Problem/Condition: Since the birth of the first U.S. infant conceived with Assisted Reproductive Technology (ART) in 1981, use of advanced technologies to overcome the problem of infertility has increased steadily, as has the number of fertility clinics providing ART services in the United States. ART includes fertility treatments in which both eggs and sperm are handled in the laboratory (i.e., in vitro fertilization [IVF] and related procedures). Women who undergo ART procedures are more likely to deliver multiple-birth infants than those who conceive naturally. Multiple births pose substantial risks to both mothers and infants, including pregnancy complications, preterm delivery, and low birthweight infants. This report presents the most recent data on ART use and birth outcomes for U.S. states and territories. Reporting Period Covered: 2009. Description of System: In 1996, CDC began collecting data on all ART procedures performed in the United States, as mandated by the Fertility Clinic Success Rate and Certification Act of 1992 (FCSRCA) (Public Law 102-493 [October 24, 1992]). ART data for 1995-2003 were obtained from the Society of Assisted Reproductive Technology (SART) through its proprietary Clinical Outcomes Reporting System data base (SART CORS). Since 2004, CDC has contracted with Westat, Inc., a statistical survey research organization, to obtain data from fertility clinics in the United States through the National ART Surveillance System (NASS), a web-based data collection system developed by CDC. Results: In 2009, a total of 146,244 ART procedures were reported to CDC. These procedures resulted in 45,870 live-birth deliveries and 60,190 infants. The largest numbers of ART procedures were performed among residents of California (18,405), New York (14,539), Illinois (10,192), Massachusetts (9,845), New Jersey (9,146), and Texas (8,244). Together, these six states reported the highest number of live-birth deliveries as a result of ART and accounted for 48% of all ART procedures initiated, 46% of all infants born from ART, and 45% of all ART multiple-birth deliveries but only 34% of all births in the United States. Nationally, the average number of ART procedures performed per 1 million women of reproductive age (15-44 years), which is a proxy indicator of ART utilization, was 2,361. In four states (Massachusetts, New York, New Jersey, and Connecticut) and the District of Columbia, this proxy measure of ART use exceeded twice the national average. Nationally, the average number of embryos transferred was 2.1 among women aged 35 years, 2.5 among women aged 35-40 years, and 3.0 among women aged 40 years (and varied most in this age group from 1.7 in Maine to 3.5 in Missouri). Age-specific elective single-embryo transfer (eSET) rates were approximately 7% among women aged 35 years, 3% among women aged 35-40 years, and 0.5% among women aged 40 years. The highest rates of eSET were observed among women aged 35 years (41% in Delaware, 20% in Iowa, and 17% Massachusetts). Overall, ART contributed to 1.4% of U.S. births (ranging from 0.2% in Puerto Rico to 4.3 % in Massachusetts). The proportion of ART to total infants born in the state or territory, which is another measure of ART utilization, was highest in Massachusetts (4%) with high rates also observed in New Jersey, New York, Connecticut, and the District of Columbia (>3% of all infants born). Infants conceived with ART accounted for 20% of all multiple-birth infants (ranging from 4% in Maine to 41% in New York), 19% of all twin births (ranging from 4% in Maine to 42% in New York) and 34% of triplet or higher order births (ranging from 0 in several states to 61.5% in New Jersey). Among infants conceived with ART, 47% were born as multiple-birth infants (ranging from 35% in Delaware to 60.8% in Wyoming), compared with only 3% of infants among the general birth population (ranging from 1% in New York to 5% in Connecticut).