TY - JOUR T1 - P07 Roxithromycin in early pregnancy and the risk of major congenital malformation: a register based nationwide cohort study JF - Archives of Disease in Childhood JO - Arch Dis Child SP - e20 LP - e20 DO - 10.1136/archdischild-2019-esdppp.46 VL - 104 IS - 6 AU - RH Olsen AU - HE Poulsen AU - JT Andersen Y1 - 2019/06/01 UR - http://adc.bmj.com/content/104/6/e20.1.abstract N2 - Background Medicine use during pregnancy often causes concern for fetal harm. Roxithromycin, a macrolide antibiotic, is regarded as inadvisable to use during pregnancy due to lack of safety data. However, alternative macrolides have been associated with adverse outcomes in pregnancy. We conducted a register-based nationwide cohort study testing the hypothesis that use of roxithromycin in the first trimester is associated with major congenital malformations.Methods We included all Danish women giving live birth from 1997 to 2012. Women with at least one redeemed receipt of roxithromycin during first trimester were regarded as exposed. Multivariable logistic regression adjusting for maternal age, multiple birth, parity, year of conception, smoking, educational length, and household income was performed, supplemented by sensitivity analyses comparing unexposed with exposure to increasing accumulated doses of roxithromycin.Results The study included 966,372 pregnancies of which 2,430 children were born to an exposed mother, 78 (3.34%) of the exposed children were diagnosed with a major congenital malformation compared with 33,609 (3.49%) among children born to unexposed mothers. The odds ratio for the occurrence of a major congenital malformation after exposure to roxithromycin was 0.96 (95% CI 0.76–1.20) and multifactorially adjusted 0.94 (0.74–1.18). Sensitivity analyses comparing unexposed with exposure to increasing accumulated doses of roxithromycin showed no dose response relationship. Further, no differences in the type of major malformation according to the EUROCAT subgrouping system were seen.Conclusions We found no association between exposure to roxithromycin in the first trimester of pregnancy and major congenital malformations.Disclosure(s) Nothing to disclose ER -