Outcomes of Infants Born at 21 Weeks' Gestational Age.

Importance: Advances in medical care and clinician experience have lowered the gestational age at which resuscitation is considered for extremely premature infants. Some centers now offer trials of resuscitation at 21 weeks' gestational age. Minimal data are available to guide this practice. Objective: To describe morbidities and outcomes of resuscitated infants at 21 weeks' gestational age. Design, Setting, and Participants: This retrospective case series included all infants born at 21 weeks' gestational age in a single-center level IV academic neonatal intensive care unit (NICU) at the University of Iowa from January 1, 2020, through February 28, 2025. Data were analyzed from April 1 to August 15, 2025. Exposure: Extremely preterm birth at a gestational age of 21 weeks. Main Outcomes and Measures: Demographic characteristics, therapies, morbidities, and test results were collected throughout hospitalizations from electronic medical records for extremely premature infants who received any attempted resuscitation and their mothers, including hourly cardiorespiratory data for the first 72 hours for infants admitted to the NICU. Postdischarge outcomes through the end of the study period were collected as available. Results: Twenty-two infants were born alive at 21 weeks' gestational age during the study period, and an additional 230 were stillborn. Resuscitation was attempted in 17 (77%) of the infants born alive; of these, 6 (35%) survived to discharge from the NICU (earliest in 2021; youngest, 21 weeks, 0 days; birth weight, 285-430 g), 1 (6%) remained hospitalized, and 10 (59%) died. All births were inborn vaginal deliveries. Infants who survived (including the infant who remained hospitalized) were less likely part of a multiple gestation compared with those who did not (1 of 7 [14%] vs 6 of 10 [60%]) and more likely exposed to a complete course of antenatal corticosteroids (3 of 7 [43%] vs 0 of 10). Most of the infants who survived had early cardiorespiratory instability treated with vasoactive medications and/or inhaled nitric oxide (5 [71%]). Three (43%) had no or grade 1 intraventricular hemorrhage (IVH), 2 (29%) had grade 2 IVH, and 2 had severe (grade 3) IVH (29%); none required neurosurgical intervention. The 6 infants who were discharged received low-flow supplemental oxygen, and none required tracheostomy. Rates of resuscitation increased during the study period. Conclusions and Relevance: In this case series of infants born alive at 21 weeks' gestational age, selective resuscitation resulted in 35% survival to discharge, in some cases with minimal morbidities. These descriptive data may prompt prospective study and reporting at this gestational age. Long-term outcome data are needed.