Background: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous air pollutants generated by combustion of organic material, including fossil fuel. Objectives: It has been an open question whether prenatal exposure to air pollution in general and PAHs in particular significantly increases the risk of intrauterine growth restriction, including small. size for gestational age (SGA), and preterm delivery. Here, we have examined this hypothesis in a cohort of mothers and newborns in New York City. Methods: Subjects were young, nonsmoking, healthy African-American (n = 224) and Dominican (n = 392) mother-newborn pairs residing in New York City whose prenatal PAH exposures were estimated by personal air monitoring. Questionnaire and medical record data were obtained. Results: A 1 natural-log (In)-unit increase in prenatal PAH exposure was associated with a 2-fold increase in risk of symmetric intrauterine growth restriction (i.e., SGA and fetal growth ratio < 85%) among full-term African Americans (p < 0.05). Preterm delivery risk was 5-fold greater among African Americans per In-unit increase in prenatal PAH exposure. The same unit increase in exposure significantly increased the ratio of head circumference to birth weight by 0.04% in African Americans. These effects were not observed in Dominicans. Conclusion: Prenatal PAH exposure is likely to contribute to the occurrence of SGA as well as preterm births among African Americans. The lack of an association in Dominicans might reflect modification of the risk by healthful cultural practices among recent Dominican immigrants. Given that PAHs are globally generated and distributed pollutants, our observations have potential implications for environmental health and energy policies.

Cephalization index Fetal growth ratio Air pollution Small for gestational age Polycyclic aromatic hydrocarbons Symmetric intrauterine growth restriction Ponderal index large for gestational age Preterm birth

head circumference Prenatal Exposure Delayed Effects prenatal exposure intrauterine growth retardation human risk assessment Premature Birth controlled study priority journal African American Dominican Republic Polycyclic Hydrocarbons, Aromatic polycyclic aromatic hydrocarbon United States air monitoring Humans air pollution Adolescent Infant, Newborn female risk factor environmental exposure newborn pregnancy Article Questionnaires adult major clinical study small for date infant New York City prematurity Fetal Growth Retardation Birth Weight environmental health African Americans health survey