Single Blastocyst Achieves High Conception Rate for Older Women

STANFORD, Calif., Oct. 2 -- Women older than 35 seeking in vitro fertilization may not need multiple embryo transfers to optimize pregnancy, according to investigators here.

More than half of a group of women (mean age 37.3) became pregnant or had successful live-born delivery after single blastocyst transfer, Amin Milki, M.D., of Stanford, and colleagues, reported in the October issue of Fertility and Sterility.

According to the CDC, more than half of all in vitro fertilization cycles using fresh non-donor eggs involve women older than 35. For that age group, the American Society of Reproductive Medicine recommends transfer of two to three embryos to enhance pregnancy rates.

But transfer of multiple embryos increases the likelihood of multiple gestations, the authors noted. Among women older than 35, almost a third of transfers result in multiple gestations. Multiple-gestation pregnancies increase the risks for both the mother and fetus, and those risks are further increased in older mothers, the authors continued.

The benefits of single-blastocyst transfer have been demonstrated previously, but primarily in younger women. Reviewed their experience with single-blastocyst transfer in women older than 35, Dr. Milki and colleagues identified 45 who underwent elective single-blastocyst transfer when multiple blastocysts were available.

About half the women were multiparous, which increases the chances of successful IVF, the authors noted. In 28 of 45 cases (62.2%) successful conceptions occurred. Three conceptions ended in miscarriage. One conception proved to be a biochemical gestation, and one ended in dilatation and evacuation for anencephaly. The remaining 23 successful conceptions translated into a pregnancy rate of 51.1%.

None of the pregnancies resulted in twin gestation. The oldest patient who conceived was 42.9.

"Our experience with elective single blastocyst transfer in women older than 35 has been promising," the authors concluded. "Single embryo transfer is a reasonable option for all good prognosis patients who wish to avoid a multiple gestation pregnancy, regardless of age."

"Although these results represent a selected group of patients, we believe that this preliminary data should serve as encouragement to patients and providers who are considering single blastocyst transfer in the older IVF population," the authors added.