Association of Sleep Quality and Duration With Preterm Birth: The Qazvin Maternal and Neonatal Metabolic Study (QMNMS)

Background: Preterm birth (PB) is a worldwide gestational problem. Poor sleep quality and short duration have been reported as possible predisposing factors of PB in some studies. Objective: This study was conducted to investigate the roles of sleep quality/duration in the occurrence of PB. Methods: This longitudinal study was performed on pregnant women with gestational age ≤14 weeks. The sleep quality was evaluated using the Pittsburgh sleep quality index (PSQI) at the first visit and women were followed until delivery. A total of 76 women with preterm and 441 women with term delivery were compared regarding the sleep quality components, sleep duration, and long or short sleep duration. The multivariate logistic regression was performed to examine the independent association of sleep quality/duration with PB. Findings: Data from 517 participants were analyzed. PB occurred in 14.7% of participants. No significant difference of 7 items of sleep quality was observed between preterm and non-preterm groups (P>0.05 for each comparison). The total PSQI score in the preterm group was significantly higher (poorer quality) compared to the non-preterm group (5.6±2.1 vs 5.3±2.4, P=0.076). In multivariate logistic regression, each unit of worsening PSQI was independently associated with a 20% higher risk of PB occurrence. Sleep duration was not associated with PB either in unadjusted or adjusted models. Conclusion: No relationship was observed between poor sleep quality (defined as PSQI>5) and PB; however, based on our results, poorer sleep quality (as a continuous variable) can be an independent risk factor for PB.