Abstract
A 31 year-old woman had a single embryo transfer on day 3 after assisted hatching (AH) and intracytoplasmic sperm injection (ICSI) treatment. Ultrasound examination performed 6 weeks after oocyte retrieval revealed a triplet pregnancy combining monochorionic diamniotic twins and a singleton. If zygote splitting resulting in monochorionic triamniotic triplets following IVF has already been described, this case is about an incredibly rare phenomenon after single embryo transfer. Naturally, a concurrent spontaneous conception cannot be excluded. To our knowledge, this is the first time a dichorionic triplet pregnancy after single embryo transfer is reported.