Asian-white couples face distinct pregnancy risks, Stanford/Packard

STANFORD, Calif. - Pregnant women who are part of an Asian-whitecouple face an increased risk of gestational diabetes as compared withcouples in which both partners are white, according to a new studyfrom Lucile Packard Children's Hospital and the Stanford UniversitySchool of Medicine.

The researchers also found that Asian women whose partners are whiteare more likely than white women with Asian or white partners to havea caesarean delivery, as part of a broad analysis of perinataloutcomes among Asian, white and Asian-white couples.

The study will be published in the October issue of American Journalof Obstetrics and Gynecology. The findings, the authors say, couldbenefit clinicians working with an increasingly diverse patientpopulation.

"There's great heterogeneity in our country; there are people of manydifferent races and backgrounds," said co-author Yasser El-Sayed, MD,a Packard Children's Hospital obstetrician and associate professor ofobstetrics and gynecology at the medical school. "Gaining betterinsight into the risks facing specific populations provides for bettercounseling and better prenatal care."

It's difficult to estimate the prevalence of Asian-white couples, but14.3 percent of Americans reporting Asian race in the U.S. CensusBureau's 2000 survey also reported being of mixed Asian-whiteancestry. Although past studies have looked at ethnic differences inperinatal outcomes, the majority of research has focused on white-African-American couples. Few studies have focused specifically onAsian-white couples, said El-Sayed, who is also associate chief ofmaternal-fetal medicine.

To learn more about outcomes and risks in this population, theresearchers looked at data from white, Asian and Asian-white coupleswho delivered at the Johnson Center for Pregnancy and Newborn Servicesat Packard Children's from 2000 through 2005. (During that timeperiod, 5,575 white, 3,226 Asian and 868 Asian-white couples deliveredbabies at the hospital.) The team recorded the type of delivery -caesarean vs. vaginal - and examined perinatal outcomes includinggestational diabetes, hypertensive disorders of pregnancy, pretermdelivery and birth weight.

El-Sayed and his colleagues found, as noted in their paper, that Asian-white couples "represent a population with distinct perinatal risksthat differ depending upon which parent is of Asian race."

More specifically, the researchers found that white mother/Asianfather couples had the lowest rate (23 percent) of caesarean delivery,while Asian mother/white father couples had the highest rate (33.2percent). Because birth weights between these two groups were similar,the researchers say the findings suggest that the average Asianwoman's pelvis may be smaller than the average white woman's and lessable to accommodate babies of a certain size. (Asian couples hadbabies with the lowest median birth weight, so caesarean delivery wasless common among those women.)

It's important for clinicians to know which women may have anincreased risk of caesarean delivery, so they can conduct propercounseling prior to childbirth, El-Sayed said.

El-Sayed and his colleagues also found that the incidence ofgestational diabetes was lowest among white couples at 1.61 percentand highest among Asian couples at 5.73 percent - and just under 4percent for Asian-white couples. These findings weren't altogethersurprising: past studies have shown an increased risk of diabetesamong Asian couples, which researchers attribute to an underlyinggenetic predisposition. But the interesting finding, El-Sayed said,was that the risk for interracial couples was about the sameregardless of which parent was Asian.

Based on their findings, El-Sayed said clinicians should consider bothmaternal and paternal race when determining a patient's risk forperinatal complications. "One has to factor in as many relevantvariables as possible when you counsel a patient about pregnancy," hesaid. "We've shown in this paper that if you have an interracialcouple, depending on which parent is of which race, there may bedifferent relative risks of certain outcomes that could inform andenhance clinical management."

Noting the growing number of interracial couples in the San FranciscoBay Area and beyond, El-Sayed said he expects to see more outcomesresearch like this in the future. "These kinds of studies will becomeincreasingly common," he said.

Source: Stanford University Medical Center