Ustekinumab Drug Levels in Maternal and Cord Blood in a Woman With Crohn's Disease Treated Until 33 Weeks of Gestation.

A 35-year old woman with ileocolonic, perianal, and vulval Crohn's disease was treated with subcutaneous ustekinuamb [USK] throughout pregnancy. Dose intervals were shortened from 6-weekly to 4-weekly to maintain clinical remission. The last dose of USK was administered at 33 weeks of gestation, and a healthy baby boy was delivered by caesarean section at 37 weeks. Maternal trough USK levels remained stable during pregnancy. Cord blood USK levels were nearly 2-fold higher than contemporaneous maternal serum levels. To our knowledge, this is the first report of maternal and cord USK levels in a patient with Crohn's disease.