New York, Aug 9: Pregnant women who suffer with sleep disorders such as sleep apnoea and insomnia may be at nearly double the risk of delivering their babies before 34 weeks, an analysis has shown. The findings showed that the prevalence of preterm birth -- defined as delivery before 37 weeks' gestation -- was 14.6 per cent for women diagnosed with a sleep disorder during pregnancy compared to 10.9 per cent for women who were not. The odds of early preterm birth -- before 34 weeks -- was more than double for women with sleep apnoea and nearly double for women with insomnia. Treating sleep disorders during pregnancy could be a way to reduce the preterm rate which is about 10 per cent in the US, more than most other highly developed countries, said lead author Jennifer Felder, post-doctoral student at the University of California - San Francisco. For the study, published in the journal Obstetrics & Gynecology, the team analysed 2,265 women with a sleep disorder diagnosis during pregnancy. They were then matched to those who did not have such a diagnosis but had identical maternal risk factors for preterm birth such as a previous preterm birth, smoking during pregnancy or hypertension. "What's so exciting about this study is that a sleep disorder is a potentially modifiable risk factor," Felder said. Globally, 15 million babies are born prematurely -- more than three weeks before the typical full-term pregnancy of 40 weeks -- each year. Among these, 1.1 million die from birth-related complications while others are left with hearing impairment, learning disabilities, cerebral palsy and other health issues.