Assisted Reproductive Technology Surveillance - 
United States, 2013

Since the first U.S. infant conceived with assisted reproductive technology (ART) was born in 1981, both the use of ART and the number of fertility clinics providing ART services have increased steadily in the United States. ART includes fertility treatments in which eggs or embryos are handled in the laboratory (i.e., in vitro fertilization [IVF] and related procedures). Women who undergo ART procedures are more likely than women who conceive naturally to deliver multiple-birth infants. Multiple births pose substantial risks to both mothers and infants, including obstetric complications, preterm delivery, and low birthweight infants. This report provides state-specific information for the United States (including Puerto Rico) on ART procedures performed in 2013 and compares infant outcomes that occurred in 2013 (resulting from ART procedures performed in 2012 and 2013) with outcomes for all infants born in the United States in 2013.

2013.

In 1996, CDC began collecting data on ART procedures performed in fertility clinics in the United States 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 collection system developed by CDC. This report includes data from 52 reporting areas (the 50 states, the District of Columbia [DC], and Puerto Rico).

In 2013, a total of 160,521 ART procedures (range: 109 in Wyoming to 20,299 in California) with the intent to transfer at least one embryo were performed in 467 U.S. fertility clinics and were reported to CDC. These procedures resulted in 53,252 live-birth deliveries (range: 47 in Alaska to 6,979 in California) and 66,691 infants (range: 61 in Alaska to 8,649 in California). Nationally, the total number of ART procedures performed per million women of reproductive age (15-44 years), a proxy measure of the ART usage rate, was 2,521 (range: 352 in Puerto Rico to 7,688 in DC). ART use exceeded the national rate in 13 reporting areas (California, Connecticut, Delaware, Hawaii, Illinois, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Virginia, and DC). Nationally, among ART transfer procedures in patients using fresh embryos from their own eggs, the average number of embryos transferred increased with increasing age of the woman (1.8 among women aged <35 years, 2.0 among women aged 35-37 years, and 2.5 among women aged >37 years). Among women aged <35 years, who typically are considered to be good candidates for elective single embryo transfer (eSET) procedures, the national eSET rate was 21.4% (range: 4.0% in Idaho to 77.5% in Delaware). In 2013, ART contributed to 1.6% of all infants born in the United States (range: 0.2% in Puerto Rico to 4.8% in Massachusetts) and 18.7% of all multiple-birth infants (range: 4.5% in Puerto Rico to 35.7% in Massachusetts), including 18.5% of all twin infants (range: 4.5% in Mississippi to 35.3% in Massachusetts) and 25.2% of all triplet and higher-order infants (range: 0% in several reporting areas to 51.5% in New Jersey). Multiple-birth deliveries were higher among infants conceived with ART (41.1%; range: 20.4% in Delaware to 61.6% in Wyoming) than among all infants born in the total birth population (only 3.5%; range: 1.8% in Puerto Rico to 4.5% in Massachusetts and New Jersey). Approximately 39% of ART-conceived infants were twin infants, and 2% were triplet and higher-order infants. ART-conceived twins accounted for approximately 95.4% of all ART-conceived infants born in multiple deliveries. Nationally, infants conceived with ART contributed to 5.8% of all low birthweight (<2,500 grams) infants (range: 0.9% in Puerto Rico to 15.1% in Massachusetts). Among ART-conceived infants, 29.1% were low birthweight (range: 18.3% in Delaware to 42.6% in Louisiana), compared with 8.0% among all infants (range: 5.8% in Alaska to 11.5% in Mississippi). ART-conceived infants contributed to 4.6% of all preterm (<37 weeks) infants (range: 0.6% in Puerto Rico to 13.3% in Massachusetts). Preterm birth rates were higher among infants conceived with ART (33.6%; range: 22.3% in DC to 50.7% in Louisiana) than among all infants born in the total birth population (11.4%; range: 8.8% in California to 16.6% in Mississippi). The percentage of ART-conceived infants who were low birthweight was 9.0% (range: 5.1% in Mississippi to 19.7% in Puerto Rico) among singletons and 56.3% (range: 48.3% in Maine to 72.4% in Puerto Rico) among twins; the corresponding percentages among all infants born were 6.3% for singletons (range: 4.6% in Alaska to 9.6% in Mississippi and Puerto Rico) and 55.3% for twins (range: 43.6% in Alaska to 65.6% in Mississippi). The percentage of ART-conceived infants who were preterm varied from 13.3% (range: 8.7% in Rhode Island to 26.9% in West Virginia) among singletons to 61.0% (range: 47.8% in DC to 78.8% in Oklahoma) among twins; the corresponding percentages among all infants were 10.1% for singletons (range: 6.8% in Vermont to 14.8% in Mississippi) and 56.6% for twins (range: 44.7% in New Hampshire to 68.9% in Louisiana).

The percentage of infants conceived with ART varied considerably by reporting area. In most reporting areas, multiple births from ART contributed to a substantial proportion of all twins, triplets, and higher-order infants born, and the low birthweight and preterm infant birth rates were disproportionately higher among ART-conceived infants than among the overall birth population. Although women aged <35 years are typically considered good candidates for eSET, on average two embryos were transferred per ART procedure with women in this group, increasing the overall multiple-birth rates in the United States. Compared with ART-conceived singletons, ART-conceived twins were approximately four-and-a-half times more likely to be born preterm, and approximately six times more likely to be born with low birthweight. Singleton infants conceived with ART had slightly higher rates of preterm delivery and low birthweight than all singleton infants born in the United States. ART use per population unit was geographically variable, with 13 reporting areas showing ART use above the national rate. Of the four states (Illinois, Massachusetts, New Jersey, and Rhode Island) with comprehensive statewide-mandated health insurance coverage for ART procedures (i.e., coverage for at least four cycles of IVF), two states (Massachusetts and New Jersey) had rates of ART use exceeding twice the national level. This type of mandated insurance has been associated with greater use of ART and likely accounts for some of the difference in per capita ART use observed among states.

Reducing the number of embryos transferred per ART procedure and increasing use of eSET, when clinically appropriate (typically for women aged <35 years), could help reduce multiple births, particularly ART-conceived twin infants, and related adverse consequences of ART. Because twins account for the majority of ART-conceived multiple births, improved patient education and counseling on the maternal and infant health risks of having twins is needed. Although ART contributes to high rates of multiple births, other factors not investigated in this report (e.g., delayed childbearing and non-ART fertility treatments) also contribute to multiple births and warrant further study.