Problem/Condition: Assisted Reproductive Technology (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). This report presents the most recent national data and state-specific results.

Reporting Period Covered: 2006.

Description of System: In 1996, CDC initiated data collection regarding 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]). Beginning with 2004, CDC has contracted with Westat, Inc., a statistical survey research organization, to obtain data from ART medical centers in the United States. Westat, Inc., maintains the National ART Surveillance System (NASS), CDC's web-based data collection system.

Results: In 2006, a total of 138,198 ART procedures were reported to CDC. These procedures resulted in 41,343 live-birth deliveries, and 54,656 infants. ART procedures are categorized into four major procedure types: procedures that used embryos from freshly fertilized eggs (fresh embryos) from the patient's eggs (72%); procedures that used thawed embryos from the patient's eggs (16%); procedures that used fresh embryos from donor eggs (8%); and procedures that used thawed embryos from donor eggs (4%). Overall, 44% of ART transfer procedures resulted in a pregnancy, and 36% in a live-birth delivery (delivery of one or more live-born infants). Live-birth rates were generally higher among ART procedures that used fresh embryos from donor eggs (54%) than among other types. The highest numbers of ART procedures were performed among residents of California (18,886); New York (13,259); Illinois (9,594); New Jersey (9,237); and Massachusetts (8,305). All five states reported the highest number of live-birth deliveries as a result of ART. Of 54,656 infants born through ART, 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.

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 associated with adverse maternal and infant outcomes (e.g., placenta previa, preterm delivery, cesarean delivery, low birthweight, and infant mortality). This risk varied according to the patient's age, the type of ART procedure performed, the number of embryos available for transfer to the uterus, the number transferred, and the day of transfer (day 3 or 5).

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 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 thoroughly when counseling patients considering ART.