The purpose of our study was to elucidate the association between obstetric and psychological factors and fear of childbirth (FOC) during the third trimester of pregnancy and to identify women at risk of severe FOC in Poland. An additional goal of the study was to verify the Polish version of the Wijma Delivery Expectancy Questionnaire (W-DEQ) and to establish its psychometric characteristics. Cross-sectional study with a total of 359 women recruited during routine visits to an antenatal clinic in Poland during the third trimester (≥ 27 weeks gestation). The survey included obstetric details (parity, obstetric history and preferred mode of delivery), and standardized psychological measures: the W-DEQ (fear of childbirth) and the EPDS (depressive symptoms). We demonstrated the satisfactory psychometric properties of the Polish version of the W-DEQ. Our findings confirm the one-factor structure found by the authors of the original version of the scale. A greater FOC was reported by women with unplanned pregnancies, women whose preferred mode of delivery was a cesarean section, and women who had previously undergone psychiatric treatment. The risk factors for severe FOC were depression, unplanned pregnancy or parity, and disagreement with the birth plan proposed by the obstetrician. The W-DEQ is a widely used, valid instrument for the assessment of FOC in pregnant women and can be used in Poland. Findings support the key role of obstetric and psychological variables in predicting fear of childbirth.