Maternal-fetal surgery: where are we and how did we get here?

Using the criteria proposed in 1982 to justify consideration of in utero surgical treatment of fetal disorders, the development of maternal-fetal treatment is described, and an assessment of current status is provided. Significant issues remain, and many questions are unanswered. By using three different disorders, congenital diaphragmatic hernia, open spina bifida, and twin-to-twin transfusion, the complexity and sophistication of the field are explored, as well as the existing gaps in understanding.