Cervical cancer incidence and mortality rates are higher among women in Mexico (29.5 per 100,000 and 14.1 per 100,000, respectively) than among Hispanic women in the United States (12.2 per 100,000 and 3.1 per 100,000) (1-3). Cervical cancer remains the leading cause of cancer deaths among women in Mexico, accounting for 16.5% of all cancer deaths among women, compared with 2.4% in the United States (4).

In the United States, the successful implementation of the Papanicolaou (Pap) test to screen for precursor lesions has reduced both the incidence of and mortality from cervical cancer in the last 50 years (5,6). Despite the initiation of a national cervical cancer screening program in Mexico in 1974, screening rates vary from 15% in very rural areas to 64% in urban areas (7-9). Two previous studies using binational samples found that US residence was associated with increased odds of cervical cancer screening (10,11). Both studies, however, had low participation rates and were limited to women aged 40 years or older. In Healthy Border 2010, the United States-Mexico Border Health Commission set goals for a 20% reduction in cervical cancer mortality for the Mexico border population and a 30% reduction in cervical cancer mortality for the US border population (12). To achieve this goal, Pap testing coupled with appropriate follow-up of abnormal Pap tests must increase on both sides of the border.

In countries with no organized screening programs, prenatal care offers an opportunity for women who typically have minimal contact with a health care provider to get a Pap test at least once in their lifetime. We compared the prevalence of lifetime cervical cancer screening and identified predictive factors among women on each side of the US-Mexico border who recently gave birth.

The weighted prevalence of ever having had a Pap test was 62.1% among women who lived in Matamoros, compared with 95.7% among women who lived in Cameron County. The weighted prevalence of having had a Pap test in the previous 3 years was similar at 58.0% and 94.8%, respectively (Table 1).

Women primarily delivered in their country of residence. Nearly all Matamoros residents completed the interview in Spanish, compared with a nearly even distribution between respondents who completed the interview in Spanish or English in Cameron County. Of the total sample, 5% of respondents had an ethnicity other than Hispanic (Table 1).

Women who lived in Matamoros but delivered in the United States were more likely to have had a Pap test (88.8%) compared with women who lived in Matamoros and delivered in Mexico (60.7%) (Table 2). In the overall border region, 95.6% of women who delivered in the United States reported having had a Pap test compared with 60.6% of the women who delivered in Mexico. Increasing age was consistently associated with increased likelihood of having had a Pap test.

Maternal birthplace in Mexico was associated with a lower likelihood of ever having had a Pap test among residents of  Cameron County and the overall border region. In Cameron County, the prevalence of ever having had a Pap test among women born in Mexico was approximately 5 percentage points lower than that among women born in the United States. This disparity was nearly 30 percentage points in the overall border region.

Women with higher levels of education (≥12 years) in each county and overall were more likely to have had a Pap test. In Matamoros and the overall border region, increasing gravidity was associated with an increase in the prevalence of ever having had a Pap test. Differences between primigravid women and women with 5 or more pregnancies were among the largest of any reported.

In Cameron County and the overall border region, women who received any prenatal care were more likely to have had a Pap test compared with women who had no prenatal care. In Cameron County, the prevalence of ever having had a Pap test exceeded 95% among women receiving prenatal care but was 32.7% among women who received no prenatal care. In the overall border region, a similar pattern was observed.

In Matamoros and the overall border region, respondents with 4 or 5 healthy behaviors had higher rates of ever having had a Pap test. In Matamoros, the prevalence of ever having had a Pap test was approximately 18 percentage points higher for women with 4 to 5 healthy behaviors than for women with fewer healthy behaviors. In the overall border region, the difference between these groups was slightly greater, approximately 22 percentage points.

This study identifies a large disparity in Pap testing between women who delivered in Matamoros and those who delivered in Cameron County and suggests that prenatal care is a valuable opportunity to increase Pap test coverage. Rates of Pap testing in Matamoros were similar to rates reported in other Mexican studies (1,14,15). Conversely, in Cameron County, the rates reported in this study exceeded previously reported overall rates in Texas and rates specific to the Texas-Mexico border, most likely because the Cameron County women in our survey had just delivered and almost three-quarters of them had had a Pap test during prenatal visits (16,17).

Pap testing has been a routine part of prenatal care in the United States since the early 1980s (18). Interaction with a health care provider during pregnancy may present an opportunity for increased use of preventive services, including cervical cancer screening and referral. By focusing on women who recently delivered a live infant, this study explores cervical cancer screening in a subgroup in which the lifetime screening prevalence is expected to be much higher. Previous studies have found lifetime Pap test screening to be a cost-effective method to reduce disease burden, especially in resource-limited settings (19-21). These data suggest that an opportunity to increase lifetime Pap test prevalence is being missed in Matamoros.

Whether prenatal care represents the best opportunity to increase Pap testing is a source of controversy. Nygård et al recently evaluated the role of prenatal care in improving Pap test rates in Norway (22). They concluded that this strategy needs to consider country-specific factors such as the age at which the incidence of precancerous lesions peaks, the age at which human papillomavirus (HPV) prevalence peaks, the mean age of pregnancy, the accuracy of the prenatal Pap test to diagnose underlying preinvasive lesions, and the impact this strategy may have on coverage compared with other strategies (22).

