Women with polycystic ovary syndrome (PCOS) who receive frozen embryos during in vitro fertilization have safer and more successful pregnancies than those who get fresh embryos, according to the results of a recent collaboration between Penn State College of Medicine and Chinese researchers.
PCOS is a hormonal disorder that affects up to 10 percent of women of childbearing age. When women with PCOS undergo in vitro fertilization, they have an increased risk of a dangerous complication called ovarian hyperstimulation syndrome.
Although fresh embryos have been preferred for in vitro fertilization, previous research has suggested that frozen embryos could improve the rate of live births and lower the rates of ovarian hyperstimulation syndrome and pregnancy complications in women with PCOS. In the new study, published in the New England Journal of Medicine, 1,508 infertile women with PCOS were randomized to receive either fresh embryos or frozen embryos during their first in vitro fertilization cycle.
Using frozen embryos lowered the rate of ovarian hyperstimulation syndrome compared to using fresh embryos from 7.1 to 1.3 percent. The group that received frozen embryos also had a higher frequency of live births—due to fewer pregnancy losses—and higher birth weights.
“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,” said Dr. Richard Legro, professor of obstetrics and gynecology and public health sciences at Penn State College of Medicine. “This protocol potentially offers immediate benefits to women with PCOS, so practitioners should consider freezing all embryos for these patients.”