ROCHESTER, Minn. -- Mayo Clinic researchers have determined a method to achieve the best results for the mother's health and birth of a live baby for women who undergo in vitro fertilization who demonstrate risk of ovarian hyperstimulation syndrome. Embryo transfer into the mother's uterus is delayed after the fertilization of the mother's eggs in the laboratory, and all embryos are frozen until the mother's risk subsides naturally with time. Findings will be presented as an abstract at the American Society for Reproductive Medicine in New Orleans on Tuesday, Oct. 24.
"We take steps to minimize ovarian hyperstimulation syndrome as an issue," says Charles Coddington, M.D., Mayo Clinic reproductive endocrinologist and senior study researcher. "If we feel that there's a good chance a woman would get this syndrome, then we would recommend complete cryopreservation -- freezing -- of her embryos and waiting about a month or so to complete the embryo transfer."
Ovarian hyperstimulation syndrome occurs in approximately 5 percent of women treated with medications to prompt ovulation, the first step in the in vitro fertilization process. A small percentage of those who develop the syndrome (1 to 2 percent) may experience a life-threatening illness. After stimulation, a woman's ovaries can become highly sensitive to hormonal change and start to enlarge, sometimes to orange or grapefruit size, rather than the normal walnut size. Enlargement of ovaries can be painful, as they are surrounded by a tunic that does not allow stretching. The stretched ovaries also secrete fluid into the abdomen, giving the woman a feeling of fullness, which may cause difficulty breathing. Because the fluid has left the vascular system, in a small number of cases, the woman may develop problems with the kidneys or with thrombosis. In extreme cases, blood clots can form in the legs, which can lead to pulmonary embolism.