Assisted reproductive technology surveillance -- United States, 2010.

PROBLEM/CONDITION: Since the first U.S. infant conceived with Assisted Reproductive Technology (ART) was born in 1981, both the use of advanced technologies to overcome infertility and the number of fertility clinics providing ART services have increased steadily 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 because more than one embryo might be transferred during a procedure. Multiple births pose substantial risks to both mothers and infants, including pregnancy complications, preterm delivery, and low birthweight infants. This report provides state-specific information on U.S. ART procedures performed in 2010 and compares infant outcomes that occurred in 2010 (resulting from procedures performed in 2009 and 2010) with outcomes for all infants born in the United States in 2010.

REPORTING PERIOD COVERED

DESCRIPTION OF SYSTEM

In 1996, CDC began collecting data on all ART procedures performed in fertility clinics in the United States and U.S. territories, as mandated by the Fertility Clinic Success Rate and Certification Act of 1992 (FCSRCA) (Public Law 102-493). Data are collected through the National ART Surveillance System (NASS), a web-based data collecting system developed by CDC.

RESULTS

In 2010, a total of 147,260 ART procedures performed in 443 U.S. fertility clinics were reported to CDC. These procedures resulted in 47,090 live-birth deliveries and 61,564 infants. The largest numbers of ART procedures were performed among residents of six states: California (18,524), New York (excluding New York City) (14,212), Illinois (10,110), Massachusetts (9,854), New Jersey (8,783), and Texas (8,754). These six states also had the highest number of live-birth deliveries as a result of ART procedures and together accounted for 48.0% of all ART procedures performed, 45.0% of all infants born from ART, and 45.0% of all multiple live-birth deliveries but only 34.0% of all infants born in the United States and U.S. territories. 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 use, was 2,331. In 13 states (California, Connecticut, Delaware, Hawaii, Illinois, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Virginia), this proxy measure was higher than the national rate, and in four states (Connecticut, Massachusetts, New Jersey, and New York) and the District of Columbia, it exceeded twice the national rate. Nationally, among cycles in which at least one embryo was transferred, the average number of embryos transferred increased with increasing age (2.0 among women aged <35 years, 2.4 among women aged 35-40 years, and 3.0 among women aged >40 years). Elective single-embryo transfer (eSET) rates decreased with increasing age (10.0% among women aged <35 years, 3.8% among women aged 35-40 years, and 0.6% among women aged >40 years). ESET rates also varied substantially between states (range: 0 to 45.0% among women aged <35 years). The number of ART births as a percentage of total infants born in the state or territory is considered as another measure of ART use. Overall, ART contributed to 1.5% of U.S. births (range: 0.1% in Guam to 4.8% in Massachusetts) with the highest rates (>3.5% of all infants born) observed in four states (Connecticut, Massachusetts, New Jersey, and New York), and the District of Columbia. The proportion of ART births was ≤2.5% in the remaining states and territories. Infants conceived with ART comprised 20.0% of all multiple-birth infants (range: 0 in Guam to 40.5% in Massachusetts), 19.0% of all twin infants (range: 0 in Guam to 40.0% in Massachusetts), and 33.0% of triplet or higher order infants (range: 0 in several states to 60.0% in Arizona). Among infants conceived with ART, 46.0% were born in multiple deliveries (range: 0 in Guam to 55.4% in Utah), compared with only 3.0% of infants among all births in the general population (range: 1.3% in Guam to 4.7% in Connecticut). A substantial proportion (43.4%) of ART-conceived infants were twin infants, and a smaller proportion (3.0%) were triplets and higher order infants. Nationally, infants conceived with ART comprised 5.6% of all low birthweight (<2,500 grams) infants (range: 0 in Guam to 16.0% in Massachusetts) and 5.6% of all very low birthweight (<1,500 grams) infants (range: 0 in Guam to 15.8% in Massachusetts). Overall, among ART-conceived infants, 31.6% were low birthweight (range: 22.6% in New Hampshire to 48.2% in Puerto Rico), compared with 8.0% among all infants (range: 5.7% in Alaska to 12.6% in Puerto Rico); 5.6% of ART infants were very low birthweight (range: 1.9% in Maine to 14.3% in Montana), compared with 1.4% among all infants (range: 0.9% in Alaska to 2.3% in the District of Columbia). Finally, ART-conceived infants comprised 4.4% of all infants born preterm (<37 weeks; range: 0 in Guam to 13.3% in Massachusetts) and 4.9% of all infants born very preterm (<32 weeks; range: 0 in Guam to 16.2% in Massachusetts). Overall, among infants conceived with ART, 36.6% were born preterm (range: 23.6% in New Hampshire to 56.8% in Wyoming), compared with 12.0% among all infants born in the general population (range: 8.4% in Vermont to 17.9% in Guam); 6.6% of ART infants were born very preterm (range: 0 in Maine to 14.5% in Puerto Rico), compared with 2.0% among all infants born in the general population (range: 1.3% in Alaska to 3.0% in the District of Columbia).

INTERPRETATION

The percentage of infants conceived with ART varied considerably by state and territory (range: 0.1% to 4.8%). In most states, multiples from ART comprised a substantial proportion of all twin, triplet, and higher-order infants born in the state, and the rates of low birthweight and preterm infants were disproportionately higher among ART infants than in the birth population overall. Even among women aged <35 years, for whom single embryo transfers should be considered (particularly in patients with a favorable prognosis) according to American Society of Reproductive Medicine (ASRM) guidelines, on average, two embryos were transferred per cycle in ART procedures, influencing the overall multiple infant rates in the United States. ART use per population unit was distributed disproportionately in the United States, with only 13 states showing ART use above the national rate, which might suggest barriers to ART services in the remaining states. Of the four states (Illinois, Massachusetts, New Jersey, and Rhode Island) with comprehensive statewide-mandated health insurance coverage for ART procedures (e.g., coverage for at least four cycles of IVF), three states (Illinois, Massachusetts, and New Jersey) also had rates of ART use >1.5 times the national level. This type of mandated insurance has been associated with greater use of ART and might account for the differences observed in other states.

PUBLIC HEALTH ACTIONS

Reducing the number of embryos transferred per ART procedure among all age groups and promotion of eSET procedures, when clinically appropriate, is needed to reduce multiple births, including twin births, and related adverse consequences of ART. Improved patient education and counseling on the risks of twins might be useful in reducing twin births because twins account for the majority of multiples. Although ART contributes to increasing rates of multiple births, it does not explain all of the increases, and therefore the possible role of non-ART fertility treatments warrants further study.