Problem/Condition: In 1996, CDC initiated data collection regarding assisted reproductive technology (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 includes fertility treatments in which both eggs and sperm are handled in the laboratory (i.e., in vitro fertilization and related procedures). Patients who undergo ART procedures are more likely to deliver multiple-birth infants than women who conceive naturally. Multiple births are associated with increased risk for mothers and infants (e.g., pregnancy complications, premature delivery, low-birthweight infants, and long-term disability among infants).

Reporting Period Covered: 2004.

Description of System: In 2004, CDC contracted with a statistical survey research organization, Westat, Inc., to obtain data from ART medical centers in the United States. Westat, Inc., maintains CDC's web-based data collection system called the National ART Surveillance System.

Results: In 2004, a total of 127,977 ART procedures were reported to CDC. These procedures resulted in 36,760 live-birth deliveries and 49,458 infants. Nationwide, 74% of ART procedures used freshly fertilized embryos from the patient's eggs, 15% used thawed embryos from the patient's eggs, 8% used freshly fertilized embryos from donor eggs, and 4% used thawed embryos from donor eggs. Overall, 42% of ART transfer procedures resulted in a pregnancy, and 34% resulted in a live-birth delivery (delivery of one or more live-born infants). The highest live-birth rates were observed among ART procedures that used freshly fertilized embryos from donor eggs (51%). The highest numbers of ART procedures were performed among residents of California (17,303), New York (11,123), Illinois (9,306), Massachusetts (8,906), and New Jersey (8,513). These five states also reported the highest number of infants conceived through ART. Of 49,458 infants born through ART, 50% were born in multiple-birth deliveries. The multiple-birth risk was highest for women who underwent ART transfer procedures that used freshly fertilized embryos from either donor eggs (40%) or their own eggs (33%). Approximately 1% of U.S. infants born in 2004 were conceived through ART. Those infants accounted for 18% of multiple births nationwide. Approximately 9% of ART singletons, 56% of ART twins, and 95% of ART triplets or higher-order multiples were low birthweight. The percentages of ART infants born preterm were 15% among singletons, 64% among twins, and 98% among triplets or higher-order multiples.

Interpretation: Whether an ART procedure resulted in a pregnancy and live-birth delivery varied according to different patient and treatment factors. ART poses a major risk for multiple births. This risk varied according to the patient's age, the type of ART procedure performed, the number of embryos transferred, the day of embryo transfer (day 3 or day 5), and embryo availability.

Public Health Actions: ART-related multiple births represent a sizable proportion of all multiple births nationwide and in selected states. To minimize the adverse maternal and child health effects that are associated with multiple pregnancies, ongoing efforts to limit the number of embryos transferred in each ART procedure should be continued and strengthened. Adverse maternal and infant outcomes (e.g., low birthweight and preterm delivery) associated with ART treatment choices should be explained fully when counseling patients who are considering ART.