Differences in congenital anomalies in unassisted conception vs. in vitro fertilization in dichorionic-diamniotic twin pregnancies

OBJECTIVE: The aim of this study was to evaluate the incidence of congenital anomalies in dichorionic-diamniotic twins conceived with in vitro fertilization (IVF) vs. unassisted conception pregnancies in a large geographically diverse population. DESIGN: This is a secondary analysis of data from a retrospective cohort study of twin pregnancies seen at 17 centers between December, 2011-February, 2020. SUBJECTS: This study included dichorionic-diamniotic twins conceived unassisted, or by in vitro fertilization. EXPOSURE: The exposure group is dichorionic-diamniotic twins conceived with IVF. MAIN OUTCOME MEASURE: The primary outcome was presence of a congenital anomaly. Neonates with an abnormal newborn examination were evaluated for having a major or minor congenital anomaly and the major anomalies were further classified by organ system (cardiac, renal/genitourinary, gastrointestinal, and musculoskeletal). RESULTS: Of the 968 dichorionic-diamniotic twin pregnancies included, 521 (53.8%) were conceived with IVF and 447 (46.2%) were conceived unassisted. Congenital anomalies were found in 70 pregnancies (7.23%). Of those, 37 were found in pregnancies conceived by IVF (52.9%) vs. 33 unassisted conception pregnancies (47.1). There were no significant differences between IVF and unassisted conception pregnancies for major anomalies or minor anomalies. CONCLUSION: In this large cohort of twin pregnancies, there is no significant difference in the incidence of anomalies for dichorionic-diamniotic twin pregnancies conceived by IVF vs. unassisted conception pregnancies.