Miscarriage
The data available on miscarriage included 15 studies with 9368 pregnancies. There were 2708 pregnancies in women treated with biologics in pregnancy (Table 2). The proportion of miscarriage in the biologics treated group was 13% (95% CI 0.10 to 0.15), the proportion of miscarriage in the disease matched group was 8% (0.04 to 0.11) and in the disease free group 11% (0.03 to 0.19) (Figure S10). There was no significant difference in proportions between disease matched compared with disease treated women (p=0.078), or in disease free compared with disease treated women comparison (p=0.631; Table S2). One study was excluded from the analysis, they had no difference in their miscarriage rate across their treated and untreated groups of 3%, but a rate much lower than all other included studies20. Subgroup analysis revealed no difference in groups when focusing on anti-TNF-α studies only (results not shown).