Here’s some egg-cellent news for hopeful parents-to-be.
A widely used breast cancer drug could give IVF a boost, with new research showing that adding it to the standard hormone protocol may increase success rates in some difficult-to-treat patients.
The findings come as more Americans than ever are turning to the treatment, in which eggs are fertilized in a lab before being transferred to the uterus in hopes of achieving pregnancy.
But it’s not always a sure bet.
IVF success rates vary significantly. For women under 35, the national average for a live birth after a single embryo transfer hovers between 45% and 55%.
That number drops steadily with age, falling to about 20% to 26% for women between 38 and 40, and roughly 9% to 15% per cycle for those in their early 40s.
Researchers say letrozole, a drug commonly used in breast cancer treatment, may help improve those odds.
In the study, a team of scientists at Dongguan Maternal and Child Healthcare Hospital in China compared IVF outcomes in 176 women between the ages 35 and 42.
All of the participants had diminished ovarian reserve, or a lower-than-expected number of quality eggs in their ovaries for their age.
They were also classified as poor ovarian responders, meaning their bodies didn’t respond well to the hormone drugs used in IVF to stimulate egg production.
The condition is more common in women over 35, as well as those with diminished ovarian reserve.
For this group, simply upping the hormone dose often doesn’t help — it can also drive up costs and side effects.
Finding better ways to stimulate the ovaries in these patients has long been one of the sticking points in reproductive medicine.
Now, there may finally be hope on the horizon.
In the study, researchers split the 176 women into two groups: one received the standard IVF hormone protocol, while the other also got letrozole alongside it.
Letrozole is an aromatase inhibitor, or a drug that blocks the enzyme responsible for converting androgens like testosterone into estrogen.
The medication has already been linked to better pregnancy outcomes in women with polycystic ovary syndrome (PCOS), one of the leading causes of female infertility, by helping induce ovulation.
In the new trial, the benefits extended further. Women in the letrozole group needed less hormone medication and finished ovarian stimulation about two days sooner than those on the standard regimen alone.
They also produced a higher share of mature eggs and more high-quality embryos.
When it came to live births, the difference was striking: 23.7% saw success in the letrozole group compared to 11% in the standard group.
Overall, women taking letrozole were 2.6 times more likely to achieve a live birth.
But age still played a role.
Among women in the letrozole group, those ages 35 to 38 saw a clinical pregnancy rate of 60% and a live birth rate of 44%. That’s compared with just 25.5% and 13.7% in women ages 39 to 42.
“Even though we find that letrozole improves the overall outcomes, younger patients with poor ovarian reserve stand to benefit the most,” the authors wrote.
Looking ahead, the researchers are calling for larger randomized clinical trials across multiple IVF centers to confirm the findings in a broader population.
If the results hold up, the implications could be significant.
With infertility rates rising globally and more women waiting longer to have children, experts say more people are likely to turn to fertility treatments like IVF in the years ahead.
In 2024, more than 100,000 babies were born via IVF in the US for the first time in a single year — a milestone reached through 449,772 reported treatment cycles.
