|MMWR Surveillance Summaries|
Vol. 66, No. SS-6
February 10, 2017
Assisted Reproductive Technology Surveillance — United States, 2014
Surveillance Summaries / February 10, 2017 / 66(6);1–24
Problem/Condition: 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 the District of Columbia and Puerto Rico) on ART procedures performed in 2014 and compares birth outcomes that occurred in 2014 (resulting from ART procedures performed in 2013 and 2014) with outcomes for all infants born in the United States in 2014.
Period Covered: 2014.
Description of System: 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, and Puerto Rico).
Results: In 2014, a total of 169,568 ART procedures (range: 124 in Wyoming to 21,018 in California) with the intent to transfer at least one embryo were performed in 458 U.S. fertility clinics and reported to CDC. These procedures resulted in 56,028 live-birth deliveries (range: 52 in Wyoming to 7,230 in California) and 68,782 infants born (range: 64 in Wyoming to 8,793 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 2,647 (range: 364 in Puerto Rico to 6,726 in Massachusetts). ART use exceeded the national average in 13 reporting areas (Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Virginia). Eight reporting areas (Connecticut, the District of Columbia, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, and New York) had rates of ART use exceeding 1.5 times the national average.
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 (1.7 among women aged < 35 years, 1.9 among women aged 35–37 years, and 2.3 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 28.5% (range: 4.3% in Puerto Rico to 67.9% in Delaware).
In 2014, ART contributed to 1.6% of all infants born in the United States (range: 0.4% in Puerto Rico to 4.7% in Massachusetts) and 18.3% of all multiple-birth infants (range: 5.5% in Alaska and West Virginia to 37.3% in Hawaii), including 18.0% of all twin infants (range: 5.2% in some states to 36.2% in Hawaii) and 26.4% of all triplets and higher-order infants (range: 0% in some states to 65.2% in Hawaii). Percentages of live births that were multiple-birth deliveries were higher among infants conceived with ART (39.4%; range: 11.5% in Delaware to 55.6% in Puerto Rico) than among all infants born in the total birth population (3.5%; range: 2.2% in Puerto Rico to 4.4% in New Jersey). Approximately 38.0% of ART-conceived infants were twin infants, and 2.0% were triplets and higher-order infants. ART-conceived twins accounted for approximately 95.3% of all ART-conceived infants born in multiple deliveries.
Nationally, infants conceived with ART contributed to 5.5% of all low birthweight (< 2,500 g) infants (range: 1.2% in West Virginia to 14.2% in Massachusetts). Among ART-conceived infants, 27.8% were low birthweight (range: 10.6% in Delaware to 44.4% in Puerto Rico), compared with 8.0% among all infants (range: 5.9% in Alaska to 11.3% in Mississippi).
ART-conceived infants contributed to 4.7% of all preterm (< 37 weeks) infants (range: 1.2% in Puerto Rico to 13.4% in Massachusetts). Percentages of preterm births were higher among infants conceived with ART (33.2%; range: 18.9% in the District of Columbia to 45.9% in Puerto Rico) than among all infants born in the total birth population (11.3%; range: 8.5% in California to 16.0% in Mississippi).
The percentage of ART-conceived infants who were low birthweight was 8.9% (range: 3.2% in some states to 16.1% in Vermont) among singletons and 55.2% (range: 38.5% in Delaware to 77.8% in Alaska) among twins; the corresponding percentages of low birthweight infants among all infants born were 6.3% for singletons (range: 4.6% in Alaska, North Dakota, and Oregon to 9.5% in Puerto Rico) and 55.2% for twins (range: 46.1% in Alaska to 65.6% in Mississippi).
The percentage of ART-conceived infants who were preterm was 13.2% (range: 7.5% in Rhode Island to 23.4% in West Virginia) among singletons and 62.2% (range: 33.3% in some states to 81.4% in Mississippi) among twins; the corresponding percentages of preterm infants among all infants were 9.7% for singletons (range: 1.7% in the District of Columbia to 14.2% in Mississippi) and 56.6% for twins (range: 47.2% in Vermont to 66.9% in Wyoming).
Interpretation: The percentage of infants conceived with ART varied considerably by reporting area. Multiple births from ART contributed to a substantial proportion of all twins, triplets, and higher-order infants born. 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. Compared with ART-conceived singletons, ART-conceived twins were approximately five 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 higher percentages of preterm birth 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 higher than 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), three (Illinois, Massachusetts, and New Jersey) had rates of ART use exceeding 1.5 times the national rate. 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.
Public Health Action: Reducing the number of embryos transferred and increasing use of eSET when clinically appropriate could help reduce multiple births and related adverse health consequences. Because twins account for the majority of ART-conceived multiple births, improved provider practices and patient education and counseling on the maternal and infant health risks of having twins are needed. Although ART contributes to high percentages of multiple births, other factors not investigated in this report (e.g., delayed childbearing and use of non-ART fertility treatments) also contribute to multiple births and warrant further study.