BOSTON – A substantial increase in the number of donor oocyte cycles in the United States from 2000 to 2010 was accompanied by an increase in good perinatal outcomes, reported investigators at the conjoint meeting of the International Federation of Fertility Societies and the American Society for Reproductive Medicine.

A review of data from 93% of all fertility centers in the United States showed that the annual number of reproductive cycles using donor rather than autologous oocytes grew from 10,801 in 2000, to 18,306 in 2010.

The trend was accompanied by increases in the proportion of cycles using frozen rather than fresh embryos, as well as elective single-embryo transfer (eSET) vs. multiple transfers, said Dr. Jennifer F. Kawwass, a reproductive endocrinology and infertility fellow at Emory University in Atlanta, and her colleagues. The findings were published simultaneously in JAMA online (2013 [doi:10.1001/jama.2013.280924]).

The data show that single-embryo transfers were associated with a more than twofold improvement in the odds of a good outcome, compared with multiple transfers, and that embryo transfer at day 5 vs. day 3 was associated with a smaller but still significant increase in the chance of a favorable outcome.

Factors associated with lower likelihood of success included tubal- or uterine-factor infertility, and race/ethnicity with non-Hispanic black women having about half the number of successful pregnancies as non-Hispanic white women had.

Societal trends

The findings reflect both societal trends and the evolution of assisted reproductive technologies (ART), commented Dr. William D. Schlaff, Paul and Eloise Bowers Professor and chair of obstetrics and gynecology at Thomas Jefferson University in Philadelphia.

"This shows that people who are doing ART, particularly in the United States, are really putting weight behind the goal of having a single, healthy term pregnancy by transferring a single embryo," he said in an interview.

The data also show that, despite the attendant risks of multiple-fetus pregnancies for mothers and children, some patients may have better outcomes with multiple-embryo transfers.

"If you can identify a subgroup of people with a very good prognosis, particularly if they’re on the fence as to how they would like to proceed, I think you can help them make decisions that would minimize the risk of higher multiples or twins, while not affecting their overall prognosis," Dr. Schlaff said.

The data suggest that oocyte donation is here to stay for the foreseeable future, Dr. Evan R. Myers of the department of obstetrics and gynecology at Duke University in Durham, N.C., noted in a JAMA editorial (2013 [doi:10.1001/jama.2013.280925]).

"More complete data on both short-and long-term outcomes of donation are needed so donors can make truly informed choices and, once those data are available, mechanisms can be put in place to ensure that the donor recruitment and consent process at clinics is conducted according to the highest ethical standards," he wrote.

Dr. Kawwass and her colleagues drew on data reported by fertility centers under mandate to the Centers for Disease Control and Prevention’s National ART Surveillance System. They defined a good perinatal outcome as a singleton born live at 37 weeks’ gestation or later, weighing at least 2,500 g.

Data from the 443 reporting clinics showed the increase in donor oocyte cycles noted before. In addition, the proportion of cycles using frozen embryos increased from 26.7% in 2000 to 40.3% in 2010, and the number of cycles with eSET grew over the same period from just 0.8% to 14.5% (P less than .001 for both trends).

In 2000, 18.5% of cycles resulted in good perinatal outcomes; by 2010, the percentage of good outcomes had improved to 24.4% (P less than .001).

There was no change over time in the mean age of either donors (28 years), or recipients (41 years).

In multivariate analysis controlling for recipient and donor age, race, infertility diagnosis, and number of prior pregnancies, miscarriages, preterm and full-term births and other factors, factors significantly favoring a good outcome were day 5 embryo transfer (adjusted odds ratio 1.17) and eSET (adjusted OR, 2.32).

Conversely, factors negatively associated with good outcomes were tubal-factor infertility (adjusted OR, 0.72), uterine-factor infertility (adjusted OR, 0.74), and non-Hispanic black recipient race/ethnicity (adjusted OR, 0.48).

Sister, can you spare an egg?

In his editorial, Dr. Myers noted that the surveillance data do not include data on health outcomes for oocyte donors.

"Donors are at risk for all of the complications associated with ovulation induction, including the potentially life-threatening ovarian hyperstimulation syndrome. In addition, there is uncertainty about longer-term issues such as effects on the donor’s own fertility or the need to inform recipients about the discovery of health issues not known at the time of donation," he wrote.

The study was supported by the CDC. The authors reported having no conflict of interest disclosures. Dr. Myers disclosed serving as a consultant for AbbVie, Merck, and the CDC, and receiving grants or grants pending from the Patient-Centered Outcomes Research Institute and Hologic-GenProbe.

Oocyte donations in United States rise, with good results