Fetal Protection

Caitlyn D. Placek, Edward H. Hagen

Pregnancy involves puzzling aversions to nutritious foods. Although studies generally support the hypotheses that such aversions are evolved mechanisms to protect the fetus from toxins and/or pathogens, other factors, such as resource scarcity and psychological distress, have not been investigated as often. In addition, many studies have focused on populations with high-quality diets and low infectious disease burden, conditions that diverge from the putative evolutionary environment favoring fetal protection mechanisms. This study tests the fetal protection, resource scarcity, and psychological distress hypotheses of food aversions in a resource-constrained population with high infectious disease burden. The role of culture is also explored. In the first of two studies in Tamil Nadu, India, we investigated cultural explanations of pregnancy diet among non-pregnant women (N = 54). In the second study, we conducted structured interviews with pregnant women (N = 94) to determine their cravings and aversions, resource scarcity, indices of pathogen exposure, immune activation, psychological distress, and emic causes of aversions. Study 1 found that fruits were the most commonly reported food that pregnant women should avoid because of their harmful effects on infants. Study 2 found modest support for the fetal protection hypothesis for food aversions. It also found that pregnant women most commonly avoided fruits as well as "black" and "hot" foods. Aversions were primarily acquired through learning and focused on protecting the infant from harm. Our findings provide modest support for the fetal protection hypothesis and surprisingly strong support for the influence of cultural norms and learning on dietary aversions in pregnancy.