New study confirms Texas Fertility Center research about effects of premature progesterone production in IVF cycles and increasing pregnancy rates with frozen embryo transfer
AUSTIN, TX (September 15, 2017) – A new study published in Fertility and Sterility in August compared the implantation and pregnancy rates in frozen and fresh in vitro fertilization (IVF) transfer cycles. The multicenter matched cohort study examined the contribution of progesterone and maternal age to IVF success.
After comparing the results from the fresh and frozen transfer cohorts, the authors of the study determined that freeze-only transfer protocols produce statistically significantly higher implantation and pregnancy rates compared with fresh cycles, especially when the woman has a progesterone level >1.0 ng/mL at trigger during her IVF cycle. The results remained consistent for women both above and below age 35.
This study has lead researchers to conclude that fertility specialists should shift their embryo transfer protocols from fresh to frozen, confirming the results of research that Texas Fertility Center published two decades ago.
The first to prove the link between progesterone production, FET and IVF success
In 1991, Kaylen Silverberg, M.D., the medical director of Texas Fertility Center, and other experts in the field evaluated the effect of premature progesterone production on pregnancy rates in IVF cycles. They concluded that even minimally increased progesterone production prior to ovulation trigger significantly lowered pregnancy rates. These findings were confirmed by several other studies, however, unlike Silverberg and his colleagues, those authors suggested that progesterone adversely affected the eggs or embryos. In contrast, Silverberg hypothesized that progesterone caused the uterine lining to prematurely mature, while leaving the eggs and embryos unaffected. “Based on earlier animal research, we believed that high progesterone levels had a negative effect on the uterine lining, not the eggs or embryos,” said Dr. Silverberg.
To determine a definitive answer, he and his colleagues then performed a study looking specifically at embryos that were frozen rather than transferred fresh. When they compared pregnancy rates, they found that embryos frozen from cycles with elevated progesterone levels provided the same chance for pregnancy as embryos frozen from cycles with lower progesterone levels. This confirmed their belief that progesterone affected the uterine lining rather than the egg or the embryo. The results of the study, published in 1994, were groundbreaking – rather than continuing the practice of canceling IVF cycles due to premature progesterone production, fertility specialists learned they could simply freeze all of a patient’s embryos for transfer during a later cycle. The reproductive endocrinologists at Texas Fertility Center continued these studies and began performing exclusively frozen embryo transfers several years ago.
Freezing embryos allows fertility specialists to transfer embryos into a woman’s uterus once progesterone levels have dropped and the uterine lining has returned to an optimal condition for implantation. Subsequent studies have shown that babies born from frozen embryo transfer may well be healthier at birth and during the first year of life than babies born from fresh embryo transfer.
Research supports protocols for FET
“The team at Texas Fertility Center is known for performing leading-edge research and incorporating these findings into everyday practice for our patients. Frozen embryo transfers have been an integral part of our IVF practice for decades at Texas Fertility Center, and the new research in Fertility and Sterility confirms our initial research, as well as our shift to frozen embryo transfer protocols,” said Dr. Silverberg.