by: Mathias Tevendale
While there have been significant advancements in medicine in recent years, premature births remain an unsolved problem. Recent studies conducted at the University of California San Francisco suggest that sleep disorders could be the likely cause of this phenomena.
Normal births typically occur at forty weeks of gestation. Premature births, also known as preterm, are those that take place at thirty-seven weeks or sooner. They are shown to be influenced by a multitude of factors including diabetes, high blood pressure, tobacco smoke, and stress.
A previously unknown risk factor has now been elucidated thanks to Dr. Jennifer Felder and her colleagues at UCSF’s Preterm Birth Initiative. The researchers looked at records from nearly three million women in the state of California between the years of 2007 and 2012. The women studied had to have delivered only a single child between twenty and forty for weeks of gestation, could not have been diagnosed with mental illness during the time of birth and the children could not have been born with any chromosomal abnormalities or any major structural birth defects.
The purpose of these control factors was to minimize any variables that might affect the data. The goal was to isolate sleep disorders and preterm births as variables and determine their correlation. Since this was a retrospective study, meaning the researchers looked back on data that had not specifically been gathered for the purpose of the study, it was difficult to define boundaries without making the sample size too small. The correlation they sought to find was between sleep disorders, a broad category, and the frequency of premature births among these women with sleep disorders. The condition “sleep disorder” was defined using the International Classification of Diseases. In general, sleep disorders are defined as any change in sleeping pattern that negatively affects health, however, the ICD categorizes these into seven categories such as insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence, circadian rhythm sleep-wake disorders, sleep-related movement disorders, parasomnias, and other sleep disorders. The study also divided the term “preterm” into three separate categories based on their delivery dates: prior to 34 weeks gestation, between 35 and 36 weeks gestation, and just before 37 weeks gestation.
The study found that the prevalence of preterm birth in women with insomnia was nearly 30% higher than in women without sleep disorders. Some sleep disorders contributed more heavily to this disparity than others. Sleep apnea, for example, showed a larger correlation with preterm birth than insomnia did, with the prevalence of preterm birth in women with sleep apnea being 40% higher than in women without sleep disorders.
While the study does seem to point towards insomnia and sleep apnea as causes for preterm birth, it is worth noting that the data only found correlations, from which causality can not be drawn. If, however, a process by which these disorders lead to preterm birth is found, then a cause and effect relationship would be found. Dr. Jennifer Felder, one of the primary researchers of the study, states that “while the biological mechanism by which insomnia and other sleep disorders affect preterm birth is unknown, some have hypothesized that increased inflammation that results from sleep disorders could be the cause.” If this is the case, then perhaps sleep disorders and preterm births alike are common symptoms of the same problem.
As Dr. Felder suggests, sleep disorders could not be causally related to preterm births at all. She states “It is possible that insomnia doesn’t have a direct effect. Insomnia could be a symptom of stress and stress could be what leads to preterm birth.” In the future, she plans to further research the mechanism by which biological factors could influence preterm birth so that the causes can be better understood.
Another important feature of the study’s findings is its demographic findings. The study found that African-American women were more likely to deliver preterm than Caucasian women. Dr. Felder suggests that if indeed stress is the main cause and sleep disorders are just the symptoms, then the study could open up a whole new question of whether or not ethnic factors such as racism could be an indirect cause of preterm birth.
While Dr. Felder confirms that the sample size did include nearly three million women, she clarifies that less than one percent of women actually were reported to have a sleeping disorder. One explanation for this could be the amount of attention that sleep disorders are given by most medical professionals. Since the importance of sleep is well known, it is possible that sometimes the details of how much sleep a pregnant woman might be getting are overlooked. Pregnant women also have trouble sleeping because they are pregnant. Because of this, having trouble sleeping might often get overlooked as a symptom rather than a possible disorder. Dr. Felder says that if anything, she hopes this study raises awareness for a particular group of people (pregnant women and their children) who might be more affected by sleep disorders than previously thought.
For now, the course of action is to treat sleep disorders with the intention of improving pregnant women’s health, as well as decrease their likelihood of preterm birth. Dr. Felder and her colleagues have started developing a virtual interface that might alleviate sleep disorders. “Sleepio,” as the application is called, utilizes Cognitive Behavioral Therapy. Also known as CBT, this approach is generally agreed upon as the most effective way to treat insomnia and depression as it does not require invasive medication. Treating pregnant women in this way could potentially have an effect on a problem that has been overlooked in the past as well as help avoid preterm births and any health consequences that might affect many newborns thereafter.