Pregnancy Rates for In Vitro Fertilization

IVF Pregnancy Rates

We are currently updating our statistics to provide the most recent information.

Guide to Reporting Terminology

Although ART cycles reported to SART can include IVF, GIFT (Gamete Intrafallopian Transfer) and ZIFT (Zygote Intrafallopian Transfer), our statistics above relate only to IVF cycles using fresh embryos. The statistics reported to SART may include:

  • Cycles using fresh embryos from nondonor eggs: embryos are created when the 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: in cases where a woman does not produce her own eggs, or the quality is poor, eggs are retrieved from a known or anonymous donor and fertilized with the 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 during an IVF cycle, the extra embryos can be cryopreserved for future embryo transfer.

Age Categories

Age is perhaps the single most 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, while 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. In consideration of age-related variations, our statistics are reported here in the following age categories:

  • Younger than 35 
  • 35-to-37
  • 38-to-40
  • 41-to-42 
  • 43 and older

Live Births Per Retrieval

This is the number or percentage of live births that resulted from the total number of successful egg retrievals. The percentage of live births per retrieval is higher than the percentage of live births resulting from initiated cycles because of cycle cancellations.

Understanding the Statistics

As a member of the Society for Assisted Reproductive Technology (SART) and the American Society for Reproductive Medicine, NYU Fertility Center reports ART cycle statistics annually. The traditional three-year lag in outcomes published by the Centers for Disease Control and Prevention has been narrowed by an electronic reporting process. However, collection of live birth statistics for cycles initiated in a particular year will continue into the next to capture the birth of babies conceived during the reporting period.

Because ART cycle outcomes are measured in very different ways, it is important to understand the statistical subtleties when reviewing a clinic's "success rates" and comparing the numbers with other ART programs. Also, the reported outcomes relate only to ART cycles and do not reflect live births that result from other infertility therapies.

A program's success rate will vary depending on the methodology used for reporting outcomes. Because statistics are collected at different stages of an ART cycle, and cycles fail at various points for different reasons, successes reported at one stage may not be carried over to the next. Only a percentage of the cycles initiated result in pregnancy, and even fewer in a live birth.

Because live births can be calculated as a percentage of initiated cycles, egg retrievals or embryo transfers, it is very important to consider the reporting methodology when comparing program outcomes. For example, the percentage of live births per initiated cycle is lower than the percentage of live births per retrieval. There are less retrievals than cycle starts because some cycles are cancelled prior to egg retrieval.

Also, a program's success rate can be dramatically influenced by its policies for cancelling cycles and by the number of embryos transferred. When reviewing SART or other statistics to compare programs, it is important to note these two numbers in addition to program outcomes.