Prevalence and risk factors of monochorionic diamniotic twinning after assisted reproduction: A six-year experience base on a large cohort of pregnancies.

There is an elevated prevalence of MC-DA twinning after ART. Both maternal age and blastocyst transfer are risk factors of monozygotic pregnancy independently. Blastocyst transfer is a major risk factor of MC-DA twinning in the fresh cycles, while maternal age plays a more important role in the frozen cycles.