Assessment of pandemic-related pregnancy stress from seven western countries using Rasch analyses

Introduction: This study examined psychometric properties of the Pandemic-Related Pregnancy Stress Scale (PREPS) using a Rasch Model (RM) in a large sample of pregnant women from Germany, Israel, Italy, Poland, Spain, Switzerland and the United States of America (USA). Material and methods: Rasch analyses were used to analyze a sample of 7185 pregnant women who completed the PREPS during the COVID-19 pandemic onset from April to August 2020. Psychological, sociodemographic, and obstetric factors were also collected and analyzed. Results: 12-item and 15-item PREPS versions showed acceptable fit indices. The separation index for persons on both versions allows to distinguish more than two levels of performance and for items (high and low performers). For items, it was above 30 and the strata value for items was above 45. The category probability curves for the 12-item version showed that threshold parameter categories showed a coherent order with the meaning of the response options. However, this did not occur in the 15-item version. The item-person map showed that each item is represented by an equal length of the segment, and its threshold parameters differ only in the stress severity values. Also, there is an overlap of items. Finally, DIF analysis showed many CC-rated items as well as many items with a BB rating could be revised. Conclusions: The implications of this psychometric study lie in the importance of having accurate measures of the stress that pregnant women in various parts of the world have experienced due to the COVID-19 pandemic.