Introduction: Several studies have reported women's worry that sexual intercourse may harm the course of pregnancy. This worry might lead to avoidance of sexual intercourse during pregnancy., Aim: To assess if fears about harming the pregnancy are associated with avoidance of sexual intercourse during pregnancy., Methods: A cross-sectional study was conducted on 250 Vietnamese pregnant women in the first or second trimester who visited our hospital for antenatal care. We explored 5 types of fears including miscarriage/preterm labor, premature rupture of membranes, bleeding, infection, and injury to the fetus. Fears were measured by modified questions from the Reasons For Not Engaging in Sexual Activity During Pregnancy questionnaire. Using the total fear score, pregnant women were categorized into having low, moderate, and high fear., Main Outcome Measure: Not having sexual intercourse during the past 4 weeks., Results: 72 (28.8%) pregnant women had no sexual intercourse for the past 4 weeks. All types of fear were considered important among pregnant women; the more important fears were infection and injury to the fetus. In multivariable regression analysis, the prevalence of not having sexual intercourse was higher in both women who had moderate (adjusted prevalence ratio = 2.84, 95% CI 1.42-5.67) and high fear (adjusted prevalence ratio = 4.39, 95% CI 2.28-8.44)., Conclusion: Avoidance of sexual intercourse was common among Vietnamese pregnant women and was associated with the fears about harming the pregnancy. This can be a target in the health education programs for pregnancy couples. Thanh C. Phan, Long B. Hoang, Thanh K. Tran, et al. Fear-Related Reasons for Avoiding Sexual Intercourse in Early Pregnancy: A Cross-Sectional Study. Sex Med 2021;9:100430., (Copyright © 2021 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.)