Increased risk of low birth weight infants is linked to older Latina women but not adolescents, according to a new study.
The finding is a surprise and has potential impact for U.S. health care policy efforts that have focused primarily on adolescent childbearing as the target group for reducing risk, said study director Elena Fuentes-Afflick, M.D., M.P.H., of the University of California, San Francisco.
Previous research has shown that Latina women have higher rates of childbearing during adolescence and over the of age 30 relative to White women, but the risk of maternal age on low birth weight outcomes in Latinas has not been well studied, she said.
Research findings were presented here today (May 16) at the joint meeting of the Pediatric Academic Societies and American Academy of Pediatrics.
The study was based on 1993 California birth certificate information for 220,000 Mexican-origin Latina women. The women were in three general age groups: 20 years and younger, 20 to 24 years, and over 25. The birth weights of their newborns were categorized as very low (under 3.5 pounds), moderately low (3.5 to 5.5 pounds), or normal (5.5 to 9 pounds).
The researchers founds that maternal age influenced the risk of having a low birth weight infant, but only Latina women who were at least 25 years of age had an increased risk. Other factors that were associated with increased risk were the number of previous live births, previous reproductive history, medical complications, and prenatal health insurance.
Fuentes-Afflick is a UCSF assistant professor of pediatrics who treats patients at San Francisco General Hospital Medical Center. Study co-investigator was Nancy Hessol, MSPH, an epidemiologist in the UCSF Department of Medicine. In a related study, Fuentes-Afflick and Hessol looked at the behavioral, medical, and nutritional characteristics of Latina women and how they affect the risk of infant mortality. Their findings were reported in an earlier presentation (May 14) at the joint pediatrics meeting.
The study was prompted by the observation of an "epidemiological paradox" of infant mortality in Latinos that has been documented for nearly 30 years: While Mexican-born Latinas have risk factors associated with infant mortality, they have low rates of infant death. Among the risk factors are less education and higher rates of no insurance, compared to other groups of women.
The underlying mechanism of the paradox is unknown, according to Fuentes-Afflick, but understanding this situation is important for developing educational, medical care, and support programs to maximize positive outcomes in both maternal and child health.
The study was based on 1990-93 California birth certificate information. Data covered 1.5 million births to women who were either Mexican-born Latina, U.S.-born Latina, or U.S.-born White.
The most significant findings were in the areas of behavior and health. Mexican-born women had lower rates of tobacco use and of medical complications compared to the other two groups. This is a partial explanation for the paradox, Fuentes-Afflick said, but more research is needed.
Both studies were funded by UC MEXUS, a University of California research unit that focuses on U.S.-Mexico issues and people of Mexican descent.
Note to the media: The joint meeting of Pediatric Academic Societies and the American Academy of Pediatrics will take place May 12-16 at the Hynes Convention Center in Boston. The Press Room phone is 617-954-2521. For assistance in reaching Dr. Elena Fuentes-Afflick, contact Corinna Kaarlela in the UCSF News Office at 415-476-3804.