separately.
The success rates indicate the average chance of success for the given procedure at the clinic in 2008 for each of five age groups. Success rates are calculated as the percentage of cycles started, egg retrievals, or embryo transfers that resulted in either pregnancies or live births at the ART clinic in 2008. For example, if a clinic started a total of 50 cycles in 2008 and these resulted in 15 live births, the average success rate for cycles started at that clinic would be
15 (births) ÷ 50 (cycles) = 0.3 or 30%.
Thus, the success rate at that clinic in 2008 was 30%, meaning that 30% of cycles started that year resulted in a live birth.
Success rate calculations are very unstable if they are based on a small number of cycles. Therefore, when fewer than 20 cycles are reported in a given category, the rates are shown as fractions rather than percentages. For example, the sample clinic performed only 19 fresh embryo cycles using nondonor eggs among women aged 41–42 years. Of these 19 cycles, 2—or 10%—were successful. However, because of the small number of cycles, 10% is not a statistically reliable success rate, so the success rate is presented as 2 / 19, meaning 2 out of 19.
This section includes IVF, ICSI, GIFT, and ZIFT cycles that used a woman’s own eggs. Cycles that used frozen embryos or donor eggs or embryos are not included here.
- Percentage of embryos transferred resulting in implantation
(The larger of either the number of maximum fetal hearts or maximum infants born [live births + stillbirths] divided by the number of embryos transferred, expressed as a percentage of embryo transfers)
This number represents the cycles that resulted in an intrauterine clinical pregnancy (numerator) out of the total number of embryos transferred (denominator) in which one or more embryos were transferred (denominator) into the woman’s uterus or fallopian tube in the case of GIFT and ZIFT cycles. Not all fetal hearts can be detected by ultrasound, for this reason, a positive intrauterine clinical pregnancy is defined as the larger of either the number of maximum fetal hearts by ultrasound or maximum infants born, including live births and stillbirths.
- Percentage of cycles resulting in pregnancies
(Number of pregnancies divided by number of cycles started, expressed as a percentage of cycles)
A stimulated cycle is started when a woman begins taking fertility drugs; an unstimulated cycle is started when egg production begins being monitored. The number of cycles that a clinic starts is not the same as the number of patients that it treats because some women start more than one cycle in a year. Because some pregnancies end in a miscarriage, induced abortion, or stillbirth, the percentage of cycles resulting in pregnancies is usually higher than the percentage of cycles resulting in live births.
- Percentage of cycles resulting in live births
(Number of live births divided by number of cycles started, expressed as a percentage of cycles)
This number represents the cycles that resulted in a live birth out of all ART cycles started. One live birth may include one or more children born alive; that is, a multiple-infant birth (e.g., twins, trplets) is counted as one live birth.
- Percentage of retrievals resulting in live births
(Number of live births divided by number of egg retrieval procedures, expressed as a percentage of retrievals)
This number represents the cycles that resulted in a live birth out of all cycles in which an egg retrieval was performed. The number of egg retrievals a clinic performs often is smaller than the number of cycles started because some cycles are canceled before the woman has an egg retrieved. As a result, the percentage of retrievals resulting in live births is usually higher than the percentage of cycles resulting in live births. Cycles are canceled for many reasons: eggs may not develop, the patient may become ill, or the patient may choose to stop treatment (see Figure 7).
of transfers resulting in live births
(Number of live births divided by number of embryo transfer procedures, expressed as a percentage of transfers)
This number represents the cycles that resulted in a live birth out of all cycles in which one or more embryos were transferred into the woman’s uterus or, in the case of GIFT and ZIFT, egg and sperm or embryos were transferred into the woman’s fallopian tubes. A clinic may perform more egg retrievals than embryo transfers because not every retrieval results in egg fertilization and embryo transfer. For this reason, the percentage of transfers resulting in live births generally will be higher than those reported for egg retrievals and for cycles started.
- Percentage of transfers resulting in singleton live births
(Number of singleton live births divided by number of embryo transfer procedures, expressed as a percentage of transfers)
This number represents the cycles that resulted in the birth of a single infant out of all cycles in which one or more embryos were transferred into the woman’s uterus or, in the case of GIFT and ZIFT, egg and sperm or embryos were transferred into the woman’s fallopian tubes. Singleton births have a much lower risk than multiple-infant births for adverse infant health outcomes, including prematurity, low birth weight, disability, and death.
- Percentage of cancellations
(Number of cycles canceled divided by the total number of cycles, expressed as a percentage of cycles)
This number refers to the cycles that were stopped before an egg was retrieved. A cycle may be canceled if a woman’s ovaries do not respond to fertility medications and thus do not produce a sufficient number of follicles. Cycles also may be canceled because of illness or other medical or personal reasons (see Figure 7).
- Average number of embryos transferred
(Average number of embryos per embryo transfer procedure)
The average number of embryos transferred varies from clinic to clinic. The American Society for Reproductive Medicine (ASRM) and the Society for Assisted Reproductive Technology (SART) have practice guidelines that address this issue.
- Percentage of pregnancies with twins
(Number of pregnancies with two fetuses divided by the total number of pregnancies, expressed as a percentage of pregnancies)
A pregnancy with two fetuses is counted as one pregnancy.
of pregnancies with triplets or more
(Number of pregnancies with three or more fetuses divided by the total number of pregnancies, expressed as a percentage of pregnancies)
Pregnancies with multiple fetuses can be associated with increased risk for mothers and infants (e.g., higher rates of caesarean section, prematurity, low birth weight, infant death) and the possibility of multifetal pregnancy reduction.
A pregnancy with three or more fetuses is counted as one pregnancy.
of live births having multiple infants
(Number of deliveries resulting in a birth of more than one infant divided by the number of live births, expressed as a percentage of live births)
A delivery of one or more live-born infants is counted as one live birth.
