Monochorionic Twin Pregnancy

A 34-year-old primigravida is referred by her primary care provider to your hospital center’s high-risk obstetrics unit after sonographic imaging confirmed viable intrauterine spontaneous monochorionic diamniotic (MCDA) twins with crown–rump lengths (CRL) of 47 mm and 44 mm, consistent for 12+4 weeks’ gestation by CRL of the larger twin. Twin A’s and twin B’s nuchal translucency (NT) measurements are 1.5 mm and 1.0 mm, respectively, with normal-appearing first-trimester fetal morphologies.