"We know how to speak many falsehood which resemble real things, but we know, when we will, how to speak true things." Hesiod
No issue is as confusing or misleading as IVF success rates. Success rates can be easily manipulated to enhance a particular programs public image. Therefore, reported IVF statistics provide little meaningful guidance for an individual patient hoping to achieve pregnancy with IVF. While experts in the field and statisticians have acknowledged this, the public does not generally understand this and places increasing emphasis on the statistics from individual programs.
I am frequently asked "What's your IVF success rates?" The quick answer is somewhere between 0% to as high as 50%. Unfortunately, a meaningful answer is a lot more complicated. Obviously, success rates depend on how you define success and you calculate the total population.. Do you mean clinical pregnancy rate? (implantation seen on ultrasound) or ongoing pregnancy rate (fetal heart beat seen by ultrasound) or delivery? Will the denominator in this calculation be the number of couples entering treatment or those going to oocyte retrieval or those having pre-embryos replaced into the uterus. But its even more complicated than that. You are a unique individual with a unique medical history that affects your chance of having a baby. That is why any calculation requires additional information such as: duration of infertility, severity of infertility, your age and a host of other factors.
"Success rates" are often advertised or heralded by the media showing that a particular program has the "best success rates" in a given area supporting their claims with comparative data from publicly available data sources. Unfortunately few reporters or patients ask "How is this really done?" and instead choose to believe in miracle workers. While there are many talented individuals in the IVF field, there are no individuals, neither physicians or embryologists with supernatural powers.
So, how is this really done? What is really going on? To understand, we must keep in mind one of the essential principals of statistics. That is, statistics report data from POPULATIONS. Samples are taken, and averages are calculated. But, you are a PATIENT, not a POPULATION. You have a UNIQUE set of circumstances that will determine you own likelihood of achieving a pregnancy if you receive your medical care in an experienced IVF center. So, the key to good statistics is to have more ideal patients than difficult patients enter the program. To a large degree, the difference between a program with good statistics and one with less favorable pregnancy rates is more often due to the given mix of patient who present for treatment. But, earlier, I noted that these statistics can also be manipulated. Here is how it's done. By excluding or wait-listing individuals who've failed in other programs, are over 38 years old, have borderline FSH values, have prolonged unexplained infertility, or are low responders these programs can improve their statistics. By encouraging ART treatments for patients who are young, have had previous normal or ectopic pregnancies, regular menstrual cycles, limited or no prior treatment and have normal sperm factors pregnancy rates can also be increased. The pregnancy rates also depend on the number of pre-embryos transferred. A program that transfers a larger number of pre-embryos will likely report a higher pregnancy rate than one that judiciously restricts that number but the latter program will also experience far fewer complications due to multiple births.
So, how can couples with complex fertility problems make an informed choice? Unfortunately, the answer is not simple. You cannot rely solely on published statistics when seeking professional care. The misguided focus on "success rates" has created strong incentives, economic and otherwise, for IVF programs to maximize IVF statistics adopting some of the "gaming" tactics noted above. A better approach might be to:
Notwithstanding all of the above concerns, for those of you who are still interested in POPULATION statistics the following is submitted for review:
ARHC first 100 ART cycles (12/31/94)
ARHC / Dr. Perloe's Clinical Pregnancy Rate 52% (7/94-7/95)
Emory Center for Human Reproduction Clinical Pregnancy Rate 43%
