The aim of this study was to assess the prevalence of female sexual dysfunction (FSD) during pregnancy in a sample of women from Egypt. This prospective cohort study was conducted among pregnant women who presented to the Obstetrics Outpatient Clinic - Suez Canal University Hospital for routine antenatal care between February 2012 and February 2013. The 451 women who completed the study attended during their first trimester with a singleton pregnancy and were in a stable relationship with their partners for the last 6 months. Sexual function was assessed using the Female Sexual Function Index (FSFI) questionnaire during the 4 weeks preceding pregnancy and then in each trimester during the antenatal visits. Prevalence of FSD during pregnancy was estimated to be 68.8%. According to the FSFI, scores of all domains and total score were significantly reduced during the whole period of pregnancy (average 22.5 ± 3.7) compared to the pre-conception period (30.5 ± 5.6). However, there was significant increase of all domains and total score during the second trimester (26.6 ± 3.9) in comparison to the first and third trimesters (22.4 ± 4.1 and 18.6 ± 3.8, respectively). Total FSFI score was found to be positively correlated to pre-conception total FSFI score. However, age, parity and duration of marriage were negatively correlated. FSD is a prevalent problem during pregnancy among Egyptian women. The magnitude of the problem is highest during the third trimester while the second trimester represents the peak of sexual function during pregnancy.