Objective <p>Increased internet use during pregnancy may lead to excessive health-related searches and heightened anxiety, contributing to cyberchondria. However, no pregnancy-specific instrument exists to assess its severity. This study aimed to develop the Cyberchondria Severity Scale in Pregnancy (CSS-P) and evaluate its psychometric properties.</p> Methods <p>The study was conducted in three phases: (1) creation of the item pool, (2) preliminary evaluation of the items, and (3) refinement of the scale and evaluation of its psychometric properties. Instrument development guidelines were used to assess the content validity, construct validity, internal consistency, and stability over time of the instrument. Data were collected between August 2025 and December 2025 to evaluate the psychometric properties of the CSS-P. A total of 560 pregnant women participated in the study. Ethical approval was obtained from the Non-Interventional Ethics Committee of Ankara Medipol University (Decision No: E-85859696-604.01.01-5763, No: 142).</p> Results <p>EFA revealed a five-factor structure consisting of 21 items explaining 65.27% of total variance. CFA demonstrated excellent model fit (χ²/df = 1.20; GFI = 0.943; CFI = 0.994; TLI = 0.993; RMSEA = 0.024, 90% CI: 0.006–0.036). Cronbach’s α for the total scale was 0.916, and subscale values ranged from 0.925 to 0.974. Criterion validity showed statistically significant positive correlations between CSS-P subscales and CSS-12 dimensions (<i>r</i> = .21–0.64, <i>p</i> &lt; .001). Test–retest ICC values ranged from 0.85 to 0.93.</p> Conclusion <p>The 21-item CSS-P is a valid and reliable multidimensional instrument for assessing pregnancy-specific cyberchondria.</p> Impact <p>CSS-P may support the identification of maladaptive online health search behaviors during pregnancy and the evaluation of targeted interventions.</p>