Two-Year Outcomes of Umbilical Cord Milking in Nonvigorous Infants: A Secondary Analysis of the MINVI Randomized Clinical Trial

Importance: Compared with early cord clamping (ECC), umbilical cord milking (UCM) reduces delivery room cardiorespiratory support, hypoxic-ischemic encephalopathy, and therapeutic hypothermia in nonvigorous near-term and full-term infants. However, UCM postdischarge outcomes are not known.

Objective: To determine the 2-year outcomes of children randomized to UCM or ECC at birth in the Milking in Nonvigorous Infants (MINVI) trial.

Design, setting, and participants: A secondary analysis to evaluate longer-term outcomes of a cluster-randomized crossover trial was conducted from January 9, 2021, to September 25, 2023. The primary trial took place in 10 medical centers in the US, Canada, and Poland from January 5, 2019, to June 1, 2021, and hypothesized that UCM would reduce admission to the neonatal intensive care unit compared with ECC; follow-up concluded September 26, 2023. The population included near-term and full-term infants aged 35 to 42 weeks' gestation at birth who were nonvigorous; families provided consent to complete developmental screening questionnaires through age 2 years.

Intervention: UCM and ECC.

Main outcomes and measures: Ages and Stages Questionnaire, 3rd Edition (ASQ-3) and Modified Checklist for Autism in Toddlers, Revised/Follow-Up (M-CHAT-R/F) questionnaires at ages 22 to 26 months. Intention-to-treat analysis and per-protocol analyses were used.

Results: Among 1730 newborns from the primary trial, long-term outcomes were evaluated in 971 children (81%) who had ASQ-3 scores available at 2 years or died before age 2 years and 927 children (77%) who had M-CHAT-R/F scores or died before age 2 years. Maternal and neonatal characteristics by treatment group were similar, with median birth gestational age of 39 (IQR, 38-40) weeks in both groups; 224 infants (45%) in the UCM group and 201 (43%) in the ECC group were female. The median ASQ-3 total scores were similar (UCM: 255 [IQR, 225-280] vs ECC: 255 [IQR, 230-280]; P = .87), with no significant differences in the ASQ-3 subdomains. Medium- to high-risk M-CHAT-R/F scores were also similar (UCM, 9% [45 of 486] vs ECC, 8% [37 of 441]; P = .86).

Conclusions and relevance: In this secondary analysis of a randomized clinical trial among late near-term and full-term infants who were nonvigorous at birth, ASQ-3 scores at age 2 years were not significantly different between the UCM and ECC groups. Combined with previously reported important short-term benefits, this follow-up study suggests UCM is a feasible, no-cost intervention without longer-term neurodevelopmental risks of cord milking in nonvigorous near-term and term newborns.