WHIIRS mean score of those whose BDI scores were 17 and over was found 10.7 �� 5.09, while it was 7.3 �� 4.63 for those whose BDI score was under 17. The difference was found to be statistically significant toward (P < 0.005). The difference between WHIIRS scores for those who used medicine (8.6 �� 4.85) and who did not (7.5 �� 5.06) was also found significant (P < 0.005). The present study shows that WHIIRS scores increase in parallel with the gestational week. WHIIRS mean scores of women with BMI of 25 and over (10.7 �� 5.09) were found significantly higher than those with BMI of under 25 (P < 0.05).No significant relationship was detected between WHIIRS scores and smoking and drinking tea or coffee (P < 0.05).

Table 4 presents the Backward Stepwise Logistic Regression analysis results in the model created according to bivariate analysis results which detected a significant relationship between depression probability and variables such as age, education level, BMI, BDI, existence of psychiatric disease, used medicine, and gestational trimester. Analysis results show that being in the third trimester (OR: 2.03), being 20 years old or older (OR: 2.19), and having BDI over 17 (OR: 2.63) were found to be prominent risk factors for insomnia.Table 4Advanced analysis of the risk factors associated with insomnia in pregnant women*.4. DiscussionAverage sleep duration of the pregnant women in this study is 7.7 �� 2.26h. Sleep experts indicate that quality of sleep is more important than its duration [20].

Despite the fact that average daily sleep duration of the pregnant women in this study was found to be in normal standards, more than half of the participants reported to have insomnia, which indicates their low quality of sleep. Lee et al. (2000) found an increase in the sleep duration, but a decrease in sleep quality in the AV-951 first trimester [21]. Findings of this study are compatible with those in the literature.The present study found that sleep duration decreased with the increase in the gestational trimester, and there was an increase in the WHIIRS mean scores of the participants. Logistic regression results show that the risk of developing insomnia in those in the third trimester is 2.03 times more than those in other trimesters. Lee (1999) found that women in the third gestational week had sleep problems two times more than before [22]. The related literature shows that insomnia is more common in the third trimester when the problems actually result from physical and psychosocial changes [8, 12, 23�C25]. Besides, the reasons for insomnia detected in this study (frequent visits to the toilet, not finding a comfortable position while sleeping, and restless legs) were more common in the last trimester [8, 26, 27].