Determinants of off-label drug acceptance in pregnancy: insights from an extended UTAUT model

Off-label drug use (OLDU) is prevalent in obstetrics due to the scarcity of medications approved for pregnancy, raising potential risks and ethical challenges, particularly concerning informed consent. In this study, we aimed to identify the key determinants of OLDU acceptance among pregnant women using an extended Unified Theory of Acceptance and Use of Technology (UTAUT) model.

A cross-sectional survey of 506 pregnant women was conducted at a tertiary hospital using a validated UTAUT-based questionnaire. Multivariable linear regression identified factors associated with behavioral intention. Six perceived risk-by-subgroup interactions were tested, with P-values adjusted via Holm-Bonferroni correction. Binary logistic regression served as a sensitivity analysis.

A total of 57.51% of participants were willing to accept OLDU when recommended by a doctor, whereas only 46.44% had understood the definition prior to the study. In the multivariable regression, trust showed the strongest positive association with behavioral intention (B = 0.380, β = 0.377, and P < 0.001), followed by facilitating conditions (B = 0.321, β = 0.337, and P < 0.001), perceived risk (B = 0.098, β = 0.102, and P = 0.002), and social influence (B = 0.091, β = 0.095, and P = 0.024). High school/technical secondary education and prior understanding of OLDU were also associated with higher behavioral intention. Subgroup analyses revealed no robust evidence of effect modification after Holm-Bonferroni correction. In the sensitivity analysis, perceived risk remained positively associated with high OLDU acceptance (OR = 1.925 and P = 0.027).

The findings highlight the importance of trust and facilitating conditions in OLDU acceptance. The positive association between perceived risk and behavioral intention indicates that recognition of potential risks and willingness to accept treatment are not necessarily mutually exclusive in this clinical decision-making context, although the explanation for this association remains uncertain. This study supports the utility of the extended UTAUT model for understanding high-risk medical decisions and underscores the importance of trust-building and transparent benefit-risk communication in clinical practice.