The present research examined changes in sexuality and relationship quality during pregnancy. In three studies, participants completed self-report scales of sex-related emotions, thoughts, motives, and experiences, as well as relationship quality. Study 1 (N = 361) examined the differences between pregnant and non-pregnant women in sexual and relational experiences. Study 2 (N = 25) monitored women's sexuality and relationship quality throughout the three trimesters of pregnancy. Study 3 examined gender differences in changes in sexual and relational experiences during the second and third trimesters of pregnancy among 31 cohabiting couples. The findings revealed that pregnant women were more sexually motivated by relational concerns than both their partners and non-pregnant women. Additionally, the results pointed to the involvement of two corresponding processes: Sexual enjoyment declined as pregnancy progressed, whereas relational satisfaction was relatively unchanged during pregnancy. These findings suggest that the progress of pregnancy may independently affect sexuality and relational quality.