State-Specific Assisted Reproductive Technology Surveillance, United States: 2019 Data Brief
2019 Data Brief
Since the birth of the first US infant conceived with assisted reproductive technology (ART) in 1981, both the use of ART and the number of fertility clinics providing ART services have increased steadily (1, 2). ART includes fertility treatments in which eggs or embryos are handled in the laboratory (i.e., in vitro fertilization [IVF] and related procedures) (1). Although the majority of infants conceived through ART are singletons, women who undergo ART procedures are more likely than women who conceive naturally to have multiple births because multiple embryos may be transferred (3). Multiple births can pose substantial risks for both mothers and infants, including obstetric complications, preterm birth, and low birthweight (4-7). This report provides state-specific information on US ART procedures performed in 2019 and compares birth outcomes that occurred in 2019 with outcomes for all infants born in the United States in 2019 and includes data from the 50 states, the District of Columbia, and Puerto Rico.
Data for ART procedures and ART birth outcomes were obtained from CDC’s National ART Surveillance System (NASS) for reporting years 2018 and 2019 (1,8). See Technical Notes for more information about NASS and the data collected through that system. Data for all infants born in the United States were obtained from CDC’s National Vital Statistics System for reporting year 2019 (9,10). To compare ART births to all US births in 2019, ART-conceived births were aggregated from procedures performed in 2018 and 2019. The data are presented nationally and for 50 States, District of Columbia, and Puerto Rico, classified by mother’s reported state of residence at time of treatment. This report presents data on all procedures initiated with the intent to transfer at least one embryo, including procedures that used thawed embryos for transfer. All cycles in which egg or embryo banking was performed for future ART cycles were excluded.
We first calculated the number and outcomes of ART procedures performed in 2019 and the number of ART procedures performed per million women 15-44 years of age using data on population size from the US Census Bureau (11). Because patients can undergo multiple ART procedures, measures of ART use are an approximation; certain women who use ART are younger or older than the age range of 15–44 years, and certain women might have had more than one procedure during the reporting period. Average number of embryos that were transferred and the proportion of embryo-transfer procedures performed with a single embryo in 2019 were calculated for women <35 years, 35-37 years, and >37 years. The number of infants born in 2019 that were singletons, multiples (twins, triplets and higher order), with low birthweight (<2,500g), or preterm (<37 weeks gestation) was calculated for ART infants and all infants, as well as the respective percentages for each group. The proportion of ART infants among all infants with these outcomes was also calculated. The proportion of ART-conceived infants among all US births that were low birthweight or preterm as well as the proportion of small for gestational age (born at <10th percentile of birthweight for gestational age) infants were calculated for singleton births.
In 2019, there were 209,687 ART procedures (range: 149 in Alaska to 26,090 in California) performed in 448 US fertility clinics and reported to CDC (Table 1 and Figure 1). These procedures resulted in 77,998 live birth deliveries (range: 62 in Alaska to 10,037 in California) and 83,946 infants (range: 67 in Alaska to 10,820 in California) born. Nationally, 3,226 ART procedures were performed per million women of reproductive age (15–44 years). ART use rates exceeded the national rate in 16 states (California, Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Utah, Vermont, and Virginia). ART use exceeded 1.5 times the national rate in 8 states (Connecticut, Delaware, the District of Columbia, Illinois, Maryland, Massachusetts, New Jersey, and New York).
Nationally, among all ART transfer procedures, the average number of embryos transferred was similar across age groups (1.2 among women aged <35 years, 1.2 among women aged 35–37 years, and 1.3 among women aged >37 years) (Table 2). Single-embryo transfer (SET) rates among all embryo-transfer procedures were 80.6% among women aged <35 years (range: 40.5% in Puerto Rico to 94.4% in the District of Columbia), 79.5% among women aged 35-37 years (range: 29.5% in Puerto Rico to 91.5% in Delaware), and 72.4% among women aged >37 years (range: 40.4% in Puerto Rico to 85.2% in Delaware).
In 2019, ART contributed to 2.1% of all infants born in the United States (range: 0.5% in Puerto Rico to 5.5% in Massachusetts) (Table 3). Approximately 83% of ART-conceived infants were singleton infants. Approximately 16.3% (12,798 of 78,525) of ART-conceived infants were twins and 0.5% (395 of 78,525) were triplets and higher-order infants. Overall, ART contributed to 10.6% of all multiple births, including 10.6% of all twin births and 12.0% of all triplets and higher-order births (Table 4). Almost all (97.0%) of ART-conceived multiple births were twins. The percentage of multiple births was higher among infants conceived with ART (16.8%) (range: 8.6% in Delaware to 37.3% in North Dakota) than among all infants born in the total birth population (3.3%) (range: 2.2% in Puerto Rico to 3.8% in Michigan and South Dakota).
Nationally, infants conceived with ART contributed to 3.9% of all low birthweight infants (range: 0.8% in Mississippi to 9.3% in Massachusetts) (Table 5). Among ART-conceived infants, 16.1% were low birthweight compared with 8.3% among all infants. ART-conceived infants contributed to 4.9% of all preterm infants (range: 1.4% in Alabama to 11.3% in Massachusetts) (Table 6). The percentage of preterm births was higher among infants conceived with ART (24.4%) than among all infants born in the total birth population (10.2%).
The percentage of low birthweight among singletons was 8.3% among ART-conceived infants and 6.7% among all infants born (Table 7). The percentage of preterm births among ART-conceived singleton infants was 15.4% compared with 8.5% among all singleton infants. The percentages of small for gestational age infants was 7.0% among ART-conceived infants compared with 9.3% among all infants.
