Infant sleep duration associated with mother's level of education and prenatal depression

Findings show greater support for mothers who experience prenatal depression or cesarean delivery may be warranted

February 27, 2019

Science Daily/University of Alberta Faculty of Medicine & Dentistry

A new study analyzing data from Canadian parents has found that babies sleep less at three months of age if their mothers do not have a university degree, experienced depression during pregnancy or had an emergency cesarean-section delivery.

The study, which examined associations between a mother's level of education, prenatal depression, method of delivery and her infant's sleep duration, was published this month in Sleep Medicine. It found that infants born to mothers without a university degree slept an average of 13.94 hours per day -- 23 minutes less than infants born to mothers with a university degree, and just short of the National Sleep Foundation guidelines of an average of 14-17 hours of sleep per day at three months of age.

The researchers analyzed data from 619 infants and their mothers participating in AllerGen's CHILD Cohort Study -- a national birth cohort study collecting a wide range of health, lifestyle, genetic and environmental exposure information from nearly 3,500 children and their families from pregnancy to adolescence.

"Sleep affects a baby's growth, learning and emotional development, and is one of the most common concerns of new parents," said Piush Mandhane, an associate professor of pediatrics at the University of Alberta and one of the study's lead authors.

"While earlier research has linked a mother's socioeconomic status, including level of education, to shorter infant sleep duration, we have not really understood the factors at play. Our study revealed that 30 per cent of the effect of maternal education on infant sleep duration is actually mediated by a mother's prenatal depression, as well as the type of delivery."

Specifically, the researchers found mothers without a university degree to be at significantly higher risk of having symptoms of depression during both the prenatal and postnatal periods, or the prenatal period alone, compared to women with a university degree.

There are several possible explanations for the association between maternal depression and infant sleep, according to co-lead author Anita Kozyrskyj, also a professor of pediatrics at the U of A. "Mothers in distress tend to have sleep problems during pregnancy, which can be 'transmitted' to the fetus via the mother's circadian clock and melatonin levels," she said. "Maternal depression and emergency cesarean section also both lead to elevated free cortisol levels, which, in turn, may cause an exaggerated stress response in infants that negatively impacts their sleep."

Further, the researchers found that the method of delivery independently predicted infant sleep duration, with infants delivered by emergency cesarean section sleeping approximately one hour less per day than infants born by vaginal delivery.

"This was an interesting finding, as we did not observe an association between shorter infant sleep and scheduled cesarean sections or vaginal deliveries," commented first author Brittany Matenchuk, an AllerGen trainee and a former Master's student at the U of A.

"While we are still at an early stage of unravelling the underlying biologic mechanisms, our study suggests that prenatal depression and birth mode are potential targets for health-care professionals and policy makers to improve infant sleep duration. Mothers who experience prenatal depression or an emergency cesarean delivery may benefit from support so that infant sleep problems do not persist into childhood."

According to the team, previous studies have shown that sleep has a large impact on infant emotional and behavioural development. It may also affect how they perform cognitively later in life.

"We need to support moms before the child is born," added Mandhane. "And if we can start to promote healthy sleep early on, three months of age onward, I think that just is better for families in general."

https://www.sciencedaily.com/releases/2019/02/190227140010.htm

Climate change poses greater risk of mental health challenges for children born to depressed mothers

The findings suggest a need for prenatal interventions in an era of growing environmental disasters

February 6, 2019

Science Daily/The Graduate Center, CUNY

Climate change poses an exponentially greater risk for mental health problems in children born to mothers with prenatal depression who also experience natural disaster-related stress. That is the message of a new study of infants born to New York City mothers shortly after Superstorm Sandy.

The study, appearing in today's issue of Infant Mental Health, builds on previous findings that disaster-related prenatal stress can have negative effects on an infant's temperament. In their new work, researchers also found that in the case of mothers who were pregnant during Superstorm Sandy and who were predisposed to depression, the effects on their babies were many times worse.

"Prenatal depression increases the risk for infants to have a difficult temperament, but when we factored in the stress of experiencing an environmental catastrophe, one plus one was not two: It was ten," said the study's lead author Yoko Nomura, a psychology professor with The Graduate Center of The City University of New York and Queens College. Nomura published her study while a faculty fellow at the Advanced Science Research Center at The Graduate Center. "Our research found that, compared to other babies, infants born to women who were prenatally depressed and pregnant during Superstorm Sandy had higher rates of distress and lower rates of pleasure-seeking activities."

The study considered 310 pairs of mothers and children, recruited from clinics that serve patients from around the boroughs of New York City. The researchers assessed the mothers' depression symptoms, and mothers reported their infants' temperament via a questionnaire six months after birth.

Infants of depressed mothers displayed greater distress and fear, less smiling and laughter, and lower soothability and cuddliness compared to infants of mothers with lower scores for depression. The infants of depressed mothers who were pregnant during Sandy displayed even worse temperament.

In a 2018 study by several of the same authors, researchers concluded that a mother's stress impacts her child's temperament during the early years of childhood, and they demonstrated that this was true for children born during or close to the time of Superstorm Sandy.

The researchers posited that epigenetic responses to external stressors may be the cause of the increased incidents and intensity of mental health challenges for these infants.

"The combination of environmental stressors and biology may compromise gene expression and cause an excessive amount of cortisol to be passed from the mother to the fetus, resulting in infants having poorer emotional regulation, shyness and fearfulness," said co-author Jessica Buthmann, a Graduate Center doctoral student (Psychology) and Queens College adjunct professor.

Nomura's team recommends monitoring and screening for at-risk mothers during future environmental events as the rising incidents of environmental disasters are likely to put more mothers and infants at risk for climate change-related mental health problems.

"The take-home point is that we should be mindful to look out for the high-risk mothers, because the long-term consequences for the mental health of their offspring could be eased with proper intervention," Nomura said.

https://www.sciencedaily.com/releases/2019/02/190206131943.htm