Stress during pregnancy may affect baby's sex, risk of preterm birth

October 15, 2019

Science Daily/Columbia University Irving Medical Center

A new study has identified markers of maternal stress -- both physical and psychological -- that may influence a baby's sex and the likelihood of preterm birth.

It's becoming well established that maternal stress during pregnancy can affect fetal and child development as well as birth outcomes, and a new study from researchers at Columbia University Vagelos College of Physicians and Surgeons and NewYork-Presbyterian now identifies the types of physical and psychological stress that may matter most.

The study was published online in the journal PNAS, the Proceedings of the National Academy of Sciences.

"The womb is an influential first home, as important as the one a child is raised in, if not more so," says study leader Catherine Monk, PhD, professor of medical psychology at Columbia University Vagelos College of Physicians and Surgeons and director of Women's Mental Health in the Department of Obstetrics & Gynecology at NewYork-Presbyterian/Columbia University Irving Medical Center.

Because stress can manifest in a variety of ways, both as a subjective experience and in physical and lifestyle measurements, Monk and her colleagues examined 27 indicators of psychosocial, physical, and lifestyle stress collected from questionnaires, diaries, and daily physical assessments of 187 otherwise healthy pregnant women, ages 18 to 45.

About 17% (32) of the women were psychologically stressed, with clinically meaningful high levels of depression, anxiety, and perceived stress. Another 16% (30) were physically stressed, with relatively higher daily blood pressure and greater caloric intake compared with other healthy pregnant women. The majority (nearly 67%, or 125) were healthy.

Fewer Baby Boys with Mental Stress?

The study suggested that pregnant women experiencing physical and psychological stress are less likely to have a boy. On average, around 105 males are born for every 100 female births. But in this study, the sex ratio in the physically and psychologically stressed groups favored girls, with male-to-female ratios of 4:9 and 2:3, respectively.

"Other researchers have seen this pattern after social upheavals, such as the 9/11 terrorist attacks in New York City, after which the relative number of male births decreased," says Monk. "This stress in women is likely of long-standing nature; studies have shown that males are more vulnerable to adverse prenatal environments, suggesting that highly stressed women may be less likely to give birth to a male due to the loss of prior male pregnancies, often without even knowing they were pregnant."

Other Impacts of Stress

·      Physically stressed mothers, with higher blood pressure and caloric intake, were more likely to give birth prematurely than unstressed mothers.

·      Among physically stressed mothers, fetuses had reduced heart rate-movement coupling -- an indicator of slower central nervous system development -- compared with unstressed mothers.

·      Psychologically stressed mothers had more birth complications than physically stressed mothers.

Social Support Matters

The researchers also found that what most differentiated the three groups was the amount of social support a mother received from friends and family. For example, the more social support a mother received, the greater the likelihood of her having a male baby.

When social support was statistically equalized across the groups, the stress effects on preterm birth disappeared. "Screening for depression and anxiety are gradually becoming a routine part of prenatal practice," says Monk. "But while our study was small, the results suggest enhancing social support is potentially an effective target for clinical intervention."

An estimated 30% of pregnant women report psychosocial stress from job strain or related to depression and anxiety, according to the researchers. Such stress has been associated with increased risk of premature birth, which is linked to higher rates of infant mortality and of physical and mental disorders, such as attention-deficit hyperactivity disorder and anxiety, among offspring.

How a mother's mental state might specifically affect a fetus was not examined in the study. "We know from animal studies that exposure to high levels of stress can raise levels of stress hormones like cortisol in the uterus, which in turn can affect the fetus," says Monk. "Stress can also affect the mother's immune system, leading to changes that affect neurological and behavioral development in the fetus. What's clear from our study is that maternal mental health matters, not only for the mother but also for her future child."

https://www.sciencedaily.com/releases/2019/10/191015171554.htm

Context may explain why dads are happier and less stressed than moms

September 23, 2019

Science Daily/Penn State

Dads are often happier, less stressed and less tired than moms when taking care of kids, and researchers say these differences may come down to how and when childcare activities are split between parents.

In a study led by Penn State, researchers looked at childcare through the lens of a "care context." Going beyond measuring how much time mothers and fathers spend taking care of their children, the researchers also looked at the type of childcare activity, when and where it took place, who was present, and how much care was involved.

Cadhla McDonnell, a doctoral candidate in sociology and demography at Penn State, said the results suggest that while fathers in general are much more involved in their children's lives now than in the past, parenting is still highly gendered.

"There are many types of activities that can be considered childcare, but some are more strenuous or less enjoyable than others," McDonnell said. "A family trip to the playground is going to affect someone differently than changing diapers in the middle of the night, for example. In our study, we tried to capture those variations and see if they're related to the differences we see between mothers' and fathers' moods."

According to the researchers, previous work has shown that mothers tend to be more tired, stressed and unhappy than fathers during caregiving. But sociodemographic characteristics alone could not explain some of these differences. The researchers were curious about whether taking a closer look at how childcare activities were divided between parents could help explain discrepancies between parents' moods.

The researchers used data from the American Time Use Survey collected by the U.S. Census Bureau. Data included information about 4,486 childcare activities, as well as who performed the activity and that person's corresponding mood.

Additionally, the researchers analyzed each activity through the care context, which included five dimensions. The first was "activity type," and included physical (basic needs like eating and sleeping), recreational (like play and sports), educational (helping with homework or meeting with teachers), and managerial (planning doctor visits or transporting children).

The remaining dimensions included when and where the activity took place, who was present during the activity, and how much time the activity took.

The researchers found that fathers' childcare activities were more likely to be recreational and take place on the weekend, while mothers' activities were more likely to involve an infant and fit into the category of "solo parenting," that is, parenting without a partner present.

Also, the researchers found that taking the context of childcare activities into account fully explained differences in mother and father happiness, and partially explained differences in stress. It did not explain differences in tiredness.

McDonnell said the study -- recently published in the Journal of Family Issues -- suggests that moms are generally more tired and stressed than dads, and that they also are doing more childcare activities that tend to produce more stress and less happiness. But it is still not clear why these differences exist.

"Our findings show that some aspects of parenting are more enjoyable than others and that the way childcare is distributed between mothers and fathers right now brings more emotional rewards for dads than for moms," McDonnell said. "But it's impossible to say from our data whether this is the result of personal choices or whether it's a reaction to outside forces like job demands."

Additionally, the researchers found that despite their differences, one thing that remained consistent between mothers and fathers was how meaningful they found childcare.

"Traditionally caregiving has been seen as more central to women's identities than it is to men's, and that would suggest that mothers might find caring for their children more meaningful than fathers do," McDonnell said. "But that's not the case -- mothers and fathers both found caring for children highly meaningful and there is no difference by gender."

McDonnell said that in the future, additional research could focus on how gendered caregiving may have additional impacts on parents' well being.

"We know from other research that parents tend to have lower life satisfaction than non-parents, and this is especially true for women," McDonnell said. "An interesting question could be how that's related to gendered caregiving. Why do mothers seem to take on childcare in contexts that are less emotionally rewarding? For couples, how can they share caregiving in a way that is equally rewarding for both partners? These are all important questions."

https://www.sciencedaily.com/releases/2019/09/190923155026.htm