We investigated for the first time the association between
small for gestational age and in utero exposure to air pollution in
twins. The associations in the overall group are driven by the twins
born between 32 and 36 weeks. In these twins, the odds of small
for gestational age increased by 68% (95% CI: 27–123) and 51%
(95% CI: 18–95) for each 10 mg/m³ increment in PM10 or NO2 during
the third trimester.