Maria and Teresa Tapia Maria and Teresa Tapia Maria and Teresa Tapia (born April 8, 2010) are formerly conjoined twins born in the Dominican Republic. The twins were joined by their lower chest and abdomen and were therefore classified as omphalopagus sharing a liver, pancreas, and a small portion of their small intestine. On November 7, 2011, the twins underwent a successful separation surgery at the Children's Hospital of Richmond in Virginia. For every 200,000 live births, conjoined twins are born. Conjoined twins are identical and of the same sex one hundred percent of the time and are more common in females than in
Monochorionic twins Monochorionic twins Monochorionic twins are monozygotic (identical) twins that share the same placenta. If the placenta is shared by more than two twins (see multiple birth), these are monochorionic multiples. Monochorionic twins occur in 0.3% of all pregnancies. 75% of monozygotic twin pregnancies are monochorionic; the remaining 25% are "dichorionic diamniotic". If the placenta divides, this takes place after the third day after fertilization. Monochorionic twins generally have two amniotic sacs (called Monochorionic-Diamniotic "MoDi"), but sometimes, in the case of monoamniotic twins (Monochorionic-Monoamniotic "MoMo"), they also share the same amniotic sac. Monoamniotic twins occur when the split takes place after