The association between TTC delay and increased risk of death was evident among all BC subtypes (hormone receptor positive [HR = 1.46; 95% CI 1.15‐1.84], HER2‐positive [HR = 1.66; 95% CI 1.17‐2.38], and TNBC [HR = 2.18; 95% CI 1.63‐2.91]). This evidence concerns the gene ERBB2 and breast cancer.