title: The effect of impaired sleep on preterm labour.
abstract: BACKGROUND
  Sleep disturbance has become an important health problem for pregnant women. In fact, pregnancy-associated sleep disorder has been recognized as a distinct clinical entity. We aimed to study the relationship between sleep disturbance and preterm birth during pregnancy in a sample of Iranian women.
  
  
  METHODS
  In this analytical cohort study, 231 pregnant women in their 28th-32nd gestational week were recruited, using the multistage sampling method, from four healthcare centres in Ardabil, Iran, during 2010. The women were followed-up until 37-week gestation. One hundred and twelve women did not have sleep disturbances while 119 women had sleep disturbances. The Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), and a demographic data questionnaire were used for data collection. Data were analysed using SPSS software. Descriptive statistics, t, Chi-square, Fisher's exact, and Mann-Whitney tests were used as appropriate.
  
  
  RESULTS
  The prevalence of preterm labour was 11.8% in women with sleep disorder compared with 11.6% in women without sleep disorder (p = 0.9). Sleep duration less than eight hours, daytime dysfunction and impaired quality of life as a component of ISI showed a significant relationship with preterm birth (p = 0.02, p = 0.044, and p = 0.047, respectively).
  
  
  CONCLUSIONS
  Although daily dysfunction and lower quality of life because of sleep problems, and total sleep duration were variables associated with preterm birth, we found no significant relationship between sleep disorder and preterm birth.
authors.affiliation: Department of Midwifery and Reproductive Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Dolatian
authors.affiliation: Department of Medicine, Ardabil Branch, Islamic Azad University, Ardabil, Iran. zahraob81@yahoo.com.
authors.forename: Z
authors.initials: Z
authors.lastname: Mehraban
authors.affiliation: Department of Occupational Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: K
authors.initials: K
authors.lastname: Sadeghniat