If you're pregnant with twins, you may think that a cesarean section is your only option for delivery. However, this is not always the case, explains Dr. Joseph Garza, an obstetrician/gynecologist and reproductive endocrinologist from the Institute for Women's Health in Texas. Vaginal birth is possible if the twins' heads are down, he states. However, "A C-section should be performed if there is abnormal presentation or in the case of a difficult delivery. Any delay in delivery could decrease oxygen to the unborn twin and cause brain damage," he says.