Aim of the study:
This study aims to assess the psychometric properties and factor structure of the Polish translation of Prenatal Attachment Inventory (PAI) in the male version (PAI-M).

Subject or material and methods:
A cross-sectional self-assessment study was conducted among a group of 406 Polish first-time expectant fathers during three sessions (n=113, n=186, and n=107, respectively). The reliability and construct validity of the PAI were evaluated. An Exploratory Factor Analysis (EFA) and a Confirmatory Factor Analysis (CFA) using Structural Equation Modelling (SEM) were conducted.

Results:
The EFA extracted a three-factor structure (Feelings, Thoughts and beliefs, and Interactions and activities); its fit to the model has been confirmed by the CFA. Therefore, the final version of the PAI-M consists of 10 statements, comprising three factors, and demonstrates satisfactory internal consistency.

Discussion:
The structure of PAI-M found in the current study confirms and emphasizes that the mode of experiencing pregnancy and forming an attachment to an unborn child differs between men and women. Fathers were found to be less likely to manifest attachment by sharing information about how active the baby is in the womb and found it more difficult to attribute traits to the baby during this period. They manifested prenatal attachment mainly through emotions such as joy, happiness or love.

Conclusions:
The PAI-M is a reliable and valid instrument for use in Polish first-time expectant fathers to investigate the development of the paternal attachment towards the unborn child.