Understanding IVF success rates doesn’t have to be difficult

Most patients considering in vitro fertilization (IVF) want to know the likelihood that the process will end with a healthy baby. One of the first places many people look for IVF success rates is the Society for Assisted Reproductive Technology (SART), which tracks fertility centers’ success rates with different IVF procedures. Click here to view our Clinic Summary Report on SART.

While SART data reflect each clinic’s track record of success, they cannot predict your personal outcomes from IVF. After all, each patient is unique. As such, our Las Vegas infertility doctors can tell you your approximate chances of success based on your age, diagnosis, procedure and any other relevant factors.

What are the most valuable measures of a center’s success rates?

The most valuable measures of a center’s IVF success rates are its live birth per cycle start and live birth per embryo transfer data. For both these measures, our IVF success rates are consistently higher than the national average, across all age groups.

The data shown below is from the Fertility Clinic Success Rates Report of the Centers for Disease Control, which includes the success rates of The Fertility Center of Las Vegas and the national average.

The above rates count all the following as failures.

• Any patient or couple who produced no eggs or embryos.
• Any patient who had embryos but did not return for an embryo transfer within one year.
• Patients who had an embryo transfer but did not have a live birth.
• Patients using IVF for sex selection, but who had no embryos of their preferred sex.
• Patients who had embryos frozen at one center, but shipped to another center for transfer are counted as failures at the first center even if live birth(s) resulted after embryo transfer at the other center.
• Patients who had embryos frozen and had their first embryo transfer in the subsequent calendar year.  SART instructs that any failed cycles in the subsequent year are counted immediately as failures, but the successful cycles (pregnancies) are deferred until the report is finalized the following year so that birth outcomes can be known.  This causes a negative bias in the success rates because the preliminary reports preferentially include failures but exclude successes until the final version of the report is issued one year later.  This bias is greatest for centers that freeze all embryos, such as the Fertility Center of Las Vegas.

Therefore, the true success rates per patient or per cycle are probably higher than shown.

When viewing per-transfer success rates, keep in mind that these statistics exclude patients who started the IVF process, but never underwent an embryo transfer. This means these figures will be higher than birth rates per cycle start.

What else should you consider when reviewing IVF success rates?

Clinical methods, laboratory equipment, clinician experience and skill, and the patient population can all affect success rates. As a result, when comparing SART data for clinics, be sure that you are comparing “apples to apples.” For example, age is an important factor. As such, success rates for IVF (without donor eggs) in women under 35 are usually higher than those for women over 40.

There are several other important factors to keep in mind when comparing IVF success rates.

• Single vs. multiple embryo transfer. The best centers have high implantation rates, giving them and their patients the confidence to achieve high pregnancy and birth rates with single embryo transfers. Some clinics transfer multiple embryos to boost their success rates, but this practice increases the chance of having a risky twin or triplet pregnancy. For example, in 2017, The Fertility Center of Las Vegas transferred an average of 1.0 embryos in patients under 35 years of age, while the national average was 1.3 embryos per transfer.
• Own eggs vs. donor eggs. Some centers have patients with diminished ovarian reserve move forward using IVF with donor eggs. These clinics may have artificially higher success rates because donor eggs tend to produce higher success rates.

There can also be invisible factors behind the numbers. A failed cycle in SART data could have many causes unrelated to the quality of the fertility center. For example, a failure could occur if a woman doesn’t respond well to medications and her IVF cycle is cancelled. It could also occur if the clinic does not transfer any embryos, due to genetic testing results, or if the patient did not return for thetransfer within one year.

What’s the difference between preliminary and final SART data?

Timing is also a factor. The latest SART data are “preliminary” because they do not include successful frozen embryo transfers in the following calendar year. This system counts failures immediately and defers many successes for one year. The “final” SART reports take one year longer to produce, but are more reliable, especially for clinics like FCLV that only do frozen transfers.

To learn more about our IVF success rates or to schedule a personal consultation with one of our Las Vegas infertility doctors, contact us.