Why frozen embryos are showing promise.
Polycystic ovary syndrome is a hormonal disorder that affects up to 10 percent of women—sadly, for many PCOS sufferers, getting pregnant is difficult if not impossible, leading them to turn to fertility treatments like IVF. A new study says women with PCOS may benefit from a change to the normal IVF protocol, though, and it could be a game-changer.
A recent collaborative research effort between Penn State College of Medicine and a group of Chinese researchers found that frozen embryos may be a better option for PCOS patients. (This is in comparison to fresh embryos, which are often preferred for IVF implantation.) Why? PCOS patients usually have more risk factors when it comes to IVF: They have a greater likelihood of developing a condition called ovarian hyperstimulation syndrome, which can require additional surgeries or even be fatal. They're also more likely to face complications like miscarriage, preeclampsia, preterm delivery and birth defects. Since the hormones and medications used during IVF can overstimulate the ovaries of PCOS patients, freezing the embryos and implanting them later on might be a gentler option, as it allows a woman's ovaries to recover from all the stimulation and shed the exposed endometrial lining.
The study took place in China, and 1,508 PCOS patients struggling with infertility participated. Members of the group were randomly assigned to either receive fresh or frozen embryos during their first IVF cycles. Women who were implanted with frozen embryos had just a 1.3 percent rate of ovarian hyperstimulation syndrome—much lower than the 7.1 percent rate women who received fresh embryos had. The group that received frozen embryos also had a higher frequency of live births and higher birth weights than the other group.
"Women with PCOS may have a higher chance of a successful pregnancy and may have less ovarian hyperstimulation when you electively freeze all the embryos and perform a frozen embryo transfer than if you do a fresh transfer," Richard Legro, M.D., a professor of obstetrics and gynecology and public health sciences at Penn State College of Medicine, said. "This protocol potentially offers immediate benefits to women with PCOS, so practitioners should consider freezing all embryos for these patients."
"By electing to freeze all the embryos, you create a healthy environment for the best embryos, as opposed to putting them back in a disturbed environment," Dr. Legro continued.
With that being said, there's no clear-cut answer as to which method is better. Frozen embryo transfers are also associated with some negative outcomes—for example, they yield higher rates of preeclampsia and neonatal death, which might be why fresh embryos are generally the preferred route for IVF patients. The researchers maintained that no patients they observed developed severe preeclampsia, though. The rates of neonatal deaths were not significantly different between the groups as well.
According to Dr. Legro, both outcomes need to be studied in greater detail—but for now, there's reason to believe frozen embryos might be a better option for women with PCOS.