Whether cervical cancer screening needs to be cytology-based is another heavily debated topic in Latin America. Cytology-based screening presents challenges in resource-limited settings, but recent research has suggested that DNA testing for HPV, which uses an assay system, can improve access to cervical cancer screening in resource-limited settings and, because the specimen can be self-collected, this type of test may reduce the patient anxiety and apprehension sometimes associated with Pap testing. However, HPV DNA testing is expensive. On the other hand, visual inspection with acetic acid (VIA) is more affordable for a developing country and is considered more accurate than Pap tests (23,24). Although VIA may yield some false-positives and lead to overtreatment, VIA offers an immediate result, so treatment can be initiated right away.

Age and gravidity were positively associated with Pap testing. These findings are expected when considering the cervical cancer screening guidance in each country. In Mexico, routine cervical cancer screening begins at age 25 and should be conducted every 3 years (1). In the United States, most guidelines recommend that a Pap test should begin within 3 years after initiating sexual activity or by age 21, whichever is earlier (25,26). The most cost-effective strategies to reduce the burden of cervical cancer in low-resource settings is to offer 1 or 2 screenings starting at age 35 (21). A recent economic analysis in Mexico concluded that HPV vaccination (when affordable vaccine is available) at age 12 and a combination of Pap and HPV screening for women aged 25 to 64 years may be more beneficial than Pap testing alone (27).

Our findings demonstrate a need for binational collaboration to support healthy behaviors. Women in this study who practiced several healthy behaviors had higher screening rates. This finding suggests that a coordinated binational campaign supporting healthy behaviors would not only reduce preventable illness and death but also could influence cervical cancer screening rates.

Hispanic women in Cameron County were more likely to have had a Pap test compared with non-Hispanic women. This finding is in contrast to previous studies that consistently reported a lower prevalence of cervical cancer screening among Hispanic women, especially among Mexican-origin Hispanic women (16,28-30). There are several possible explanations for this finding. Barriers to cervical cancer screening are perceived pain, lack of knowledge of the test, and not knowing where to go (16,28,29). In at least 1 study, Hispanic women cited physician sex and insensitivity to patient needs as barriers to cervical cancer screening (28). With increasing numbers of women in obstetric practice (31-33), this barrier may not be as significant in the prenatal population and may contribute to the increased prevalence of lifetime Pap testing in this study population. Another possible explanation is that the ethnic concentration of Hispanic women in Cameron County, 88.9%, provides increased social support and reduced barriers. Further research is needed to confirm and examine possible causes for this finding.

Failure to screen for cervical cancer increases the likelihood of late-stage diagnosis, the risk of mortality, and health care costs. In Mexico, despite the availability of cervical cancer screening for more than 35 years, less than 13% of preventable cases have been averted (4). Women who participate in prenatal care have increased interaction with the health care system. This increase in interaction presents an opportunity to increase lifetime cervical cancer screening prevalence by ensuring that all women receive screening during prenatal care. Increased efforts may be needed to discuss with Mexico's policy makers, physicians, and public health community whether prenatal care is the best opportunity to increase lifetime Pap testing prevalence and help to achieve the Healthy Border 2010 goal of a 20% reduction in cancer mortality (12).

The BMSCP was funded through the Division of Reproductive Health and the Office of Global Health Promotion at the National Center for Chronic Disease Prevention and Health Promotion, CDC, under a cooperative agreement with the United States-Mexico Border Health Association, No. U65 CCU 623699-01-2, and through interagency personnel agreements with the University of Texas at Brownsville, Texas Southmost College, and the University of Texas-Houston School of Public Health, Brownsville Regional Campus. In-kind project support was provided by the Division of Health Examination Statistics at the National Center for Health Statistics, CDC; the Texas Department of State Health Services, Region 11; the Secretariat of Health, Tamaulipas; and the Mexican Institute of Social Security, Tamaulipas.

Support from the following local, regional, and national institutions was critical to the project: the National Center for Gender Equity and Reproductive Health, Mexican Health Secretariat; National Center for Epidemiologic Surveillance and Disease Control, Mexican Health Secretariat; National Center for Health Promotion, Mexican Health Secretariat; National Institute of Statistics, Geography and Informatics, Tamaulipas; Civil Registry, Tamaulipas; Institute for Social Security and Services for State Workers, Tamaulipas; Secretariat of Health, Jurisdiction III, Tamaulipas; Texas Department of State Health Services, Region 11 and Office of Border Health; City of Brownsville Department of Public Health; Cameron County Health Department; Valley Baptist Medical Center in Harlingen; Valley Baptist Medical Center in Brownsville; Valley Regional Medical Center; Harlingen Medical Center; Cameron Park Cultural Center; Brownsville Community Health Center; General Hospital of Matamoros; Dr. Alfredo Pumarejo Lafaurie; Mexican Institute of Social Security General Hospital, Zone #13, Matamoros; Dr Manuel F. Rodríguez Brayda Clinical Hospital, Matamoros; Hospital Guadalupe; Matamoros Center of Family Orientation; Medical Center of Surgical Specialties of Matamoros, and the United States-Mexico Border Health Commission. We thank the National Center for Gender Equity and Reproductive Health, Secretariat of Health, Mexico, for review of this manuscript and the United States-Mexico Border Health Commission for providing the English-to-Spanish translation.