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 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 two-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.