One of the most common questions that couples ask when they visit a fertility specialist is: “what is our chance of becoming pregnant?” While this is an excellent and very important question, it is not always possible to provide an answer that is based on specific data that applies to that couple.
The likelihood that a fertile couple will conceive within one Cycle is roughly 25% (cycle fecundity). When a couple is faced with a compromise to their fertility, this monthly rate of fertility may be approached, but it is unlikely to be exceeded by conventional types of fertility treatments that rely on Fertilization within the body, such as insemination. Many variables including age, sperm quality and unidentified pelvic factors, will affect the success of treatment, thereby making a prediction of fertility simply an educated estimate, rather than based on firm data.
However, this is not the case when a couple undergoes in vitro fertilization (IVF). With IVF most of the factors that prevent a couple from becoming pregnant are controlled, so that the outcome of treatment can be reliably predicted in the majority of cases. IVF success rates are strongly correlated with the age of the woman undergoing treatment and are reported based solely on this variable. Most high quality IVF programs report their data to the Society for Assisted Reproductive Technology (SART), which then provides this information to the Centers for Disease Control (CDC). The CDC publishes it as the Assisted Reproductive Technology (ART) report (http://www.cdc.gov/art/). This data is verified by IVF clinic directors and is subject to validation through random audits overseen by the CDC.
The ART report can be very useful in selecting a high quality IVF program, but a direct comparison of success rates to select the “best program” is not possible due to considerable variability in the types of patients who are treated. Individual clinics establish their own selection and cancellation criteria for the individuals that they will treat. One program may exclude a particular couple due to a less favorable prognosis, while another clinic might provide them with an opportunity to undergo treatment, even though their chance of success is predicted to be low. Other clinics might cancel treatment readily if the findings are not ideal. A high cancellation rate will lead to a higher pregnancy rate per Embryo transfer, since the cancelled cycles are not included in this calculation. The average number of embryos transferred will also impact the success rate of a fertility center. More embryos transferred could increase the program’s rate of success, but may also lead to a higher rate of multiple pregnancies which places the mother and babies at an increased risk of complications. Assessment of the rate of multiple pregnancies is important when evaluating these statistics.
One of the problems associated with this report is that even from the first day of publication, it is outdated. The outcomes (live births) of all treatment cycles from a given year are not known until October of the following year. It then takes several months to gather, enter and tabulate all of this data, making it nearly two years old at the time that it becomes available for review. In a field that is changing as rapidly as assisted reproduction, two years is a significant period of time, making it difficult to determine whether intervening changes in the center (laboratory, personnel, protocols) have had either a positive or negative impact on recent outcomes. The report is therefore helpful to identify good quality programs, but the published pregnancy rates may vary from more current results.
Another important consideration is the state in which the IVF clinic is located. At the present time, fifteen states mandate that insurance companies provide coverage for treatment of Infertility. While this is very helpful for many couples, it does encourage even those couples with a less favorable prognosis to seek treatment, as they will not suffer financially should treatment fail.
The size of a center should be a consideration, as clinics that treat more patients readily gain experience with more complicated and challenging clinical situations. This permits the center to evaluate the effectiveness of new protocols and embryologic techniques very quickly and incorporate these changes into practice based on personal experience, rather than simply based on what others have reported in the literature.
Two excellent measures of the overall quality of a program are its pregnancy rates using cryo-preserved (frozen) embryos and when donor eggs are used. High live birth rates using frozen embryos indicates that the embryology lab has an excellent culture system that is capable of maintaining the viability of the embryo both prior to and after it has been subjected to a freeze-thaw cycle. The overall efficiency of a single Stimulation cycle can be greatly increased when a center has a highly successful frozen embryo program. The pregnancy rate using donor eggs not only reflects the quality of the laboratory, but also the program as a whole, since many of the patient and clinic specific variables related to selection and cancellation of cycles, are eliminated.
In summary, it can be very challenging to select the “best” program based purely on pregnancy rates. Ultimately, the best program for a couple will be the one that provides high quality, “state-of-the-art” care, offers a full range of services required to treat the couple both medically and emotionally, is available at convenient times and locations and has physicians and staff that care for the couple in a compassionate and supportive manner.