A1 Refereed original research article in a scientific journal
Outcomes of Preterm Infants Born at 22 to 23 Weeks' Gestation in 11 International Neonatal Networks
Authors: Isayama, Tetsuya; Norman, Mikael; Kusuda, Satoshi; Reichman, Brian; Lehtonen, Liisa; Lui, Kei; Adams, Mark; Vento Torres, Max; Filippi, Luca; Battin, Malcolm; Guinsburg, Ruth; Modi, Neena; Håkansson, Stellan; Klinger, Gil; de Almeida, Maria Fernanda; Helenius, Kjell; Bassler, Dirk; Su, Yi-Chen; Shah, Prakesh S.; International Network for Evaluation of Outcomes (iNeo) Investigators
Publisher: American Medical Association
Publication year: 2025
Journal:: JAMA Pediatrics
ISSN: 2168-6203
eISSN: 2168-6211
DOI: https://doi.org/10.1001/jamapediatrics.2025.2958
Web address : https://doi.org/10.1001/jamapediatrics.2025.2958
Additional information: In the Original Investigation titled “Outcomes of Preterm Infants Born at 22 to 23 Weeks’ Gestation in 11 International Neonatal Networks,”1 published online August 25, 2025, the title of Figure 2 should read, “Adjusted Incidences of Survival and Major Morbidities in Infants Born at 23 Weeks’ Gestation in 11 Neonatal Networks.” This article was corrected online.
IMPORTANCE Postnatal intensive care for preterm infants born at 22 to 23 weeks' gestation is increasing, although survival rates remain low. Information on outcomes for multiple countries or regions can be important for research, benchmarking, quality improvement, and parental counseling. OBJECTIVE To evaluate survival and major morbidities and their between-network variations in infants born at 22 to 23 weeks' gestation in 11 neonatal networks participating in the International Network for Evaluation of Outcomes (iNeo) in neonates in 12 countries or regions.
DESIGN, SETTING, AND PARTICIPANTS International registry-based cohort study of infants born at 22 to 23 weeks' gestation from January 1, 2015, through December 31, 2021, without major congenital anomalies who were admitted for neonatal intensive care in 11 national or regional neonatal consortia. Data analysis was performed from December 2, 2023, to June 15, 2025.
EXPOSURES Neonatal consortium and gestational age at birth.
MAIN OUTCOMES AND MEASURES Survival to neonatal intensive care unit discharge, major neonatal morbidities, and survival without any major morbidities.
RESULTS A total of 5019 neonates were included (1084 of 4636 neonates [23%] with a maternal age >35 years; 2641 of 5017 neonates [53%] male); among them, 846 neonates were born at 22 weeks' gestation and 4173 were born at 23 weeks' gestation. Variations between contributing networks for perinatal management at 22 and 23 weeks' gestation, respectively, include any antenatal steroids (ranges of 18%-83% and 57%-98%), cesarean birth (0%-42% and 5%-73%), and outborn (0%-26% and 0%-22%). Significant variations between contributing networks for adjusted probabilities of outcomes at 22 and 23 weeks' gestation, respectively, include survival to discharge (95% CIs of 9%-64% and 16%-80%; P < .001), grade 3 or 4 periventricular hemorrhage (PVH) or periventricular leukomalacia (PVL) (severe PVH or PVL: 24%-65% and 18%-56%; P < .001), survival without severe PVH or PVL (7%-53% and 9%-69%; P < .001), treated retinopathy of prematurity among survivors (32%-57% [P = .008] and 16%-48% [P < .001]), bronchopulmonary dysplasia among survivors (for 23 weeks only: 64%-88%; P < .001), and necrotizing enterocolitis (for 23 weeks only: 6%-28%; P < .001). Standardized incidence ratios showed significant differences in survival and major morbidities in some networks compared with a reference population from all other networks.
CONCLUSIONS Substantial international variations were identified in outcomes for infants born at 22 to 23 weeks' gestation who were admitted to 11 neonatal networks in the 12 countries or regions. The variations can be due to differences in systems, care practices, attitudes, and culture; however, identification of variation can help focus efforts toward research aimed at understanding the causal determinants of variation.
Funding information in the publication:
The International Network for Evaluation of Outcomes (iNeo) has been supported by the Canadian Institutes of Health Research (APR-126340 and PBN 150642 to Dr Shah). The Australian and New Zealand Neonatal Network is predominantly funded by membership contributions from the participating centers. The Canadian Neonatal Network is supported by a team grant from the Canadian Institutes of Health Research (CTP 87518) and by the participating centers. The Finnish Medical Birth Register is governmentally funded and kept by the National Institute for Health and Welfare. The Israel Neonatal Network very low–birth weight infant database is partially funded by the Israel Center for Disease Control and the Ministry of Health. The Neonatal Research Network of Japan is partly funded by a Health Labour Sciences Research Grant from the Ministry of Health, Labour and Welfare of Japan. The Spanish Neonatal Network is supported by funds from the Spanish Neonatal Society. The Swedish Neonatal Quality Register is funded by the Swedish government (Ministry of Health and Social Affairs), the Swedish Association of Local Communities and Regions, and the participating neonatal intensive care units (NICUs). The Swiss Neonatal Network is partially funded by the participating NICUs in the form of membership fees. This research was also supported by the Instituto de Investigación Sanitaria Carlos III (Ministry of Science, Innovation and Universities, Kingdom of Spain) (FIS17/0131 to Dr Vento Torres); Redes Temáticas de Investigación Cooperativa en Salud was funded by grant PN 2018-2021 from the Health Research Institute Carlos III, National Institute of Health Carlos III Sub-Directorate General for Research Assessment and Promotion, the European Regional Development Fund (RD16/ 0022), and grants from a regional agreement on clinical research) between Region Stockholm and Karolinska Institutet (2020-0443 to Dr Norman)
