Our Pregnancy Rates
Pregnancy rates for NYU Langone’s Fertility Center are available from the Society for Assisted Reproductive Technology (SART). Here is some information to help you understand the report’s summary.
Guide to Reporting Terminology
The number of assisted reproductive technology (ART) cycles that are reported to SART may include in vitro fertilization (IVF), gamete intrafallopian transfer, and zygote intrafallopian transfer.
Statistics from NYU Langone’s Fertility Center relate to IVF cycles using fresh and frozen embryos. The statistics we report to SART include:
- Cycles using fresh embryos from nondonor eggs: Embryos are created when a woman's eggs are harvested and fertilized in our laboratory. Fresh embryos are returned to her uterus during the same IVF cycle.
- Cycles using fresh embryos from donor eggs: When a woman doesn’t produce her own eggs or the quality is poor, eggs are retrieved from a known or anonymous donor and fertilized with sperm from the recipient couple. The embryos are transferred into the uterus of the recipient female.
- Cycles using frozen embryos from donor or nondonor eggs: When more embryos are created than are transferred back to the recipient female during an IVF cycle, the extra embryos can be cryopreserved for future embryo transfer.
Age is an important factor affecting a woman's chances for success with IVF. The probability of having a child begins to diminish after age 35 and falls dramatically beyond 41, and miscarriage rates increase with age. Although positive results are possible for women over 41, the chance of success is substantially decreased without the use of donor eggs. However if we are able to obtain a chromosomally normal embryo, we achieve pregnancy rates comparable to that with an egg donor, independent of the patient’s age.
In consideration of age-related variations, our statistics are broken down by SART into the following age categories:
- younger than 35
- 35 to 37
- 38 to 40
- 41 to 42
- 43 and older
Live Births Per Retrieval
Live births per retrieval is the number or percentage of live births that result from the total number of egg retrievals performed. This percentage is higher than that of live births resulting from initiated cycles, because sometimes a cycle is started but the ovaries do not respond sufficiently. In these cases, the cycle is canceled because there are too few eggs to retrieve.
Understanding the Statistics
As a member of SART and the American Society for Reproductive Medicine, NYU Langone’s Fertility Center reports ART cycle statistics annually. The traditional three-year lag in reports published by the Centers for Disease Control and Prevention has been shortened by a new electronic reporting process. However, collecting live birth statistics for cycles initiated in one particular year always continues into the next in order to record the birth of babies conceived in the previous year.
ART cycle outcomes are measured in very different ways, so it’s important to understand the statistical subtleties when comparing a clinic's success rates to others. Also, the reported outcomes relate only to ART cycles and do not reflect live births that result from other infertility therapies, such as artificial insemination with ovulation induction using fertility medications.
A program's success rate varies depending on the methodology used for reporting outcomes. Because statistics are collected at different stages of an ART cycle, and cycles may fail at various points for different reasons, successes reported at one stage may not be the same at the next. Only a percentage of ART cycles initiated result in pregnancy, and even fewer in a live birth.
The rate of live births can be calculated as a percentage of initiated cycles, egg retrievals, or embryo transfers, which can also determine a clinic’s success rate. For example, the percentage of live births per initiated cycle is lower than that of egg retrieval. Initiated cycles may be canceled before retrieval because there are not enough eggs, or the quality is too low, to make the surgery worthwhile.
Because most egg retrievals yield eggs and are used for an embryo transfer, many look at the pregnancy rate per embryo transfer as the primary way to evaluate success.