Relationship between nocturnal sleep quality, sleep duration, nap duration and PTB during pregnancy
Binary logistic regression was used to analyze the relationship between sleep quality, sleep duration and nap duration during pregnancy and PTB. After adjusting for confounding factors, the results showed that compared with sleeping 8 to 9 hours/night, sleeping less than 7 hours/night in pregnant women was a risk factor for increased risk of PTB (OR: 1.80, 95%CI: 1.12, 2.89), ≥ 11 hours/night remained a protective factor for reduced risk of PTB (OR: 0.53, 95%CI: 0.30, 0.93). Sleep duration in early pregnancy, sleep quality during pregnancy and nap duration were not statistically associated with the risk of PTB (P >0.05), as detailed in Table 2.