Methods (differential diagnosis, investigations, and treatment):
Tofacitinib was ceased immediately. She and her partner were consulted regarding the potential foeticidal and teratogenic effects of tofacitinib and the lack of human studies on pregnancy outcomes. They decided to continue the pregnancy. She was commenced on folic acid and oral pre-conception multi-vitamin supplement tablets and referred to a high-risk pregnancy clinic. After cessation of tofacitinib, despite being in clinical remission, a follow-up faecal calprotectin had increased to 2,000 ug/g. An unsedated flexible sigmoidoscopy showed Mayo 1 left-sided colitis at eight weeks gestation. Prednisolone 30mg daily was commenced. Due to her previous remission on vedolizumab and the recent introduction of subcutaneous maintenance vedolizumab, she agreed to intravenous induction of 300mg at weeks 0, 2 and 6, followed by subcutaneous vedolizumab 108mg every other week. At eleven weeks of gestation, she remained in clinical remission on prednisolone 20mg daily, and her faecal calprotectin decreased to 62ug/g. First-trimester non-invasive prenatal tests for foetal aneuploidy and nuchal translucency examination were unremarkable. Prednisolone was successfully tapered over two months, and she continued subcutaneous vedolizumab throughout her pregnancy.