Changes that occur to meet the needs of the fetus and the preparation of the woman’s body for childbirth affect sleep routine and duration. They make it difficult to fall asleep and maintain sleep (
2,
4). Poor sleep quality leads to prolonged labor, assisted delivery, more fatigue during labor, complications such as anxiety, decreased tolerance to pain, and hypertension. The probability of cesarean section, premature birth or stillbirth, prolonged duration of vaginal delivery, and low Apgar score increases in women with poor sleep quality (
2,
5,
8-
11).
Pregnancy can cause sleep disorders and exacerbate existing sleep problems (
2). Lara-Carrasco et al. (
19) determined that pregnant women reported lower sleep quality and more night awakenings than nonpregnant women. While Owusu et al. (
8) found that 86.4% of pregnant women had poor sleep quality. Sut et al. (
10) stated that 34.2% of women had poor sleep quality. Hung et al. (
2) found that the prevalence of poor sleepers (PSQI score > 5) was 66% in the third trimester. Rezaei et al. (
7) found that the mean sleep quality was 8.6 (± 2.8). Ozkan and Rathfisch (
11) found that 60.7% of participants had poor sleep quality, with a score of 7.1 (± 3.6). In this study, 89.3% of women had poor sleep quality, with a PSQI score of 8.7 (± 3.5). These results are compatible with Owusu et al. (
8) and Rezaei et al. (
7) This study was conducted on women in the third trimester. Sleep quality is impaired mainly during the third trimester (
5-
8,
10,
11). This is the reason for the high rate of pregnant women with poor sleep quality.
During the first trimester of pregnancy, women tend to sleep during the day and have an increase in total sleep duration. Total sleep duration normalizes in the second trimester. In the last trimester, the pregnant women’s sleeping habits and sleep quality are impaired (
10,
20,
21). Lee and Caughey (
22) specified that most women awoke two or three times during the third trimester and slept for an average of 7.5 hours at night. Jamalzehi et al. (
5) found that women in the 28 - 40 gestational weeks slept for an average of 8.7 (± 1.7) hours. Owusu et al. (
8) found that sleep duration was 8.3 (± 2.2) hours, 16.8% of the women slept for less than six hours, and 25.9% slept for more than 10 hours. Facco et al. (
23) found that the average sleep duration of women was lower in the third trimester. The present study determined that 90.6% of women in the third trimester woke up at least once during the night and slept for 6.5 hours per night. As can be seen from these results, when compared with the literature, the duration of sleep was low, and the rate of awakening at night was the same as the rate reported by Lee and Caughey (
22).
Anatomical, physiological, and biochemical changes in pregnancy make it difficult to fall asleep, so sleep quality is impaired. In the last trimester, pressure exerted by the fetus on the diaphragm, fetal movements, pain, birth anxiety, back pain, leg cramps, restless leg syndrome, frequent urination, reflux, heartburn, and nausea affect the sleep habits of pregnant women (
10,
20,
21). These problems experienced by pregnant women are reported to impair the quality of sleep (
22,
24). Lee and Caughey (
22) reported that the vast majority of women during the third trimester (65 - 80%) experienced frequent urination, back pain, and leg cramps. Jamalzehi et al. (
5) found that common problems included frequent urination, hot flashes, digestive problems, nausea, vomiting, and shortness of breath, and the most frequent causes of waking up included hot flashes and frequent urination. In the present study, pregnant women often experienced problems such as frequent urination (74.7%), back/waist/groin pain (72%), and leg pain (70.7%). The results of the present study are compatible with the results of other studies. The sleep quality of pregnant women with leg pain/cramps and frequent urination problems was poor.
Bad dreams have been reported to be widely seen during pregnancy because of anxiety, sleep disorders, or change in hormone levels (
25). Schredl et al. (
26) reported that the frequency of disturbing dreams was higher in pregnant women. More than 11% of women had reported nightmares once a week or more (
26). Nielsen and Paquette (
27) found that 34% of pregnant women had frightening dreams and nightmares. In their study, Lara-Carrasco et al. (
19) determined that 21% of pregnant women reported a nightmare incidence. In our study, 41.3% of women had bad dreams. These results are higher than the results reported in the literature.
The literature reports that sleep quality affects the labor (
2,
28,
29). Lee and Gay (
28) determined that sleep quality affects the duration of labor, and women with shorter sleep were 4.5 - 5.2 times more likely to have a cesarean section. Zafarghandi et al. (
29) found that sleep quality could decrease the third stage of labor. In the present study, pregnant women with poor sleep quality had a significantly shorter second stage of labor (P < 0.001). This result was associated with a small sample size. Further studies should be conducted on this subject.
Poor sleep quality reduces the ability to recover and rest, leading to decreased energy and increased fatigue (
30). Fatigue may influence the ability to endure labor pain and maternal pushing to deliver the fetus successfully during labor (
23,
31). Lack of sleep reduces the pain threshold, whereas sleep and rest increase the pain threshold (
32,
33). It was reported that sleep durations of < 5 hours were associated with increased pain. While sleep of fewer than 6 hours is associated with increased pain symptoms, it is seen that pain symptoms reduce in sleep durations of 7 - 8 or 8 - 9 hours (
3). Bebee and Lee (
30) determined a correlation between sleep five days before giving birth and pain and fatigue during labor. In this study, pregnant women’s sleep quality and sleepiness status during the day did not affect the pain score. The results of this study do not support the literature. The sleep scale used in this study examines the sleep quality during the last month, whereas Bebee and Lee (
30) used wrist actigraphy monitors in their study. Different methods used for the measurements may have influenced the results. Further studies are suggested.
5.1. Limitations
Some participants were excluded from the study due to cesarean section before or after the onset of labor because of cephalopelvic mismatch. This study’s results cannot be generalized because it was performed in a single center with a limited sample.
5.2. Conclusions
Pregnant women with poor sleep quality had a significantly shorter second stage of labor. Sleep quality and sleepiness status during the day did not affect the pain. It was determined that pregnant women wake up frequently at night and have poor sleep quality. Leg pain/cramps and frequent urination negatively affected sleep quality.