Results: We identified 23 CpGs (genome-wide p level: 1.06 × 10−7) that were associated with maternal smoking during pregnancy, including associated genes AHRR (cancer development), FTO (obesity), CNTNAP2 (developmental processes), CYP1A1 (detoxification), MYO1G (cell signalling), and FRMD4A (nicotine dependence). Here, AHRR is linked to cancer.