State-Specific Assisted Reproductive Technology Surveillance

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 without fertility treatments to have multiple births because multiple embryos may be transferred.³ Multiple births can pose increased risks for both mothers and infants, including obstetric complications, preterm birth, and low birthweight.^4–7 This data brief provides state-specific information on US ART procedures performed in 2020 and compares birth outcomes that occurred in 2020 with outcomes for all infants born in the United States in 2020. It includes data from the 50 states, the District of Columbia, and Puerto Rico.

Data for ART procedures and ART birth outcomes were obtained from the Center for Disease Control and Prevention’s (CDC) National ART Surveillance System (NASS) for reporting years 2019 and 2020.^1,8 See the Technical Notes at the end of this data brief 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 2020.^9,10 To compare ART-conceived births in 2020 to all US births in 2020, ART-conceived births were aggregated from procedures performed in 2019 and 2020. The data are presented nationally and for the 50 States, the District of Columbia, and Puerto Rico, classified by mother’s reported state of residence at time of treatment. This data brief 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 (freezing) was performed for future ART cycles were excluded.

The number and outcomes of ART procedures performed in 2020 were first calculated. ART procedures performed per million women 15-49 years of age are presented as a proxy measure of ART use. In previous data briefs, ART procedures performed per million women aged 15-44 years were reported. This change was made given approximately 5% of ART users are older than 44 years; however, estimates from previous data briefs are not directly comparable. Data on the estimated size of the US female population were obtained from the US Census Bureau.¹¹

Average number of embryos that were transferred and the proportion of embryo-transfer procedures performed with a single embryo in 2020 were calculated for women <35 years, 35-37 years, and >37 years. The number of infants born in 2020 that were singletons, multiples (twins, triplets and higher order), with low birthweight (<2,500g), or preterm (<37 weeks gestation) was calculated for ART-conceived infants and all infants, as well as the respective percentages for each group. The proportion of ART-conceived infants among all infants with these outcomes was also calculated. The proportion of ART-conceived infants among all US births that had low birthweight, were preterm, or were small for gestational age (born at <10th percentile of birthweight for gestational age) were calculated for singleton births.

In 2020, a total of 495 fertility clinics in the United States performed ART procedures and 449 (90.7%) provided data to CDC. The states with the largest numbers of fertility clinics that provided data were California (73), New York (44), and Texas (42) (Table 1 and Figure 1)

In 2020, there were 203,164 ART procedures (range: 188 in Wyoming to 24,219 in California) performed at the 449 reporting US fertility clinics (Table 1 and Figure 2). These procedures resulted in 75,023 live-birth deliveries (range: 53 in Puerto Rico to 9,640 in California) and 79,942 infants (range: 62 in Puerto Rico to 10,224 in California) born. Nationally, 2,650 ART procedures were performed per 1 million women aged 15–49 years (range: 482 in Puerto Rico to 6,585 in the District of Columbia) (Table 1 and Figure 3). ART use rates exceeded the national rate in the District of Columbia and the following 14 states: Connecticut, Delaware,  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 the District of Columbia and the following 6 states: Connecticut, 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 83.5% among women aged <35 years (range: 38.5% in Puerto Rico to 95.8% in the District of Columbia) (Table 2 and Figure 4), 82.4% among women aged 35-37 years (range: 47.3% in Puerto Rico to 96.3% in Delaware), and 75.5% among women aged >37 years (range: 38.3% in Puerto Rico to 85.9% in Delaware).

In 2020, ART contributed to 2.0% of all infants born in the United States (range: 0.4% in Puerto Rico to 5.6% in Massachusetts) (Table 3 and Figure 5). Approximately 87.4% of ART-conceived infants were singleton infants. Approximately 12.6% of ART-conceived infants were multiples (range: 3.0% in Delaware to 43.2% in Puerto Rico) (Table 4 and Figure 6). Approximately 12.3% (9,114 of 74,346) of ART-conceived infants were twins and 0.4% (270 of 74,346) were triplets and higher-order infants. Overall, ART contributed to 8.1% of all multiple births (range: 1.9% in Mississippi to 18.9% in Hawaii) (Table 4 and Figure 7), 8.1% of all twin births and 9.4% of all triplets and higher-order births (Table 4). Almost all (97.1%) of ART-conceived multiple births were twins. The percentage of multiple births was higher among infants conceived with ART (12.6%) (range: 3.0% in Delaware to 43.2% in Puerto Rico) than among all infants born in the total birth population (3.2%) (range: 2.3% in Puerto Rico to 3.8% in Alabama).

