48% were multiple-birth deliveries. The risk for a multiple-birth delivery was highest for women who underwent ART transfer procedures that used fresh embryos from either donor eggs (39%) or their own eggs (31%). Approximately 1% of U.S. infants born in 2006 were conceived through ART. Those infants accounted for 18% of multiple births nationwide. Approximately 9% of ART singletons, 57% of ART twins, and 96% of ART triplets or higher-order multiples were low birthweight. Similarly, 14% of ART singletons, 65% of ART twins, and 97% of ART triplets or higher-order multiples were born preterm. Read more from source: Morbidity and Mortality Weekly Report (CDC) via docuticker