Background and objective:  Considering the importance of sexual issues in psychological health, life quality and interpersonal relationships, studying and understanding its components in different periods of life, enables us to find more efficient strategies for the consolidation the hearth (family center). This study aims to compare sexual function during pregnancy, lactation and pre- pregnancy periods.
 Materials and Methods: The present study is causal-comparative and was performed on 407 married women of Langerod city in 2012 through available sampling technique.
In order to collect data, the Female sexual Function Inventory described by Rozen et al (FSFI) was used. To analyze the data of the present study the one way variance analysis test and shuffe persuasion test was used.
 Results: The findings demonstrated a significant relationship between the average sexual function in women during pre-pregnancy, pregnancy and lactation. (p>0.000). Female sexual function significantly decreased during pregnancy and suckling periods. The highest sexual function was observed during pre-pregnancy period (22.55) and the lowest was 15.75 in pregnancy period.
 Conclusions: According to the findings of the present study, increasing knowledge of sexual function in the period of pregnancy and lactation, as well as providing training and consulting on optimal sexual function, would improve family health and consequently community health.