Success varies with many factors. The age of the woman is
the most important factor, when women are using their own eggs. Success rates
decline as women age, specifically after the mid-30’s. Part of this decline is due to a lower chance
of getting pregnant from ART, and part is due to a higher risk of miscarriage
with increasing age, especially over age 40.
Success rates vary with the number of embryos transferred.
However, transferring more and more embryos at one time does not increase the
chance of live birth significantly, but may only increase the risk of a
multiple pregnancy, and its associated risks. The impact of the number of
embryos that are transferred also varies with the age of the woman.
SART, in conjunction with, The American Society for
Reproductive Medicine (ASRM), has published guidelines for the recommended
number of embryos to transfer (add to link). These guidelines are based on
SART-sponsored research which continually evaluates success rates around the
country. This helps to determine the
optimal number of embryos to transfer, based on specific patient characteristics,
like age and history of prior IVF.
Patients may require several cycles of treatment to have a baby. Success
rates remain fairly constant over several cycles, but may vary greatly between
It is important to
note that patient characteristics vary among programs; therefore, success rates
should not be used to compare treatment centers.