This study is designed with the aim of evaluation the effectiveness of sex education with participant couples during pregnancy on sexual function and sexual satisfaction during pregnancy. This nonrandomized control trial will be done on 120 Couples attending to one of hospital centers Located in Tehran. Couples will assign to three groups, Group A: husband and pregnant women received sex education together, Group B: pregnant women received sex education alone and Group C: pregnant women received routine prenatal care, but no advice on sex (control). Data will collect by five questionnaires including FSFI, ISS, MWSSQ, IIEF and demographic characteristics. The inclusion criteria are prim gravid; living permanently with a spouse; single pregnancy. Exclusion criteria are cervix incompetent; threatened abortion. After completing a written consent, each participant completes a coded unknown pre-test questionnaire. In the intervention group A and B, the sex education classes will be held in two sessions (90 minutes) once a week for two consecutive weeks in the related health centers.Educational content in the first session includes anatomy and physiology of the female and male reproductive system, sexual cycle and orientation with erotic organ. The second session includes sexual behavior during pregnancy and safe position during pregnancy. In this study, the control group received only the center's routine care. The educational session will conduct through lectures, photo and genital models during pregnancy. Sexual function and sexual satisfaction couples will assess four weeks after the intervention, end of second and third trimester in three groups.