The high rate of teen childbearing among African-Americans is often thought to contribute to the excess black infant mortality rate. A preconceived universal developmental paradigm focuses on maternal age. While the developmental status of teenagers may hinder healthy childbearing, women in their twenties have achieved reproductive and psychological maturity and are thus at lower risk of unhealthy childbearing. Nonetheless, studies have shown that when maternal age is controlled, young maternal age does not have an independent effect on infant mortality. United States national birth and death certificates for 1983 were linked to examine maternal age patterns of neonatal mortality among first births to 15-34 year old white, black, Mexican-American, and Puerto Rican women. The analysis was limited to women of 15-34 years of age since in 1983 only 2.8% of first births occurred to women outside this age.

Across all maternal ages, blacks and Puerto Ricans experienced higher neonatal mortality than their white and Mexican-American counterparts. The white maternal age pattern approximated a reversed-J shaped curve, in which the highest mortality was among teenagers and the lowest mortality was among women 30 to 34. The maternal age pattern for Mexican-American was J-shaped, with the 30 to 34 at higher risk than the teenagers. For blacks and Puerto Ricans, neonatal mortality rate increased as the maternal age increases. Furthermore, as maternal age increased, the black-white and the Puerto Rican-white gaps increased significantly. Mexicans fared better than whites in the teen years and are worse off than whites in the 30-34 maternal age group. Thus, the maternal age patterns of neonatal mortality varied by ethnicity.

The author advanced the Weathering hypothesis to explain why black-white differences in neonatal morality are larger at older than younger maternal ages. The Weathering hypothesis posits that health may deteriorate as an individual ages due to the physical consequence of cumulative socioeconomic deprivation. Although health differences between blacks and whites exist in infancy, childhood, and adolescence, the gap intensifies in young and middle adulthood. The interactions between age and health consequences of environmental hazards and stress due to socioeconomic inequality and racial bias produce adverse maternal health and behavioral characteristics during and before pregnancy that heighten neonatal mortality differentials.

The National Health and Nutritional Examination Survey II data were examined to support her hypothesis. Among black and white women, the prevalence of three risk factors associated with poor pregnancy outcomes – hypertension, blood lead levels, and smoking – were contrasted. During adolescence, there was no difference between the prevalence of hypertension among black and white females. However, at 25 years of age, black women had twice the prevalence and at the end of their reproductive years they had almost four times the prevalence of hypertension of their white counterparts. Similarly, the differential between the proportion of black and white women having blood lead level greater than 15 ug/dl widened among the older compared with the younger age groups. While white adolescent females were more likely to smoke than their black counterparts, by the late 20s, the odds of smoking converged between the two racial groups. However, at older ages, the odds of smoking appeared to be higher for black women than for white women.

Thus, the research findings suggest that the health of black women may deteriorate more rapidly than that of white women. The accelerating health deterioration of African-American women that starts in their twenties may adversely affect their pregnancy outcomes during this time of their life.

In addition the author states that ”it is also possible that while specific maternal health characteristics that are symptomatic of inequality may influence fetal and infant health adversely, the whole of the impact of racial discrimination or other socioeconomic disadvantages on infant outcome may be importantly larger than the sum of its identified maternal health-related part."

In conclusion, the findings contradict the accepted view that reducing early fertility among African-American women will reduce the excess neonatal mortality. Furthermore, the findings raise questions about obstetrical practices that uniformly classify all women in their 20s and early 30s into low risk pregnancy groups. African-American women who give birth for their first time in their 20s and 30s experience neonatal infant mortality rates that are more than twice the rates for white adolescents. Thus, African-American women who postpone their first births to their 20s and early 30s, ages deemed acceptable by the larger American society, may benefit from more careful and guarded consideration by their health care providers.