This study’s findings constitute the first population-based information on the reproductive health of the entire Hispanic US–Mexico border population. It describes populations that live in close proximity and share a common genetic and cultural heritage but still differ in important ways from one another and from nonborder populations. The differences noted likely reflect various factors, including socioeconomic status, local and national policies, and health care systems.
Trends in total fertility rates on the US side of the border are consistent with economic improvement in the standard of living for US Hispanics during the 2000s and the sharp downturn in income with the recession of the US economy beginning in 2008 (19
). In contrast, total fertility rates in Mexico, which exceeded those of US Hispanics in 2000, have declined rapidly in all populations, with the most likely explanation being the success of Mexican family planning programs (20
General fertility rates among US and Mexican border women were only slightly higher than those of their US and Mexican nonborder counterparts. The largest differences across age groups between border and nonborder regions were among younger women: women younger than 30 in the United States and younger than 25 in Mexico. Birth certificate coverage may be more complete in Mexican border communities, which are more urban and provide greater access to birth facilities than more rural communities elsewhere in Mexico (5
). If true, however, more complete coverage along the border would have increased rates for all age groups and not just those of the youngest women. Therefore, the higher fertility rates along the border are unlikely to be an artifact of better birth certificate coverage.
In the United States, characteristics of nonborder and US births overall were similar, but the prevalence of preterm and early-term births and low birth weight was higher among border births. The cesarean delivery rate was also highest in the US border region at 38%, well above recommendations of 5% to 15% (21
) and well above the US Hispanic rate, which is similar to the rate for all US women (32.9%) (22
). The cesarean rate in Texas border counties (43.5%) and rates in most Mexican areas of at least 40% are of particular note. The Mexican border had fewer preterm, early-term, and low-weight births and more high-weight births than elsewhere in Mexico; cesarean delivery rates in the Mexican border were slightly lower. Low and high birth weight are associated with the development of obesity and diabetes (23
), which are especially prevalent in the border region (2
). Higher rates of late or no prenatal care among US and Mexican border births than births in the interior of either country may reflect border women receiving care on both sides of the border (25
) with resulting disruption in insurance coverage and incompleteness of prenatal records. Fewer prenatal visits among Mexican women may also be influenced by national norms in Mexico that recommend fewer visits for low-risk women (26
) than do guidelines followed in the United States (27
Mothers in US border counties had higher levels of education than other US Hispanic mothers, perhaps reflecting longer residence in the established Hispanic communities of the border region. Mothers in Mexican border municipios
, in contrast, had education levels comparable to Mexico overall, perhaps reflecting migration to the border for jobs in the maquila
industry there (28
). Mothers in the nonborder regions of Mexican border states were better educated, consistent with the lower poverty rates found in nonborder municipios
). The higher percentage of physician-attended deliveries in Mexico than in the United States might be in part an artifact of incomplete reporting of births out of hospital attended by nonphysicians.
State-specific analysis showed that the border populations are not homogeneous. In the United States, Texas border counties and Texas overall had the highest proportions of adverse outcomes. California tended to have better outcomes, but this reflects the affluence of San Diego, which is in the US border region, and contrasts strongly with the less affluent counties to the east. In Mexico, the state of Nuevo Leon had nearly complete receipt of prenatal care, whereas in the state of Baja California coverage was almost as poor as that in US border counties. These interstate differences might be due to differences in income levels, Medicaid coverage (in the United States), or other local health policies.
This is the first study to 1) make use of recently available Mexican birth certificate files, thereby allowing the first comparison of births throughout the border region of the United States and Mexico, 2) compare birth outcomes in individual states within and across the border, and 3) compare Hispanic births in the border and nonborder regions of the border states. Study results may help binational advisory groups and health authorities in the region to identify and implement the best reproductive health practices found on either side of the border.
This study had several limitations. The completeness of Mexican data and the accuracy of some of the birth certificate information are still being assessed. However, at the time of our analysis, we found 3.5% fewer 2009 births estimated to have occurred in Mexico’s border region municipios
) than the 148,820 registered in the birth certificate file (4
). Roughly 95% of births in Mexico now take place in hospitals and clinics (15
); hospitals, clinics, and midwives are all required to submit birth certificates (13
). Misclassification of country of residence in the census and on the birth certificate among undocumented women in the United States and Mexico might affect birth rates, but the direction of the bias is unknown. US states have slowly been implementing the 2003 revision of the birth certificate, and some US registrars or hospitals are still inexperienced with some new topics or revised items in this revision. The US Hispanic population is heterogeneous. Border Hispanics are almost exclusively Mexican, whereas only two-thirds of US Hispanics are of Mexican descent (22
); this factor likely influenced some differences between border states and the United States overall.
In addition, numerous birth certificate variables are only collected in 1 of the 2 countries. For example, Mexico alone collects information on type of hospital and administration of bacillus Calmette-Guerin vaccine, whereas the US alone collects information on maternal morbidity and weight gain during pregnancy. One variable, payment source for delivery, collected in both countries, was not yet available from the US National Vital Statistics System and is not included in this report. Such “asymmetrical” information is not useful in a binational comparison of birth outcomes, but it will be useful in future explorations of reproductive health outcomes and in future attempts to link birth outcomes to adult diseases. For example, information on maternal smoking, prepregnancy body mass index, diabetes, and hypertension could all be exploited in both countries if collected in a standardized way on birth certificates.
This report suggests numerous action steps for public health in the region. Overall priorities on the US side of the border include reducing the numbers of teenage births, preterm and early-term births, low birth weights, cesarean deliveries, and women receiving late or no prenatal care. On the Mexico side, priorities include reducing the numbers of teenage births, cesarean deliveries (which are exceptionally high throughout Mexico), and women receiving late or no prenatal care. Given the heterogeneity of the border population, reproductive health outcomes need to be analyzed not just for the border region as a whole but for the border regions of each state. At least among Hispanics, the border regions are not like the border states or the national Hispanic population, and one state’s border region is not like another’s. Local health departments and community groups can use these data to help set local priorities. Differences in reproductive health outcomes for contiguous US and Mexican border communities might offer clues to factors driving poorer outcomes on one side of the border. Conversely, adjacent border communities with the same reproductive health priorities can collaborate on joint actions to address the needs of a binational population that spends time on both sides of the border (6
Finally, the US–Mexico border regions share a host of other health problems among adults that are related to their shared genetic makeup and behavioral patterns. For example, US Hispanics along the border and their Mexican neighbors both have high rates of obesity, diabetes, and cervical cancer (29
). Future analyses of comparable administrative data sets (eg, mortality data) might reveal the full extent and determinants of these chronic diseases and the factors that contribute to their excess. Sources of such comparable data may already be available, and parallel behavioral risk factor surveys might now be developed. Behavioral surveys currently exist on both sides of the border (30
), but no attempt has been made to improve their comparability. Such standardization could enhance binational collaboration on various health problems across the lifespan.