Prenatal diagnosis and multiple pregnancy.

The incidence of twins, triplets, and high-order multiples has increased dramatically in the last two decades secondary to greater reliance on fertility treatments and to delayed childbearing. Offspring of a multiple gestation are at increased risk for both chromosomal and structural abnormalities. Prenatal diagnosis in these patients is challenging. Options for screening tests are limited. Invasive diagnostic procedures are complex. Likewise, physicians and patients may be faced with the dilemma of deciding how to manage discordant results. The following paper will review the unique concerns associated with prenatal diagnosis in a multiple pregnancy and the current methods of prenatal screening in these patients. Invasive prenatal diagnosis will also be explored.