Socially advantaged people are better able to avoid newly identified health risks when biomedical information emerges, and they are positioned to make decisions that lead to longer and healthier lives. Over time this results in the formation of a socioeconomic gradient in health--the unintended consequences of biomedical advances. To gain a better understanding of this process, I consider the role of education, health knowledge and social relationships in decisions about health. I focus on a specific empirical example: prenatal health behaviors among women who are pregnant for the first time (prima gravida women). Over the course of sixteen months, 225 prima gravida women from four clinics participated in in-person survey interviews during their first or second trimesters, and 41 participated in in-depth interviews at the beginning of their third trimesters. The results provide evidence that health knowledge and social network processes mediate the association between education and decisions about health behaviors, but education remains a predictor of health behaviors. This example not only advances our knowledge about the processes that contribute to inequalities in health, it also provides insight into decisions about behaviors that lead to unequal health among women and infants.