J Matern Fetal Neonatal Med. 2026 Dec;39(1):2689850. doi: 10.1080/14767058.2026.2689850. Epub 2026 Jul 8.
ABSTRACT
OBJECTIVES: The PRIME randomized trial demonstrated improved neonatal outcomes using biomarker-guided risk stratification to target interventions to pregnancies at higher risk of preterm birth (PTB). This subgroup analysis evaluated its effectiveness in nulliparous pregnancies, a population with higher baseline risk and limited obstetric history to inform risk assessment.
METHODS: PRIME (NCT04301518) was a 19‑center randomized controlled trial evaluating a screen‑guided care strategy using the IGFBP4/SHBG biomarker ratio versus routine care in otherwise low‑risk singleton pregnancies. Those who were randomized to the screen-guided care arm and screened as higher risk for PTB were offered vaginal progesterone, low‑dose aspirin, and weekly telephonic nursing support. All other participants received routine care. This secondary analysis of nulliparous pregnancies of PRIME reports composite neonatal morbidity and neonatal intensive care unit (NICU) admissions. Models were adjusted for pre‑enrollment aspirin use and COVID‑19 status.
RESULTS: Of 5018 PRIME participants, 1783 were nulliparous (G1P0). Significant reductions in composite neonatal morbidity scores were identified for neonates in the screen-guided care arm versus routine care. The NICU admission rate was 12.8% in the screen-guided care arm, compared to 16.4% of neonates in the routine care arm (p = .039), which equates to a number needed to screen of 28 nulliparous pregnancies to prevent one NICU admission. When adjusted for pre-enrollment aspirin use and COVID-19 status, the screen-guided care arm had significantly fewer NICU admissions (OR 0.75; 95% CI, 0.57-0.98; p = .036). NICU admission reductions were concentrated in spontaneous PTBs of nulliparous pregnancies. The interventions were well-tolerated, and there were no serious adverse events among the nulliparous subgroup of PRIME participants in the screen-guided care arm.
CONCLUSIONS: In nulliparous PRIME trial participants, IGFBP4/SHBG screen-guided care reduced composite neonatal morbidity and NICU admissions compared to routine care. These findings support the clinical utility of biomarker-guided preventive strategies in first-time pregnancies lacking prior obstetric history.
PMID:42420160 | DOI:10.1080/14767058.2026.2689850
