OBJECTIVE: Fear of childbirth (FOC) is a common problem during pregnancy and can be associated with increased maternal and fetal complications. Therefore, this study aimed to determine the frequency and intensity of FOC and some related individual, family, and social factors. METHODS: This cross-sectional study was performed on 473 nulliparous women selected by convenience sampling. Data was collected by socio-demographic characteristics and factors related to the FOC questionnaire, the Wijma delivery expectation questionnaire, the Jerabeck communication skills inventory, and the Spanier dyadic adjustment questionnaire. Data analysis was performed in SPSS version 21 using descriptive and analytic statistics (the Mann-Whitney U, the Kruskal-Wallis, the Pearson and Spearman correlation coefficients, and linear regression). RESULTS: The mean scores of FOC, communication skills, and the dyadic adjustment were 53.90 ± 25.20, 112.61 ± 24.34, and 103.00 ± 21.11, respectively. The linear regression results showed a significant relationship between FOC and communication skills, dyadic adjustment, age, knowledge of labor and its stages, socioeconomic class, satisfaction with socioeconomic class, satisfaction with monthly income, spouse's support, family's support, support of spouse's family, friends' support, fear of damage to the infant, fear of death during labor, fear of childbirth complications, confidence in the ability to give birth, and common social beliefs about natural delivery (P <
0.001). CONCLUSION: Considering the significant impact of some factors on fear of childbirth, it becomes crucial to conduct screenings to identify individuals at risk of FOC. Moreover, to prevent this fear and its adverse consequences such as a high rate of elective cesarean section, the following strategies are recommended: helping promote mothers' awareness about childbirth, offering social support through healthcare providers, and paying attention to risk factors and predictors of childbirth fear such as age and socioeconomic status, communication skills and dyadic adjustment.