Prenatal household air pollutant exposure is associated with reduced size and gestational age at birth among a cohort of Ghanaian infants

•Household air pollution exposure during pregnancy affects birth outcomes in Ghana.•Effects are strongest in pregnancies unaffected by placental malaria.•Carbon monoxide during pregnancy is associated with reduced fetal growth.•Carbon monoxide during pregnancy is also associated with shorter gestational age.•Malaria during pregnancy may obscure the effects of air pollution on fetal growth.