Psychometric properties of the Dutch London Measure of Unplanned Pregnancy for pregnant people and their partners

Context. It is often unclear what constitutes an unplanned or unintended pregnancy, and pregnancy intentions may be multidimensional dynamic. The London Measure of Unplanned Pregnancy (LMUP) measures pregnancy intentions in a manner close to the actual experience. The aim of this study is to establish a Dutch version of the LMUP (LMUP-NL) and to evaluate the reliability and validity of this version for both people who were pregnant and their partners, whatever the pregnancy outcome. Methods. A psychometric evaluation of the LMUP using observational data from the BluePrInt study and the RISE UP study was conducted with 1201 people (839 people who were pregnant and 362 partners), aged between 16-55 years. The LMUP-NL was translated based using the Flemish LMUP and the UK 2020 update, resulting in a version for people who were pregnant and one for partners. Next, the acceptability, readability, reliability, construct and convergent validity were analyzed, combining Principal Component analysis, Confirmatory Factor analysis and Mokken scale analyses. Results. The LMUP-NL demonstrated to be readable and reliable (Cronbach's alpha >0.80 for both versions). Construct validity of both versions was acceptable (CFI>0.93) and Mokken scale analyses indicated a strong scale (H-coefficient:0.68). Conclusions. The LMUP-NL is reliable and valid for people who were pregnant and their partners, regardless of the pregnancy outcome. It offers researchers and policy makers an instrument suitable to measure pregnancy intention in a multidimensional manner, constituting a closer reflection of the actual experience of pregnancy intentions.