Although Mexican-American women tend to have low use of prenatal care services, the prevalence of low birth weight is relatively low compared to non-Hispanic whites. This is more paradoxical considering the disproportionate prenatal risk factors among Mexican-American women. The study examined the effects of prenatal utilization care and maternal risk factors on pregnancy outcomes in Mexican-American and non-Hispanic white women in Arizona. The data were derived from birth certificates containing all live birth certificates for Arizona for 1986 and 1987. The study population consisted of 26,827 Mexican-Americans and 74,379 non-Hispanic whites. The adverse birth outcomes of low birth weight, preterm delivery, and macrosomia (birth weight> 4000g) were evaluated for Mexican-Americans and non-Hispanic whites.

Twenty percent (20%) of Mexican-American women were classified as low maternal risk, in comparison to 31% of white women. With regard to prenatal care utilization, the low risk group in Mexican-Americans and whites had a lower percentage of women receiving inadequate or no prenatal care compared to their high-risk counterparts. Among Mexican-Americans, 13% of the low risk women and 20% of the high risk women received inadequate or no prenatal care. In contrast, 5% of the low risk and 9% of the high-risk white women received inadequate or no prenatal care. Thus, Mexican-American women had at least twice the percentages of mothers in inadequate or no care categories than whites. Maternal risk and level of prenatal care utilization acted independently on pregnancy outcomes of preterm delivery and low birth weight. Among low risk Mexican-American women, the prevalence of low birth weight oscillated only from 3.3 % to 5.3% throughout the various levels of prenatal care utilization and was 4.3% for no care. Among low risk white women it fluctuated from 3.3% for adequate level to 12.3% for no care. Preterm delivery was the greatest adverse birth event among high risk Mexican-American women and low birth weight was the greatest among the high risk white women. Overall, Mexican-born women had a lower prevalence of low birth weight and preterm delivery than US-born Mexican women, regardless of maternal risk or level of prenatal care utilization.

The findings are consistent with previous studies that show that Mexican-American women have a greater proportion of maternal risk factors and lower utilization of prenatal care than non-Hispanic white women. Mexican-Americans had a smaller change in the prevalence of low birth weight across prenatal care utilization levels in both high and low maternal risk categories than the non-Hispanic white women. Mexican values and cultures may positively affect pregnancy outcome regardless of prenatal care utilization. The prevalence of adverse birth outcomes and prenatal care utilization patterns of Mexican-American women differed from those of the non-Hispanic white women. “Prenatal care intervention designed for Mexican-American women should be sensitive to the different cultural factors that are protective against poor pregnancy outcomes in these minority women.”