Adverse pregnancy outcomes in twins and their association with the conception method

Assisted reproductive technology (ART) has given the opportunity of conception to a large proportion of subfertile women and, at the same time, has led to a substantial increase of multiple pregnancies. Several studies have shown that in vitro fertilization conceived twin pregnancies carry a significant risk of perinatal morbidity and complications. However, it remains unknown whether IVF per se actually increases the risk of pregnancy complications in twin pregnancies or if these should be attributed to the maternal characteristics. In the present review we summarize the findings of published studies related to the most common pregnancy complications encountered in IVF conceived twin pregnancies.