Monozygotic twinning after in vitro fertilization/intracytoplasmic sperm injection treatment is not related to advanced maternal age, intracytoplasmic sperm injection, assisted hatching, or blastocyst transfer

AbstractObjectiveTo evaluate the effect of assisted reproductive techniques on the incidence of monozygotic twins (MZT) and the associated pregnancy outcomes.Materials and methodsThis was a retrospective study of all in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles with MZT pregnancies in our center from January 2001 to December 2011. The diagnosis of MZT pregnancies with their respective placental configurations was based on the results of ultrasonographic examinations performed during either the first or second trimester. The treatment characteristics and outcomes of each IVF cycle were recorded and stored in a computer database.ResultsA total of 17 cycles with MZT pregnancies were identified, resulting in an overall incidence of MZT of 1.3%. The incidence of MZT for women aged