Epigenetic changes, in particular in the placenta, may mediate the effects of prenatal alcohol exposure (PAE) on children’s health. We examined the relationship between PAE patterns, based on dose and timing, and placental global DNA methylation. Using linear regression analysis, we examined the association between different PAE categories and placental global DNA methylation (n = 187), using the proxy measure of Alu-interspersed repeats. Following adjustment for important covariates, we found no evidence of an association between PAE and placental global DNA methylation overall. However, when stratifying by newborn sex, PAE throughout pregnancy was associated with higher placental global DNA methylation (1.5%; p = 0.01) of male newborns. PAE may have sex-specific effects on placental global DNA methylation if alcohol is consumed throughout pregnancy.