How Does Sleep Affect Health for Pregnant Women?

Pregnancy is often a time of sleep loss and disturbance, but few studies have looked at how sleep affects the mother’s and child’s health. Of those studies, a handful have included non-Hispanic Blacks.

Historically and still today, women of color in the United States experience a disproportionate number of health problems related to pregnancy and childbirth—an underexplored issue. Compared with non-Hispanic White women, non-Hispanic Black women are 3 times more likely to die during pregnancy;¹ their infants are also more likely to die or be born more than 3 weeks early.² And these numbers are getting worse.

“Why are non-Hispanic Blacks lagging in maternal and child health?” asks Sanika Chirwa, Ph.D., neuroscientist and pharmacologist at Meharry Medical College. Inspired by this question, he received funding from NIMHD for a small pilot study on sleep and blood sugar in pregnant, mostly non-Hispanic Black women.

The study is not large enough to definitively conclude that poor sleep causes high blood sugar and poorer pregnancy outcomes in this population. However, it does suggest that sleep plays an important role in a pregnant woman’s risk of developing gestational diabetes, which may be higher in non-Hispanic Blacks and other racial/ethnic minorities than in Whites.³

Sleep, Pregnancy, and Blood Sugar

Many women develop high blood sugar while they are pregnant. This is called gestational diabetes. Gestational diabetes can increase the risk of other health problems for a mother and her baby. For example, women who have gestational diabetes are more likely to also have high blood pressure and to need a cesarean section. Their children are more likely to be born too early or lost in miscarriage, and both mother and child face increased chances of developing type 2 diabetes later in life.

Pregnant mothers can decrease their risk of gestational diabetes by exercising and eating healthy so that they gain appropriate amounts of weight. However, some pregnant women may have other underlying risks for gestational diabetes.

“The obvious thing that came to mind was sleep, simply by what we now know can go wrong with poor sleep quality and duration,” says Dr. Chirwa. Not sleeping enough or not getting good-quality sleep can increase a person’s risk for type 2 diabetes, metabolic syndrome, and dementia, and prior data shows that Blacks are more likely than Whites to sleep less and not as well.⁴

Although researchers and clinicians use surveys to measure how much and how well people are sleeping, Dr. Chirwa wanted to take measurements in the lab of how well and for how long expectant mothers were sleeping.

Monitoring Sleep and Health

The 38 otherwise healthy pregnant women who participated in the study completed surveys on their pregnancies, their sleep, and other aspects of their lives. All but a few were non-Hispanic Black women. Each woman was also given an actigraphic wristwatch, a wearable device that measures physical activity or rest. Each woman wore the watch for a week so it could measure her sleep. Participants also had lab tests to check their blood sugar and levels of cortisol, a hormone that fluctuates with sleep and stress.

The women did all of this during their 24th week of pregnancy, when all pregnant women should be tested for gestational diabetes. After the women delivered their babies, the team reviewed the medical records to obtain information on the babies, such as their height and weight. Twenty-two women who were not pregnant also took part in the study, as a comparison.

Pregnant women in the study got about as much sleep as women who were not pregnant. However, their sleep was worse—with many interruptions, such as waking up to go to the bathroom.

Worse sleep was associated with higher average blood sugar levels in both pregnant and nonpregnant women. Also, poor sleepers reported more signs of depression. These findings, published in the International Journal of Environmental Research and Public Health,⁵ support Dr. Chirwa’s hypothesis that poor sleep quality may increase a pregnant woman’s risk of developing gestational diabetes and associated health complications.

Improving Care and Looking Ahead

The study suggests that doctors could do more to check for warning signs of gestational diabetes in pregnant women, Dr. Chirwa says, by giving women the most common blood test for monitoring blood sugar levels linked to diabetes. He also suggested that doctors could give pregnant women a standard 10-minute questionnaire on sleep quality. With this information, doctors could advise women on how to improve their wellbeing and that of their babies, while hopefully improving the rate of healthy, full-term pregnancies for all racial and ethnic groups.

Although this study was only a pilot, it served to lay the groundwork for broader research. Next, Dr. Chirwa’s team plans to expand on their findings and develop a larger study involving other U.S. racial and ethnic groups.

“We are hoping that we will have more support to expand our study globally to include resource-limited countries, such as Zambia and Ghana where we already have research collaborators,” says Dr. Chirwa. In the meantime, the Meharry team will be studying other effects of poor sleep, such as increased risk for Alzheimer’s disease, in non-Hispanic Blacks through another NIMHD-supported project.

References

Creanga A. A., Berg, C. J., Syverson, C., Seed, K., Bruce, C., & Callaghan, W. M. (2012). Race, ethnicity and nativity differentials in pregnancy-related mortality in the United States: 1993–2006. Obstetrics and Gynecology, 120(2), 261–268. doi: 10.1097/AOG.0b013e31825cb87a
Martin, J. A., Hamilton, B. E., Osterman, M. J. K., Driscoll, A. K., & Drake, P. (2018). Births: Final data for 2017. National Vital Statistics Reports, 67(8). Hyattsville, MD: National Center for Health Statistics.
DeSisto, C. L., Kim, S. Y., & Sharma, A. J. (2014). Prevalence estimates of gestational diabetes mellitus in the United States, Pregnancy Risk Assessment Monitoring System (PRAMS), 2007–2010. Preventing Chronic Disease, 11, 130415. doi:10.5888/pcd11.130415
Kingsbury, J. H., Buxton, O. M., & Emmons, K. M. (2013). Sleep and its Relationship to Racial and Ethnic Disparities in Cardiovascular Disease. Current Cardiovascular Risk Reports, 7(5), 10.1007/s12170-013-0330-0.
Chirwa, S., Nwabuisi, C. R., Ladson, G. M., Korley, L., Whitty, J. E., Atkinson, R., & Clark, J. T. (2018). Poor sleep quality is associated with higher hemoglobin A1c in pregnant women: A pilot observational study. International Journal of Environmental Research and Public Health, 15(10), 2287. doi:10.3390/ijerph15102287