Maternal prenatal anxiety and stress predict infant illnesses and health complaints.

Evidence from both animals and humans suggests that maternal prenatal anxiety and stress can have adverse consequences on the offspring's development. Animal models also show that prenatal stress has programming effects on the physical health of the offspring, such as immune functioning. In human studies, however, physical health outcomes are often restricted to birth complications; studies on the effects of acquiring illnesses are scarce. This study aimed to examine whether maternal prenatal anxiety and stress, measured both by self-report and by cortisol physiology, are related to more infant illnesses and antibiotic use during the first year of life. Participants in the study were 174 mothers with normal pregnancies and term deliveries (71 firstborns; 91 boys). The mothers filled out third-trimester questionnaires on general and pregnancy-specific anxiety and stress and provided saliva samples for circadian cortisol. Information on infant illnesses and antibiotic use was obtained through monthly maternal interviews across the infant's first year of life. Hierarchical multiple regressions showed that, even after controlling for many relevant confounders, prenatal anxiety and stress predicted a considerable amount of variance in infant illnesses and antibiotic use: 9.3% for respiratory, 10.7% for general, 8.9% for skin, and 7.6% for antibiotic use. Digestive illnesses were not related to prenatal anxiety and stress. Although replication is warranted, to our knowledge, this is the first evidence linking maternal prenatal anxiety and stress to infant illnesses and antibiotic use early in life.