Monozygotic twinning after assisted reproductive technologies: a case report of asymmetric development and incidence during 19 years in an international group of in vitro fertilization clinics

Objective To describe a case of monozygotic twinning with asymmetric development following a single fresh embryo transfer as part of an intracytoplasmic sperm injection (ICSI) treatment. Secondarily, to report the incidence of monozygotic twinning at the IVI (Instituto Valenciano de Infertilidad) clinics. Design Case report. Setting Private fertility centers. Patient(s) A 33-year-old woman with a 2-year history of primary infertility. Intervention(s) Controlled ovarian hyperstimulation and ICSI treatment with single-embryo transfer. Main Outcome Measure(s) Incidence of monozygotic twinning at the IVI clinics. Result(s) We report a twin pregnancy after a single-embryo transfer. Twins were di…