TABLE 1

The Percentage of Preterm Births by Gestational Age Groups Attributable to ART, 2015

RegionPreterm (<37 wk) Births Attributable to ART, %Very Preterm (<32 wk) Births Attributable to ART, %LPT Births (34 + 0/7–36 + 6/7 wk) Attributable to ART, %ET Births (37 + 0/7–38 + 6/7 wk) Attributable to ART, %
United States and Puerto Rico5.35.45.02.1
  • Preterm: <37 wk; very preterm: <32 wk; LPT: 34 0/7–36 6/7 wk; ET: 37 0/7–38 6/7 wk. Source: Analyses of the National ART Surveillance System (NASS) data. Written communication with the Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, April 19, 2018.