RT Journal Article SR Electronic A1 Parry, Nicola T1 Monozygotic Twinning Risk Increases with Day 5 Embryo Transfer and Assisted Embryo Hatching JF MD Conference Express YR 2014 FD SAGE Publications VO 14 IS 7 SP 17 OP 17 DO 10.1177/155989771407012 UL http://mdc.sagepub.com/content/14/7/17.1.abstract AB This article presents results from an 11-year study showing an increased incidence of monozygotic twin pregnancies over the past decade in association with the use of assisted reproductive technology (ART) [Kanter JR et al. Obstet Gynecol 2014]. Results also showed that Day 5 embryo transfer and assisted embryo hatching are associated with an increased risk of monozygotic twinning.