The aim was to evaluate the relationship between maternal corticosteroid use during first trimester of pregnancy and risk of orofacial clefts (OC). The overall findings showed a certain association between maternal corticosteroid use and occurrence of OC, compared with non-users (OR= 1.16 [95% CI: 1.01-1.33]). When study type was considered this association was significant only for case-control studies (OR = 1.22 [95% CI: 1.02-1.47]), and not for cohort studies (OR = 1.09 [95% CI: 0.88-1.34]) when there are many confounders (dose, route of application, disease etc.) and biases (re-call, loss-to followup etc.) that still need to be considered. A subgroup analysis based on the type of OC gave an overall OR of 1.41 (95% CI: 1.14-1.74) in the case-control studies for cleft lip with or without palate (CL/P) and 1.09 (95% CI: 0.80-1.48) for cleft palate only (CPO), when comparing maternal corticosteroid users with non-users. However, for cohort studies, the overall OR for CL/P is 1.06 (95% CI: 0.82-1.37) and 1.20 (95% CI: 0.83-1.75) for CPO. The absolute risk of facial cleft after prenatal exposure to corticosteroids, if any, is small. (C) 2017 Elsevier Inc. All rights reserved.