IVF experts disagree about whether transferring a fresh or frozen embryo to a patient’s womb offers the best opportunity for healthy babies. According to a study of almost 83,000 IVF patients published in the journal Fertility and Sterility, there is no one-size-fits-all solution. The best technique may vary, depending on how many eggs the patient produces.
For a fresh transfer, patients take hormones for several weeks to stimulate egg production. Doctors retrieve the eggs, fertilize them and place one or more embryos in the mother during the same procedure. But many clinics now universally recommend freezing all embryos and waiting a few weeks for the patient to enter a new menstrual cycle.
According to the study, waiting may be advantageous only for women who produce 15 or more eggs after hormone stimulation. Birth rates for these so-called ‘high responders’ who received frozen embryos were slightly higher (52 percent) than those who received fresh transfers (48 percent).
However, in low and intermediate responders — women who produced 14 eggs or fewer — fresh transfers led to better pregnancy and birth rates compared to those who received frozen embryos.
Further research is needed, said Kelly Acharya, M.D., a fellow in reproductive endocrinology and fertility at Duke and the study’s lead author.
“The bottom line for patients is that they’re likely seeing a lot of information out there saying frozen transfer is best all of the time, and we are seeing that may not be the case. Hopefully, this could put some patients’ minds at ease if they are a low or intermediate responder and doing a fresh transfer.”