http://news.yahoo.com/s/nm/20070309/hl_nm/asians_ivf_dc

NEW YORK (Reuters Health) - In-vitro fertilization (IVF) is apt to be more successful in white women than in Asian women, a study suggests.

Women of Asian descent were 29 percent less likely than their Caucasian counterparts to become pregnant after IVF, Dr. Karen Purcell of Fertility Physicians of Northern California in San Jose and her colleagues found.

Little data is available on how ethnicity affects outcome after infertility treatment, the researchers write in the journal Fertility and Sterility. To investigate, Purcell and her team looked at national U.S. data on 25,843 whites and 1,429 Asians who underwent IVF, as well as more detailed information on 370 white and 197 Asian patients treated at one clinic in San Francisco.

Asian and white women treated at the California clinic were similar in a number of factors that affect IVF outcome, such as the number of eggs retrieved per cycle, age, hormone level, and cause of male infertility. The type of treatment and dosage of hormones the women in both groups received also were similar.

Despite these similarities, the Asian women were 31 percent less likely to become pregnant and 33 percent less likely to deliver a live infant than white women.

In the national data set, results were similar. Asian women were 29 percent less likely to become pregnant and 31 percent less likely to deliver a live infant, and the difference remained significant even after the researchers adjusted for a woman's age and other factors that could affect outcome.

There could be fundamental genetic or biological differences between Asian and white women that affect IVF success, while environmental factors could also be at work, the researchers note.

For example, studies have shown Asian and Pacific Islanders have higher levels of methyl mercury in their blood due to higher seafood consumption, which could be toxic to a developing embryo.

Further study should investigate these issues, the authors say, as well as whether the man's ethnicity and whether or not it is the same as his partner's might be a factor.

"Physicians and patients," the investigators conclude, "need to be aware that infertile Asian women may have more difficulty conceiving than Caucasian women, and appropriate counseling should be made during the treatment course for Asian women."

SOURCE: Fertility and Sterility, February 2007.

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