Objective: The effect of sex hormones on sleep quality was studied mostly in postmenopausal women. In our study we aimed to investigate the effects of estradiol level on sleep quality in premenopausal healthy women.

Materials and Methods: One hundred healthy women without any psychiatric, gynecologic or systemic disease and assessed their sleep quality by Pittsburg Sleep Quality Index (PSQI) were enrolled to the study and their estradiol levels were obtained on the third day of their menstrueal cycles.

Results: Mean serum estradiol level was 208.12±82.028. The mean of global PSQI scores was 5.40±4.357. The mean estradiol level in “good sleepers” (PSQI score < 5) was 243.80±76.07 while the mean estradiol level in “poor sleepers” (PSQI score≥5) was 154.60±58.55, thus estradiol level was significantly higher in “good sleepers” group (t= −6.276; p<0.001).

Conclusion: We found that in normally cycling healthy women, estrogen level in normal range is also important in determining subjective sleep quality.