Objective. Exposure to airborne pollutants during pregnancy appears to be associated with uterine growth restriction and adverse neonatal outcome. Proprotein convertase subtilisin/kexin type (PCSK9) is a key modulator of low-density lipoprotein (LDL) metabolism, and increases following short term particulate matter (PM10) exposure. Because maternal cholesterol is required for fetal growth, PCSK9 levels could be used to evaluate the potential impact of airborne pollutants on fetal growth. Design. A cohort of 134 healthy women during early pregnancy (11–12 weeks of gestational age) was studied. Results. A significant association was found between circulating PCSK9 levels and three tested air pollutants (PM10, PM2.5, nitric oxide (NO2)). Of importance, gestational age at birth was reduced by approximately 1 week for each 100 ng/mL rise in circulating PCSK9 levels. This effect became more significant at the highest quartile of PM2.5 (with a 1.8 week advance in delivery date for every 100 ng/mL rise in circulating PCSK9). This finding was supported by a significant elevation of the odds ratio for urgent cesarean delivery for each 100 ng/mL rise in PCSK9 (2.99, 95% CI, 1.22–6.57), with similar trends being obtained for PM10 and NO2. Conclusions. The association between exposure to air pollutants during pregnancy and elevation in PCSK9 advances our understanding of the unforeseen influences of environmental exposure in terms of pregnancy associated disorders.