Introduction
Adverse birth outcomes are a major public health problem worldwide.
Common adverse birth outcomes include preterm birth (PTB), low birth
weight (LBW) and small for gestational age (SGA),
etc1-3. The incidence of PTB, LBW and SGA is estimated
to be 10.6 %1, 14.6%2 and
9.7%3 globally. In China, the incidence of PTB, LBW
and SGA were reported to be 6.4 %4,
5.2%5 and 10.1%6 respectively.
Adverse birth outcomes not only
increase perinatalies morbidities
and mortality, but also have lasting effects on the growth and
development of neonates and even the whole life
cycle7-9.
Pregnant women are more prone to sleep disorders due to the influence of
physiological, physical and social factors10. Existing
research has found that sleep disorders during pregnancy, including
insomnia, sleep apnea, and obstructive ventilation disorder, can lead to
adverse birth outcomes11-13. Similarly, quality and
duration of sleep at night were also reported to be associated with
adverse outcomes. Studies in other countries have reported that women
with PSQI>5 (Pittsburgh sleep quality index, PSQI) and
sleep duration during pregnancy had an increased risk of
PTB14-16, LBW and SGA17-19, while
other studies found no association between night sleep quality or
duration and adverse outcomes20-22. Several studies in
China have also reported that poor sleep quality and short sleep
duration during pregnancy are associated with an increased risk of PTB,
LBW and SGA 23-25. Other studies, however, have found
no link between sleep duration and PTB and LBW 24,26.
Limited studies have also examined the effect of napping duration on
adverse birth outcomes. A large cohort study in China found that women
who reported napping for >1 hour had a reduced risk of LBW
compared to women who did not nap 27. A small cohort
study in Brazil found no relationship27.
In general, the existing research
results are not uniform, which may be related to the differences in
regional and research conditions, so more research is necessary.
This study is based on data from the Tongji Shuangliu birth cohort
(TSBC), and aims to examine the effects of sleep quality, duration and
nap duration during pregnancy on adverse birth outcomes, so as to
provide more evidence for current research in this
field.