Guidelines on Number of Embryos to Transfer

When undergoing in vitro fertilization (IVF), your goal is to have a healthy baby.. The American Society for Reproductive Medicine (ASRM) and Society for Assisted Reproductive Technology (SART) reviewed IVF success rate data to come up with the following embryo transfer guidelines. Fertility doctors are encouraged to follow these guidelines to help you achieve a healthy pregnancy and birth without complications.

Fortunately, there are emerging technologies, like metabolomics, that are making it easier for fertility doctors to determine which embryos are the healthiest ones when choosing which to transfer. It can increase your chance of success and helps mitigate health complications because you can transfer less embryos with peace of mind that they are the most viable ones.

Embryo transfer and health risks
How does embryo transfer affect your risk for complications during pregnancy and birth? If your doctor transfers a larger number of embryos during IVF, you may be more likely to conceive twins, triplets, or more. It is true that many couples raise twins and triplets without serious complications. But multiple gestation comes with a higher risk for complications than pregnancy with a singleton. Because of this, fertility doctors are encouraged to be cautious with the number of embryos transferred during IVF.

What's your IVF prognosis?
Several criteria help your fertility doctor decide on how many embryos to transfer. One of these factors is your prognosis and likelihood of success with IVF. According to the ASRM, the following criteria lead to a more favorable prognosis with IVF:

  • Women going through their first IVF cycle
  • Women with good embryo quality
  • Women with excess embryos available for freezing
  • Women who have been successful with IVF previously

Your doctor factors in your prognosis, your age, and when the embryo is transferred to determine the magic number that you will receive. You will receive a cleavage-stage embryo (2 to 3 days after fertilization) or a blastocyst (5 to 6 days after fertilization).

ASRM embryo transfer guidelines
Here are the ASRM recommendations by age:

  • Under 35: 1 embryo for favorable prognosis/blastocyst transfer; 1 to 2 embryos for favorable prognosis/cleavage-stage transfer; 2 embryos for all others
  • 35 to 37 years: 2 embryos for all patients (except 3 embryos for women with less favorable prognoses who receive cleavage-stage embryos)
  • 38 to 40 years: 2 embryos for favorable prognosis/blastocyst transfer; 4 embryos for less favorable prognosis/cleavage-stage transfer, and 3 embryos for all others
  • 41 to 42 years: 3 embryos for those receiving blastocysts and 5 embryos for those receiving cleavage-stage embryos

The ASRM does not make recommendations for embryo transfer for women over 43. Remember, your doctor may still want to transfer more or less embryos than mentioned above. It is important that your fertility doctor treats you as an individual. Each woman's care may vary.

If cost drives your decision
If you think you can only afford one or two IVF cycles, you may feel pressured to transfer multiple embryos at once. Before begging your doctor for this, discuss your concerns with your fertility doctor. Some studies show that single embryo transfer (SET) may very well help you get pregnant. With the reduced complications associated with multiples, SET may cost less in the long run. Remember, if you become pregnant with multiples, your health and your babies' health could be at higher risk for complications. Multiples may sound fine now, but juggling a job, childcare, housework, pumping, formula, diapers, and more can be even more difficult with long-term health issues.

Before deciding how many cycles you can afford, you may want to consider financial options, such as the Attain® IVF Programs as well as fertility loans to help make treatment more affordable.

Final thoughts on embryo transfer
In conclusion, transferring multiple embryos may slightly increase initial pregnancy rates, but you have to ask yourself, "at what cost?" While multiple gestation does increase the risk of complications to you and your children, millions of women pregnant with multiples do just fine. Consider the increased risk of multiples, and the complications that may occur, and make an informed decision.

Reviewed June 2011 by Dr. Lowell Ku from Dallas IVF.

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