In the secondary analyses, the endometriosis cases with pain with bowel movements had lower levels of TNF-α (GM: 7.18; 95% CI: 6.66–7.73) compared to those without pain with bowel movements (GM: 8.06; 95% CI: 7.41–8.77; p = 0.05; Table S5) when measured using Ella. This evidence concerns the gene TNF and endometriosis.