Frozen eggs beat IVF for women delaying pregnancy
For women starting a family later in life, frozen eggs are a more efficient option than in vitro fertilization, according to new research.
The study found that 70% of women who froze eggs before the age of 38 and later thawed at least 20 eggs had a child.
The research is based on 15 years of real-world results of frozen egg thawing and the largest US report of elective fertility preservation results to date.
Published in fertility and sterility, the study also found that a significant number of the women studied had more than one child through egg preservation. Overall, the study reports 211 babies who suffered egg freezing.
In comparison, using fresh oocytes or embryos from women who wish to conceive, less than 30% of women undergoing in vitro fertilization (IVF) will become pregnant by the age of 40, and less than 20% will give birth consequently live babies to statistics collected by the Centers for Disease Control and Prevention (CDC) from the nation’s nearly 500 fertility clinics.
Freezing and thawing eggs at a later date offers a higher pregnancy success rate than using fresh embryos during assisted reproductive technology, the researchers say.
More older women give birth
“Our results shed light on the factors that lead to successful births from egg freezing, including careful screening of embryos to be thawed and implanted,” says lead author Sarah Druckenmiller Cascante, associate in the Department of Reproductive Endocrinology and Infertility within the Department of Obstetrics and Gynecology at NYU Langone.
“A better understanding of the live birth rate from egg freezing for age-related fertility decline is needed to inform patient decision-making.”
“Importantly, our study is based on actual clinical experience,” adds Cascante, “rather than mathematical models with limited data, which is most of what has been published about the likelihood of births from oocyte freezing.”
The number of women in the United States who are having children to older ages has been rising for three decades, and there are signs that this trend will continue. According to the US Census Bureau, birth rates have been declining for women in their 20s and skyrocketing for women in their late 30s and early 40s. The median age at first birth has increased from 19 in 1984 to 30 in 2021, and higher in many metropolitan areas.
Women can be their own egg donor
The study involved 543 patients with an average age of 38 years at the time of the first egg freezing, which is older than the optimal age for egg freezing (35 years old or younger). These patients had 800 cycles of oocyte freezing, 605 oocyte thawing and 436 embryo transfers between 2005 and 2020.
The research found that overall 39% of women between the ages of 27 and 44, with a majority between the ages of 35 and 40 at egg freezing, had at least one child from their frozen eggs, which is comparable to age-matched IVF outcomes.
Across all age groups, women who thawed more than 20 mature eggs had a 58% live birth rate, which was profound and unexpected given that this group included people who had passed their reproductive prime. In fact, 14 patients who froze eggs between the ages of 41 and 43 have successfully had children from their frozen eggs.
As previously mentioned, women under the age of 38 with 20 or more thawed mature eggs achieved a 70% live birth rate per patient. Duration of storage of frozen eggs did not change the success rate.
The results also showed that pre-implantation genetic screening with embryos obtained from frozen and finally thawed oocytes resulted in lower miscarriage rates and higher live birth rates per transfer. Such screening also allows for the transfer of single embryos, resulting in singleton pregnancies that are safer for both mother and child, the researchers say.
“Our results provide realistic expectations for those considering oocyte preservation and demonstrate that oocyte freezing technology allows women improved reproductive autonomy,” says senior author James A. Grifo, director of the Division of Reproductive Endocrinology and Infertility and of the fertility center.
“Obum freezing at a young age is becoming an option to be your own egg donor at an advanced age. Because younger patients freeze eggs and complete more than one cycle, success rates will be even higher than reported in this study.”
Grifo, also a professor in the Department of Obstetrics and Gynecology, warns that the study was limited by the number of patients. Future larger studies are underway to expand the dataset that patients can benefit from and model their expected success rates. He adds that additional studies from different geographic locations and center types are also needed.
The Carolyn and Malcom Wiener Foundation provided financial support for the foundational scientific studies that led to NYU Langone’s clinically successful Egg Freezing and Embryo Banking Program.