Understanding IVF Success Rates
In the United States, all IVF clinics are mandated to report their success rates to the Centers for Disease Control and Prevention (CDC). Additionally, many clinics voluntarily maintain membership in and report to The Society for Assisted Reproductive Technology (SART).
SART maintains rigorous membership standards. Participating clinics must be wholly transparent with their data each year, and these data are subject to thorough auditing, including the review of medical records. Furthermore, member clinics are inspected by a third-party agency every two years to ensure that the clinic and laboratory abide by the highest medical and ethical standards.
As mentioned above, not all fertility clinics report to SART. SART membership ensures complete data reporting and accounts for all patients who start a treatment cycle, even if the cycle is canceled. This presents the most accurate representation of potential success for prospective patients.
IVF success rates are presented in two types of SART Clinical Summary Reports (CSRs). The national CSR displays data from all reporting clinics (allowing patients to see national success rates broken out by category), while clinic-specific reports contain data from just one clinic.
You may notice that the most recent batch of available SART data is labeled “preliminary.” This is because final data is significantly delayed, as conclusive outcomes from some cycles may not be known until up to two years after the cycles began.
The video below demonstrates how to navigate a CSR on SART’s website.
Reading SART statistics, understanding what they mean and determining how they may affect your own potential success can often be confusing and overwhelming. Below we’ve compiled some frequently asked questions about IVF success rates to help you make an informed decision about which fertility clinic you should select for your treatment needs.
Can fertility clinics be compared by their IVF success rates?
Due to vast differences between patient populations in different clinics, as well as differences in patient criteria from one clinic to another, comparing success rates between different clinics is not an accurate indicator of the overall quality and aptitude of a given fertility clinic.
The most accurate indicator of a clinic’s proficiency is live birth rates from fresh donor eggs. This is because most egg donors have been thoroughly screened for fertility, providing a uniform population of fertile patients that may be compared between clinics. However, SART still advises against comparing one clinic’s numbers directly to another’s due to the array of variables in patient population and how each clinic operates.
What should be considered when selecting an IVF clinic?
IVF, like many other medical services, is highly tailored to the individual patient. The clinic you select for this form of fertility treatment should not be chosen solely by comparing the success rates. Success rates are easy to manipulate and clinics will often screen out patients for the purpose of keeping their success rates high. In other words, the rates can be inflated by only treating patients with a good chance of success.
When researching a clinic, it is important to ask what criteria the clinic uses to screen patients. Clinics may have higher success rates only due to accepting and treating patients with a higher chance of becoming pregnant.
Ask the fertility doctor what kind of patients their clinic works with and why. The older and more complex the patient base, the more likely you are to have found a clinic that truly cares about helping their patients have children. These are the clinics that treat the toughest cases, without concern for achieving better “numbers.”
How are IVF success rates calculated and reported?
Live birth rate is the number of babies born divided by the number of cycles started in order to achieve the birth. Remember that this data is usually dated, and patients should keep in mind that doctors are always refining and improving IVF. The success rates represented by SART may be lower than current rates by the time a couple goes through IVF treatment.
Implantation and pregnancy rates on the SART report may be viewed by toggling the “Show Pregnancy Outcomes” button at the foot of each category. This allows readers to see how many patients received a positive pregnancy test, the number of clinical pregnancies (verified by ultrasound), as well as how many ended in miscarriage.
Cycle characteristics on the SART report may be viewed by toggling the “Show Cycle Characteristics” button at the foot of each category. This displays some important data including average (mean) number of embryos transferred and the percentage of patients opting for elective single embryo transfer (eSET).
What are the success rate categories and what do they mean?
The SART report is designed to emphasize the healthiest possible outcome: a singleton pregnancy carried to full term. Unlike previous iterations of the report, it does not emphasize pregnancy rates. Rather, it focuses on the ultimate goal of IVF: a healthy pregnancy and birth resulting from a single embryo transfer.
Following are the success rate categories.
Patient’s own eggs
Data in this category is from patients undergoing IVF using their own eggs (as opposed to donor eggs). This category captures the majority of IVF cycles performed each year, and it is broken down further into the following segments.
- Cumulative outcome per egg retrieval cycle: Overall rate of success for an IVF cycle including all rounds of embryo transfers. The live birth rate reported in this category is called the “cumulative live birth rate,” which signifies the percentage of successful birth outcomes after a year of initiating an IVF cycle.
- Primary outcome: Results from the first embryo transfer.
- Subsequent outcome (frozen cycles): Results from subsequent embryo transfers.
- Live birth per new patient: Success rates for patients who are new to the clinic for the given reporting year.
Donor eggs & embryos
Data in this category is gathered from patients who underwent a round of IVF treatment using donor eggs or embryos. The need for donor eggs and embryos can be due to a variety of potential causes. These include premature ovarian failure, diminished ovarian reserve, age related decline in fertility (typically for patients over 40 years of age), women who have failed multiple rounds of IVF with their own eggs, or preexisting genetic blocks to fertility like inheritable disease.
- Fresh donor eggs: Success rates for patients using fresh (nonfrozen) donor eggs.
- Frozen donor eggs: Success rates for patients using frozen donor eggs.
- Thawed embryos: Success rates for patients using thawed donor embryos that had been frozen.
- Donated embryos: Success rates for all donor embryo cycles.
What is the difference between a fresh cycle and a frozen cycle?
Fresh cycle: The process of extracting a woman’s eggs from her ovaries and inseminating them in the clinic lab under the care of an embryologist. Once the eggs mature into embryos, they are examined so that the best embryo(s) can be transferred to the patient’s uterus. The embryos transferred are the embryos the doctor believes will have the best chance at resulting in a live birth.
Frozen cycle: After a fresh IVF cycle, the lab can freeze any unused embryos. If a second or subsequent rounds of IVF are needed, the embryos can be thawed and transferred. This is called a frozen embryo transfer (FET) cycle, which often yields higher success rates because it eliminates the first steps of the IVF process (ovulation induction and medications, as well as egg retrieval and insemination).