As recently as the early 1980s, twin pregnancy and birth was a relatively rare event, and higher-order multiples were of negligible consequence. However, this did not deter clinicians as well as researchers from evaluating the clinical management of multiples. Obviously, the validity of many of these studies was hampered because of small sample size and underpowered statistics. Beginning in the early 1980s, all we knew about the natural history of multiples has been profoundly changed. Physician-made (iatrogenic) multiple pregnancies are now seen in most developed countries with frequencies approaching 50% in twins and more than 75% in higher-order multiples
