Why does it differ so much between clinics, and what does it mean?
Couples considering IVF can best evaluate and compare in vitro fertilization clinics when they have a thorough understanding of the outcome results of the program. Some IVF centers have very low pregnancy success rates. Other centres may have high success rates, but also a very high rate of triplet or higher multiple births. For these reasons, all couples considering IVF treatment should get a written statement of their clinic's recent success rates and evaluate them in relation to other clinics.
The four biggest variables affecting a program's IVF success rates are:
- The quality of the laboratory environment and the skill and experience of the embryology staff
- The skill and experience of the reproductive endocrinologist doctor (fertility specialist)
- The average number of embryos transferred per procedure
- The cases taken on by the program for IVF treatment. There are "good" patients and "bad" patients in the sense that some couples are more likely than others to have success from IVF because of egg quantity and quality, female age, or other issues.
Some programs are very aggressive and push their in vitro fertilization success rates up by transferring high numbers of embryos. Whether this is good or bad for the individual couple depends on whether the couple conceives, and if so - how many foetuses are present. A program that transfers high numbers of embryos may have a high overall success rate, but too many of these pregnancies will be triplets or quadruplets.
Triplet pregnancies are very high risk and need to be prevented as much as possible.
Risk of triplets, quadruplets, etc. is too great to justify transferring high numbers of embryos. We believe in balancing the risk of failure with the risk for high-order multiple pregnancies by transferring relatively fewer high quality embryos.
The appropriate number to transfer is decided on by the couple after a careful discussion with doctor regarding the quality of their embryos and the estimated risks for failure and for multiple pregnancies in their specific case.
Blastocyst transfer could essentially eliminate the problem of triplet and higher-order multiple pregnancies.
You should ask for information on IVF success rates and multiple pregnancy rates from any infertility specialist clinic that you are considering for IVF services. These issues are critical, and you have a right to the information.
You should also insist on live birth rates, not "pregnancy rates". The way a "pregnancy" is defined can vary between clinics, but we all know exactly what a live birth is.