Congenital malformations
There were 28 eligible studies in the congenital malformation meta-analysis. There were 1288762 infants in this cohort, (7811 born to women using biologics in pregnancy, 29171 infants born to women with CID who were not treated with biologics in pregnancy and 1251780 infants born to women who were CID free) (Table 1). The proportion of congenital malformations in the treated group was 4% (95% CI 0.03-0.04), the disease matched group was 4% (0.03 to 0.05) and the disease free group 4% (0.03 to 0.05). No differences were observed in proportions between disease matched compared with disease treated women (p=0.238, nor in disease free compared with disease treated women (p=0.579 Figure 1 and Table S1).
Sub analysis by chronic inflammatory disease type did not significantly change results. Those women with IBD treated with biologics had a proportion of congenital malformations of 4% (95% CI 0.02 to 0.05) compared to CID overall having 4% (0.02 to 0.06) and RA alone of 4% (0.02 to 0.05) (Figure S5).