Nationally, infants conceived with ART contributed to 3.2% of all low birthweight infants (range: 0.8% in Mississippi to 7.7% in Massachusetts) (Table 5). Among ART-conceived infants, 13.2% were low birthweight compared with 8.2% among all infants. ART-conceived infants contributed to 4.2% of all preterm infants (range: 1.2% in Alaska to 11.4% in Massachusetts) (Table 6 and Figure 8). The percentage of preterm births was higher among infants conceived with ART (20.9%) than among all infants born in the total birth population (10.1%).

The percentage of low birthweight among singletons was 7.5% among ART-conceived infants and 6.7% among all infants born (Table 7). The percentage of preterm births among ART-conceived singleton infants was 14.2% compared with 8.4% among all singleton infants. The percentages of small for gestational age infants was 6.7% 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 8% 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-conceived 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

1. Centers for Disease Control and Prevention. 2020 Assisted Reproductive Technology Fertility Clinic and National Summary Report. Centers for Disease Control and Prevention, US Dept of Health and Human Services; 2022.
2. Sunderam S, Zhang Y, Jewett A, Kissin DM. State-Specific Assisted Reproductive Technology Surveillance, United States: 2019 Data Brief. Centers for Disease Control and Prevention, US Dept of Health and Human Services; 2021.
3. 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):651–654.
4. American College of Obstetricians and Gynecologists. Multifetal gestations: twin, triplet, and higher-order multifetal pregnancies. Practice Bulletin No. 169. Obstet Gynecol. 2016;128:e131–e46.
5. MacKay AP, Berg CJ, King JC, et al. Pregnancy-related mortality among women with multifetal pregnancies. Obstet Gynecol. 2006;107(3):563–568.
6. 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):845–848.
7. 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):1114–1121.
8. Centers for Disease Control and Prevention. 2019 Assisted Reproductive Technology Fertility Clinic and National Summary Report. Centers for Disease Control and Prevention, US Dept of Health and Human Services; 2021.
9. Centers for Disease Control and Prevention. Vital Statistics Online Data Portal. Accessed December 19, 2022. https://www.cdc.gov/nchs/data_access/vitalstatsonline.htm
10. Osterman MJK, Hamilton BE, Martin JA et al. Births: final data for 2020. Natl Vital Stat Rep. 2022;70(17).
11. US Census Bureau. State Population by Characteristics: 2010-2020. Accessed December 19, 2022. https://www.census.gov/programs-surveys/popest/technical-documentation/research/evaluation-estimates/2020-evaluation-estimates/2010s-state-detail.html
12. 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;22:571–577.

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 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 (www.cdc.gov/art/nass/index.html). Data collected include patient demographics, medical history, and infertility diagnoses; clinical information about 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 449 fertility clinics that provided and verified information about the outcomes of the ART cycles are reported here. During 2020, data from 46 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 covered approximately 98% of ART cycles performed in the United States in 2020. For more information about nonreporting clinics, see www.cdc.gov/art/nass/index.html.

Beginning with 2020 data, ART procedures performed per million women 15-49 years of age are presented as a proxy measure of ART use. This change was made given approximately 5% of ART users are older than 44 years. In previous data briefs, ART use was measured as ART procedures performed per million women aged 15-44 years. Therefore, estimates from previous year data briefs are not directly comparable.

The Data Brief reports on the number and outcomes of ART procedures performed in 2020 (Tables 1 and 2 and Figures 2, 3, and 4). To compare ART-conceived births in 2020 to all US births in 2020, ART-conceived births were aggregated from procedures performed in 2019 and 2020 (Tables 3, 4, 5, 6, and 7 and Figures 5, 6, 7, and 8)

This publication was developed and produced by the National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP) of the Centers for Disease Control and Prevention (CDC).

State-Specific Assisted Reproductive Technology Surveillance, United States: 2020 Data Brief was a collaborative effort by staff members in CDC’s Division of Reproductive Health (DRH) and NCCDPHP’s Office of the Director. We wish to acknowledge Kelly Morris for her assistance in this data brief and Brian Taitt for creating the maps. We also wish to acknowledge the following ART Surveillance and Research Team members for their contributions: Anna Cofie, PhD, MPH; Carol DeSantis, MPH; Anthony Yartel, MPH.

Suggested Citation: Sunderam S, Zhang Y, Jewett A, Mardovich S, Kissin DM. State-Specific Assisted Reproductive Technology Surveillance, United States: 2020 Data Brief. Centers for Disease Control and Prevention, US Dept of Health and Human Services; 2022.