Why expectant mums need to sleep well
Having good sleep isn’t just important for little ones. Our research shows that a pregnant woman’s sleep quality and duration have a marked impact on her blood glucose levels and poor sleep may put her at higher risk of gestational diabetes.
Singaporeans are among the most sleep-deprived folks in the world – in a 2014 survey by Jawbone (the makers of digitised wristbands that track sleep patterns) of 43 countries, Singapore emerged the third most sleep-starved population, after Tokyo and Seoul. And in a 2018 survey by Wakefield Research, our little red dot placed second most in need of sleep among 12 countries.
Chronic sleep deprivation can potentially cause problems like obesity, depression, compromised immunity and lower sex drive. In serious cases, it could even lead to high blood pressure, diabetes, heart attack, heart failure or stroke. Understandably, poor sleep in expectant women also has its consequences.
Tired but high on sugar
Dr Cai Shirong, a principal investigator at the Singapore Institute for Clinical Sciences (SICS), led a study to examine the influence of maternal sleep quality and nocturnal sleep duration on the risk of gestational diabetes mellitus (GDM) in a multi-ethnic Asian population like Singapore’s.
Based on data collected from 686 expectant women (376 Chinese, 186 Malay, and 124 Indian) from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) cohort, it was found that 296 women (43.1 percent) had poor sleep quality, 77 women (11.2 percent) were short sleepers, and 131 women (19.1 percent) were diagnosed with GDM.
Findings from the study also showed that poor sleep quality and short nocturnal sleep duration during pregnancy were independently associated with an increased risk of GDM, and the frequency of GDM was highest in women who reported sleeping less than six hours nightly and lowest in women with seven to eight hours of sleep a night.
Facing the not-so-sweet truth
Although the reasons for the link between poor sleep and an increased risk of GDM are unclear, some research suggests that hormonal changes in pregnancy and systematic inflammation tied to lack of sleep can lead to insulin resistance and high blood glucose levels. After all, even partial sleep deprivation over one night can increase insulin resistance, which may in turn increase blood sugar levels.
The high prevalence of GDM and type 2 diabetes in Singapore may also be explained by ethnic differences in body composition and lifestyle factors. For example, Chinese and South Indian populations tend to accumulate more abdominal fat compared with Europeans of the same BMI, which could contribute to increased insulin resistance in these Asian ethnic groups. Lifestyle factors such as increased sedentary behaviour, decreased physical labour, voluntary sleep curtailment, and easy access to energy-dense foods might also contribute to the rise of obesity and diabetes in Singapore.
High blood sugar levels during pregnancy pose health risks for both mother and baby. Mothers may face prolonged labour or caesarean delivery instead of normal delivery through the birth canal, and large-for-gestational-age babies (commonly born to mothers with GDM) are also at higher risk of obesity, diabetes and cardiovascular disease later in life.
Getting help to sleep well
While having better sleep hygiene (good sleep habits) could go some way in the fight against GDM, early screening and interventions for sleep problems in pregnancy can also potentially reduce the risk of developing maternal hyperglycaemia and GDM. Hence, the importance of healthy sleep habits and obtaining sufficient sleep should be emphasised by prenatal care providers, with the aim of improving pregnancy outcomes.
(Excerpts taken from the published paper Sleep Quality and Nocturnal Sleep Duration in Pregnancy and Risk of Gestational Diabetes Mellitus)