Development and preliminary verification of a nutritional risk screening scale for pregnant and postpartum women in China: a Delphi-based single-center methodological study

Objective: Nutritional imbalances during pregnancy and the postpartum period are associated with adverse short- and long-term maternal and offspring outcomes. Nutritional risk screening scales specifically designed for Chinese pregnant and postpartum women are still lacking. This study aimed to develop and preliminarily verify a nutritional risk screening scale tailored to Chinese pregnant and postpartum women. Methods: Building on the framework of the Nutritional Risk Screening 2002, we developed a screening instrument incorporating a maternal-fetal perspective. Candidate items were generated through a literature review, followed by iterative refinement via pilot testing and three rounds of Delphi consultation. This single-center methodological study was conducted in 2025 at the Obstetrics and Gynecology Hospital of Fudan University in Shanghai. A cohort of 2,200 participants enrolled between February and April 2025 was used to determine the optimal cutoff score. Subsequently, an independent validation cohort of 3,850 participants recruited from May to August 2025 was used to evaluate the finalized scale's predictive performance. Results: The finalized scale consisted of three first-level domains and 14 second-level items. Delphi expert response rates were 91.7%, 93.9%, and 96.8%; the final authority coefficient was 0.95, and Kendall’s coefficient of concordance increased to 0.735 (all P < 0.05). A score of 3 was identified as the optimal cutoff (AUC = 0.901, 95% CI: 0.853–0.949; sensitivity = 85.0%, specificity = 92.2%). The scale demonstrated good feasibility (valid screening rate, 98.9%; mean completion time, 2.5 ± 1.1 min), good inter-rater reliability (kappa = 0.795, 95% CI: 0.743–0.847, P < 0.001), and acceptable preliminary criterion-related validity against neonatal birth weight classification as an external clinical criterion (kappa = 0.703, 95% CI: 0.669–0.737, P < 0.001). Women at nutritional risk had higher rates of abnormal neonatal birth weight and longer hospitalization. Conclusions: This new scale demonstrated good feasibility, reliability, and validity in identifying nutritional risk among Chinese pregnant and postpartum women. However, its performance has been evaluated only preliminarily at a single tertiary obstetric hospital. Multicenter validation is needed before broad clinical implementation.