Frozen (cryopreserved) embryo cycles are those in which previously frozen embryos are thawed and then transferred. Because frozen embryo cycles use embryos formed from a previous stimulated cycle, no stimulation or retrieval is involved. As a result, these cycles usually are less expensive and less invasive than cycles using fresh embryos. In addition, freezing some of the embryos from a retrieval procedure may increase a woman’s overall chances of having a child from a single retrieval.
4C. Cycles using donor eggs
Success rates are presented separately for cycles using fresh donor eggs or embryos and those using frozen donor embryos. Older women, women with premature ovarian failure (early menopause), women whose ovaries have been removed, and women with a genetic concern about using their own eggs may consider using eggs that are donated by a young, healthy woman. Embryos donated by couples who previously had ART also may be available. Many clinics provide services for donor egg and embryo cycles. For these cycle types, results from women in all age groups (including older than 44) are reported together because previous data show that patient age does not affect success rates with donor eggs (see Figures 47 and 48).
Because a woman’s fertility declines with age, clinics report lower success rates for older women attempting to become pregnant with their own eggs. For this reason, rates for women using nondonor eggs or embryos are reported separately for women younger than age 35, for women 35–37, for women 38–40, for women 41–42, and for women 43–44. Clinic-specific outcome rates are not shown for women older than 44 who undergo ART using their own eggs because the number of women in this age group at each clinic is small; therefore, a calculation of the percentage of cycles resulting in live births in older age groups may not be meaningful. Readers are encouraged to review national outcomes for these age groups shown in Figure 16. The sample clinic table illustrates the decline in ART success rates among older women. For example, for cycles that used fresh embryos from nondonor eggs, the percentage of cycles resulting in live births among women younger than 35 was 37.4%, whereas the percentage of cycles resulting in live births among women 38–40 was 20.6%.
The tables show a range, called the 95% confidence interval, that conveys the reliability of a clinic’s demonstrated success rate. This range is calculated only if 20 or more cycles are reported in an age category. (When fewer than 20 cycles are reported in a given category, success rates are shown as fractions rather than percentages, see success rates by type of cycle.) In general, the more cycles that a clinic performs, the narrower the range. A narrow range means we are more confident that a clinic would have a similar success rate if it treated other similar groups of patients under similar clinical conditions. On the other hand, a wide range tells us that a clinic’s success rate is more likely to vary under similar circumstances because we had less information (fewer cycles) on which to base our estimates. Even though one clinic’s success rate may appear higher than another’s based on the confidence intervals, these confidence intervals are only one indication that the success rate may be better. Other factors also must be considered when comparing rates from two clinics. For example, some clinics see more than the average number of patients with difficult infertility problems, whereas others discourage patients with a low probability of success.
For further information see, important factors to
consider when using the tables to assess a clinic.
See Appendix A for a more detailed explanation and examples of confidence intervals.
- Current name. This name reflects name changes that may have occurred since 2008, whereas the clinic name at the top of the table was the name of the ART clinic as it existed in 2008. Some clinics not only have changed their names but have reorganized as well. Reorganization is defined as a change in ownership or affiliation or a change in at least two of the three key staff positions (practice director, medical director, or laboratory director). In such cases, no current name will be listed, but a statement will be included that the clinic has undergone reorganization since 2008. Also, in such cases, no current clinic services or profile will be listed.
- Donor egg program. Some clinics have programs for ART using donor eggs. Donor eggs are eggs that have been retrieved from one woman (the donor) and then transferred to another woman who is unable to conceive with her own eggs (the recipient). Policies regarding sharing of donor eggs vary from clinic to clinic.
- Donor embryo. These are embryos that were donated by another couple who previously underwent ART treatment and had extra embryos available.
- Single women. Clinics have varying policies regarding ART services for single (unmarried) women.
- Gestational carriers. A gestational carrier is a woman who carries a child for another woman; sometimes such women are referred to as gestational surrogates. Policies regarding ART services using gestational carriers vary from clinic to clinic. Some states do not permit clinics to offer this service.
- Cryopreservation. This item refers to whether the clinic has a program for freezing extra embryos that may be available from a couple’s ART cycle.
- SART member. In 2008, 375 of the 436 reporting clinics were Society for Assisted Reproductive Technology (SART) members.
- Verified lab
accreditation. If “yes” appears next to this item, the ART clinic uses an embryo laboratory accredited by one of the following organizations:
- College of American Pathologists (CAP)/American Society for Reproductive Medicine (ASRM), Reproductive Laboratory Accreditation Program.
- The Joint Commission (formerly the Joint Commission on Accreditation of Healthcare Organizations.
- New York State Tissue Bank Program (NYSTB).
If “pending” appears here, it means that the clinic has submitted an application for accreditation to one of the above organizations and has provided proof of such application to Westat. “No” indicates that the embryo laboratory has not been accredited by any of these three organizations.
CDC provides this information as a public service. Please note that CDC does not oversee any of these accreditation programs. They are all nonfederal programs. To become certified, laboratories must have in place systems and processes that comply with the accrediting organization’s standards. Depending on the organization, standards may include those for personnel, quality control and quality assurance, specimen tracking, results reporting, and the performance of technical procedures. Compliance with these standards is confirmed by documentation provided by the laboratory and by on-site inspections. For further information, consumers may contact the following accrediting organizations directly:
- CAP/ASRM, Reproductive Laboratory Accreditation Program: For a list of accredited laboratories, call 800-323-4040 and ask for Laboratory Accreditation.
- The Joint Commission: Call 630-792-5800 to inquire about the status of individual laboratories.
- New York State: Call 518-485-5341 to find out which laboratories are certified under the tissue bank regulations.
Further information on laboratory accreditation is provided in Appendix C.