Mid-upper arm circumference as a screening tool for maternal overweight and obesity among pregnant women in Eastern Ethiopia.

Currently, no globally agreed mid-upper arm circumference (MUAC) cut-offs exist to identify obesity in pregnant women. This study aimed to validate MUAC as an alternative to BMI for detecting maternal overweight/obesity and establish optimal cut-offs. An ambispective cohort study was conducted in six Eastern Ethiopian hospitals, involving 2502 singleton pregnant women enrolled before 16 weeks of gestation. Maternal weight and MUAC were measured twice (early and late pregnancy). Using early-pregnancy BMI as the gold standard, MUAC's diagnostic accuracy was evaluated via linear regression and receiver operating characteristic (ROC) curves. Optimal MUAC cut-off points were determined using Youden's index, and diagnostics were calculated to evaluate MUAC performance. A significant positive correlation was observed between BMI and MUAC (early pregnancy: r 0·69; late pregnancy: r 0·72). Optimal MUAC cut-offs for overweight were 25·95 cm (early) and 27·05 cm (late); for obesity, 27·75 cm (early) and 28·85 cm (late), with high sensitivity, specificity and predictive values. The regression equations were as follows: BMI during early pregnancy = 1·09 + 0·89 × MUAC (95 % CI 0·85, 0·93; P < 0·001) and late-pregnancy BMI = -1·69 + 0·94 × MUAC (95 % CI 0·90, 0·98; P < 0·001). The MUAC values ≥ 26 cm for maternal overweight and ≥ 28 for maternal obesity demonstrated good discriminatory performance and may serve as practical screening thresholds in resource-limited settings. Broader validation across diverse populations could facilitate the integration of MUAC into routine antenatal screening programmes, strengthening early identification and management of maternal overweight/obesity.