Although singleton infants accounted for the majority of ART-conceived infants, multiple births from ART varied substantially among states and nationally contributed to greater than 10% of all twins, triplets and higher-order infants born in the United States. Variations in SET rates among states (or territory) were noted, which might, in part, account for high multiple birth rates observed in some states (or territory).
Reducing the number of embryos transferred and increasing use of single embryo transfer procedures, when clinically appropriate, can help reduce multiple births and related adverse health consequences for both mothers and infants (3). While risks to mothers from multiple-birth pregnancy include higher rates of caesarean delivery, gestational hypertension, and gestational diabetes, infants from multiple births are at increased risk for numerous adverse sequelae such as preterm births, birth defects, and developmental disabilities (4-7). Long-term follow-up of ART infants through integration of existing maternal and infant health surveillance systems and registries with data available from NASS might be useful for monitoring adverse outcomes on a population basis (12).
- Centers for Disease Control and Prevention. 2018 assisted reproductive technology success rates. Atlanta, GA: US Department of Health and Human Services. 2020.
- Sunderam S, Kissin DM, Zhang Y, et al. Assisted reproductive technology surveillance—United States, 2017. MMWR Surveill Summ, 2020. 69(9): p. 1-24.
- Practice Committee of the American Society for Reproductive Medicine and Practice Committee of the Society for Assisted Reproductive Technology. Guidance on the limits to the number of embryos to transfer: a committee opinion. Fertil Steril, 2021. 116(4): p. 651-654.
- Practice Bulletin No. 169. American College of Obstetricians and Gynecologists. Multifetal gestations: twin, triplet, and higher-order multifetal pregnancies. Obstet Gynecol, 2016.128:e131e46.
- MacKay AP, Berg CJ, King JC, et al. Pregnancy-related mortality among women with multifetal pregnancies. Obstet Gynecol, 2006. 107(3): p. 563-568.
- Di Tommaso M, Sisti G, Colombi I, et al. Influence of assisted reproductive technologies on maternal and neonatal outcomes in early preterm deliveries. J Gynecol Obstet Hum Reprod, 2019. 48(10): p. 845-848.
- Dawson AL, Tinker SC, Jamieson DJ, et al. Twinning and major birth defects, National Birth Defects Prevention Study, 1997-2007. J Epidemiol Community Health, 2016. 70(11): p. 1114-1121.
- Centers for Disease Control and Prevention. Assisted Reproductive Technology Surveillance Report, 2019. Atlanta (GA): US Dept of Health and Human Services; 2021.
- National Center for Health Statistics, Vital statistics data available. Natality public use file and CD-ROM. Hyattsville, MD, National Center for Health Statistics.
- Martin JA, Hamilton BE, Osterman MJK, et al. Births: final data for 2019. Natl Vital Stat Rep, 2019. 70 (2).
- US Census Bureau. 2019 population estimates. Available from https://data.census.gov/cedsci/table?t=Age%20and%20Sex&g=0100000US.04000.001&tid=ACSDP1Y2019.DP05&hidePreview=true&tp=true
- Mneimneh AS, Boulet SL, Sunderam S, et al. States Monitoring Assisted Reproductive Technology (SMART) Collaborative: Data Collection, Linkage, Dissemination, and Use. J Womens Health, 2013. 22:571-77.
Description of the data collection system
In 1995, CDC began collecting data on assisted reproductive technology (ART) procedures performed in fertility clinics in the United States as mandated by the Fertility Clinic Success Rate and Certification Act of 1992 (Public Law 102–493 [October 24, 1992]). For more details about the law, see https://www.cdc.gov/art/nass/policy.html.
ART includes all fertility treatments in which either eggs or embryos are handled outside a woman’s body. In general, ART procedures involve surgically removing eggs from a woman’s ovaries, combining them with sperm in the laboratory, and returning them to a female patient, gestational carrier, or donating them to another patient. They do not include treatments in which only sperm are handled (such as intrauterine insemination) or procedures in which a woman takes drugs only to stimulate egg production without the intention of having eggs surgically retrieved. ART includes but is not limited to in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), zygote intrafallopian transfer (ZIFT), tubal embryo transfer, egg and embryo cryopreservation, egg and embryo donation, and gestational surrogacy.
CDC collects ART data through the National ART Surveillance System (NASS), a web-based data collection system developed by CDC (https://www.cdc.gov/art/nass/index.html). Data collected include patient demographics, medical history, and infertility diagnoses; clinical information pertaining to the ART procedure type; and information regarding resultant pregnancies and births. The data file contains one record per ART procedure (i.e., cycle of treatment performed).
Data from 448 fertility clinics that provided and verified information about the outcomes of the ART cycles are reported here. During 2019, data from 41 clinics are not included here because they did not report their data as required. Given the estimated number of ART cycles performed in these nonreporting clinics, we estimate that NASS reported 98% of ART cycles performed in the United States in 2019. For more information about nonreporting clinics, see https://www.cdc.gov/art/nass/index.html.
This publication was developed and produced by the National Center for Chronic Disease Prevention and Health Promotion of the Centers for Disease Control and Prevention
National Center for Chronic Disease Prevention and Health Promotion
Karen Hacker, MD, MPH, Director
Division of Reproductive Health
Wanda D. Barfield, MD, MPH, FAAP, RADM USPHS (ret.), Director
Maternal and Infant Health Branch
Charlan Kroelinger, PhD, Chief
Suggested Citation: Sunderam, S., Zhang, Y., Jewett, A., Kissin, D. (2021). State-Specific Assisted Reproductive Technology Surveillance, United States: 2019 Data Brief. Atlanta, GA: National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention