The frightening link between excessive sleep and stillbirth

* This story contains information that some readers may find scary

It can be difficult to sleep during pregnancy. A number of problems can interrupt sleep, including the frequent need to urinate, back pain, abdominal discomfort and shortness of breath, among others.

In addition, disruptive sleep during pregnancy can be risky for the fetus and help to curb growth. But a recent study suggests that excessive sleep without being disturbed can also be a problem.

Sleeping continuously for at least nine hours may be related to the risk of late stillbirth, that is, the loss or death of a baby before or during childbirth.

"The public has drawn a lot of attention to sleep deprivation and its impact on health, but not too much, too much, maybe too much – of sleep, especially with regard to pregnancy," said Louise O & Brien, Associate Professor of Neurology Research in Sleep Disorders and Obstetrics and Gynecology at the University of Michigan. "Women often worry when they get up several times during the night when they are pregnant, but that can be protective in this case."

O & # 39; Brien and her colleagues badyzed online surveys of 153 women who had a late stillbirth (after 28 weeks of pregnancy) in the month before the questionnaire and 480 women who had an ongoing pregnancy in the third trimester or having recently given birth. a baby born alive during the same period. The results, recently published in the journal Birth, suggest a link between long periods of undisturbed maternal sleep and stillbirth, regardless of other risk factors.

Stillbirth affects about 1% of all pregnancies, or about 24,000 per year in the United States, many of which are unexplained, according to the Centers for Disease Control and Prevention.

O & # 39; Brien said that women with stillbirths and women with live births reported a similar proportion of long nights of sleep before their pregnancy, which accounted for 10% in both groups.

However, nearly 30% of stillbirths reported that they had slept a long time in the last month of their pregnancy, compared to only 16% of women with a live birth.

"Since a similar proportion of women in the stillborn and alive-live group slept long before pregnancy, but during pregnancy, the stillborn group had a significant increase in the proportion of women sleeping for a long time, it would seem that it could be the change during pregnancy, that's important, "she said." Being a great sleeper for life compared to a long sleeper badociated with pregnancy could be the difference. "

She added that further research was needed, including the behavior of the autonomic nervous system, which regulates bodily functions, and the hormonal system, during late-pregnancy sleep.

She pointed out that blood pressure reached its lowest point during sleep but increased on waking, causing a brief and temporary increase. This short-term increase in blood pressure could prevent long periods of hypotension, linked to problems with fetal growth, premature birth and stillbirth, she said.

"The speculation that fewer revivals in mothers of stillborn babies could have resulted in fewer episodes of elevated blood pressure that could have been harmful to the fetus is intriguing," Shawn said. Youngstedt, sleep scientist at the University of Arizona and Phoenix VA Health Care. System, who did not participate in the study. "In general, it is thought that the" drop in blood pressure "at night is good for health, but they have made a convincing argument that a prolonged drop in blood pressure during sleep could harm the fetus. , the higher prevalence of hypertension among female controls, compared with cases, supports their argument. "

In addition, "the cases had a significantly higher prevalence of diabetes, which could partly explain the results," he said. "In addition, the authors point out a positive point: depression and anxiety, which had not been measured, could have contributed."

However, Neomi Shah, Associate Professor of Medicine, Pulmonology, Critical Care and Sleep Medicine at Mount Sinai Icahn School of Medicine, who also did not participate in the research, pointed out her limitations, especially suggesting an badociation between long uninterrupted sleep and stillbirth. but does not establish it as a cause.

In addition, the research asks participants to remember specific behaviors, a methodology that can be problematic, Shah said.

"Cases are more likely to incorrectly recall sleep duration than controls and may overestimate their sleep duration, thus demonstrating an badociation with stillbirth when in fact, it may not really exist "said Shah. "The badociation of long sleep duration and stillbirth needs to be confirmed by a real experimental study so that we can target it as a potentially modifiable risk factor for stillbirth."

The study acknowledged the potential for "recall bias", but emphasized that "we took care to minimize recall bias by limiting the study to women who gave birth to a dead baby." during the previous month, when events can be recalled. "

Smoking, advanced age of the mother, diabetes, obesity and addiction are some of the well-established risk factors for stillbirths. Maternal sleep practices have not been well studied and represent a new line of research. The study of O & # 39; Brien follows from other authors who examined the links between the mother's sleep patterns and the fetal condition, including studies suggesting an badociation between sleep asleep and stillbirth. Although the current study raises questions about the mother's sleeping position, there are not enough women who reported sleeping on their backs to perform meaningful badysis, the researchers said.

O & # 39; Brien agreed on the need for further studies, especially if they resulted in behavioral changes that could prevent stillbirths.

"Many risk factors for stillbirth can not be changed once the pregnancy is started," she said. "But we should look at all the possible interventions that can prevent poor results." Progress in reducing deaths from stillbirths has been slow, but stillbirth is an urgent global health problem that should be addressed. at the center of more research programs. "

O & # 39; Brien warned that pregnant women do not wake up deliberately during the night, waiting for scientists to know more.

"While the extremes of sleep have been badociated with health risks for the mother and baby, getting up a few times at night probably has nothing to worry about," she said. .