PHOENIX, ARIZ. — Pregnancies achieved using donor-egg in vitro fertilization can present a higher risk of pregnancy-induced hypertension than those achieved through standard IVF, according to the results of a retrospective study.
Investigators compared 50 oocyte-donation pregnancies with 50 standard IVF pregnancies at three private practice medical groups at the California Pacific Medical Center in San Francisco. The rate of pregnancy-induced hypertension (PIH) was more than three times higher in the donor-egg IVF group than in the standard IVF group (27% vs. 8%), said Donna Wiggins, M.D., the study's lead investigator and a San Francisco ob.gyn.
PIH was defined as a systolic blood pressure (BP) of at least 140 mm Hg or a diastolic BP of at least 90 mm Hg occurring after 20 weeks' gestation in a woman with previously normal BP.
In looking separately at nulliparous patients, the researchers found greater PIH rates in the donor-egg IVF group (37% vs. 8%), she said at the annual meeting of the Pacific Coast Obstetrical and Gynecological Society.
Among women who had twins, 58% of those in the donor-egg IVF group and 17% of the standard IVF group developed PIH.
The women were between the ages of 30 and 50 years, and the average maternal age in the donor-egg IVF group was 42, compared with 38 in the standard IVF group. But Dr. Wiggins explained that when age stratifications were applied, there was not an increasing incidence with advancing age. And when the multiple logistic regression was applied, age fell out as an indicator of significance with regard to PIH.
Aside from the PIH rates, the two groups showed similar results in most other categories. The cesarean-section rate was 43% in the donor-egg group and 45% in the standard IVF group.
First-trimester bleeding occurred in 12% of the donor-egg group and 14% in standard IVF. And the most common postpartum complications of “lactation difficulties” and postpartum depression occurred in both groups at about the same rate of 10%.
Birthweight was an average of 3,044 g in the donor-egg group and 3,017 g in standard IVF group, and premature labor occurred in the donor-egg group at a rate of 16%, compared with 10% in the standard IVF group.
“In looking at donor-egg and [standard] IVF pregnancies, there aren't that many differences, aside from the significant difference in hypertensive disorders,” said Dr. Wiggins. “All things considered, however, the women for the most part had good outcomes.”
The reasons for the higher PIH rates in donor-egg IVF may have to do with the fact that the donor egg is foreign, Dr. Wiggins speculated. “Unlike any other pregnancy, a donor-egg pregnancy is 100% allogeneic, and this may affect the adequacy of trophoblast invasion and hence hypertensive disorders,” she said at the meeting, cosponsored by the American College of Obstetricians and Gynecologists.
When initially introduced in 1984, donor-egg IVF was primarily indicated for premature ovarian failure, defined as menopause occurring before the age of 40. But the primary indication for egg donation at most IVF centers is now diminished ovarian reserve in women with functioning ovaries, Dr. Wiggins said.