Stress during pregnancy increases risk of mood disorders for female offspring

Study examines the effects of maternal cortisol levels on brain connectivity and behavior in offspring

August 16, 2018

Science Daily/Elsevier

High maternal levels of the stress hormone cortisol during pregnancy increase anxious and depressive-like behaviors in female offspring at the age of 2, reports a new study. The effect of elevated maternal cortisol on the negative offspring behavior appeared to result from patterns of stronger communication between brain regions important for sensory and emotion processing. The findings emphasize the importance of prenatal conditions for susceptibility of later mental health problems in offspring.

Interestingly, male offspring of mothers with high cortisol during pregnancy did not demonstrate the stronger brain connectivity, or an association between maternal cortisol and mood symptoms.

"Many mood and anxiety disorders are approximately twice as common in females as in males. This paper highlights one unexpected sex-specific risk factor for mood and anxiety disorders in females," said John Krystal, MD, Editor of Biological Psychiatry. "High maternal levels of cortisol during pregnancy appear to contribute to risk in females, but not males."

"This study measured maternal cortisol during pregnancy in a more comprehensive manner than prior research," said first author Alice Graham, PhD, of Oregon Health & Science University. To estimate the overall cortisol level during pregnancy, senior author Claudia Buss, PhD, of Charité University Medicine Berlin and University of California, Irvine and colleagues measured cortisol levels over multiple days in early-, mid-, and late-pregnancy. Measurements taken from the 70 mothers included in the study reflected typical variation in maternal cortisol levels. The researchers then used brain imaging to examine connectivity in the newborns soon after birth, before the external environment had begun shaping brain development, and measured infant anxious and depressive-like behaviors at 2 years of age.

"Higher maternal cortisol during pregnancy was linked to alterations in the newborns' functional brain connectivity, affecting how different brain regions can communicate with each other," said Dr. Buss. The altered connectivity involved a brain region important for emotion processing, the amygdala. This pattern of brain connectivity predicted anxious and depressive-like symptoms two years later.

The findings reveal a potential pathway through which the prenatal environment may predispose females to developing mood disorders. The study supports the idea that maternal stress may alter brain connectivity in the developing fetus, which would mean that vulnerability for developing a mood disorder is programmed from birth. This could be an early point at which the risk for common psychiatric disorders begins to differ in males and females.

https://www.sciencedaily.com/releases/2018/08/180816101944.htm

Stress during pregnancy affects the size of the baby

Growth outcome opposite due to adversity at the beginning and end of gestation period

November 28, 2017

Science Daily/University of New Mexico

Babies are physically affected by the stress level of their mother during pregnancy, new research indicates.

Researchers from The Universities of New Mexico and Göttingen, as well as the German Primate Center, have now proposed a hypothesis that largely predicts why there are highly variable patterns in the growth rates of disadvantaged offspring across 719 studies on 21 mammal species.

"The idea is that prenatal stress affects offspring in two different ways depending on the timing of the stressor during pregnancy -- yielding different outcomes before birth, after birth, and after weaning" says Andreas Berghänel, evolutionary anthropologist at The University of New Mexico and lead author of the study.

For example, prenatal maternal stress late in gestation causes mothers to invest less energy in their offspring, which leads to slower grow in the womb and during infancy. Once the baby has reached nutritional independence, however, they are no longer affected directly by their mother's provisioning, and consequently grow at the same rate as non-disadvantaged offspring. Thus, maternal stress late in gestation leads to slow growth during dependent phases, but doesn't affect growth later.

By contrast, prenatal maternal stress early in gestation additionally causes the fetus to be entirely reprogrammed to deal with a reduced life expectancy. To "make the best of a bad job," the early challenged offspring switches to an accelerated pace of life and grows and matures faster than unchallenged offspring to ensure that it reproduces before it dies. Once set on the fast track, the offspring under early prenatal maternal stress remain on this trajectory even after weaning and therefore overshoot the usual body size for age throughout development.

"These new results may bear some translational value for understanding why girls start their menstrual cycles earlier in poorer neighborhoods." In combination, an infant's acceleration of their developmental processes together with a deceleration due to reduced maternal investment could then cancel each other out during phases of intense maternal investment -- gestation and lactation. It is not until the infant is nutritionally independent that the programming effects become clear.

This new comparative study finds all of these predictions are supported in a large sample of studies that each measured the effects of prenatal stress on offspring size and growth compared to an unchallenged control group.

"We found that stress during late gestation reduces offspring growth during dependence, resulting in a reduced body size throughout development, whereas stress during early gestation results in largely unaffected growth rates during dependence but accelerated growth and increased size after weaning," says Berghänel.

All stressors seem to have the same effect, and the results are stable across a variety of experiments. Whether mothers were exposed directly to stressors via food restriction or other adversities or were experimentally manipulated to increase their "stress hormones" for example, cortisol, the patterns of offspring growth across developmental stage relative to the timing of the stressor remained the same.

Significance

These new results may bear some translational value for understanding why girls start their menstrual cycles earlier in poorer neighborhoods, why teenage pregnancies are more frequent in disadvantaged families, and why adverse conditions during early development, particularly in formula-fed children, often lead to obesity and other metabolic health problems later in life.

Maternal stress during gestation causes numerous effects on infant physiology that extend well into adulthood. Empirical tests of this hypothesis across mammals suggest that the timing of the stressor during gestation and a simultaneous consideration of maternal investment and adaptive growth plasticity effects are crucial for a full comprehension of prenatal stress effects on offspring growth. The results support an adaptive life history perspective on maternal effects that is relevant for evolutionary biology, medicine, and psychology.

https://www.sciencedaily.com/releases/2017/11/171128185924.htm

Stress during pregnancy related to infant gut microbiota

January 26, 2015

Science Daily/Radboud University

Women who experience stress during pregnancy are likely to have babies with a poor mix of intestinal microbiota and with a higher incidence of intestinal problems and allergic reactions. This could be related to psychological and physical problems as the child develops.

Stress during pregnancy is often linked to physical and psychological problems in the child. But why is this? Could the infant's gut microbiota be an underlying mechanism? An initial study of the correlation in humans has shown that babies born to mothers who experience stress have a poorer mix of intestinal microbiota.

For the purposes of this study, the stress and anxiety levels of pregnant women were measured by means of questionnaires and testing the levels of the hormone cortisol in saliva. In addition, faeces samples from 56 babies were tested from 7 days until 4 months after birth. A correlation was found between the mothers who reported high stress levels and presented high cortisol levels and the variety of microbiota in the babies' guts, even when the analyses took breastfeeding and postnatal stress into account.

Different mix of bacteria

Mothers who reported high stress levels and presented high cortisol readings had babies with more Proteobacteria and fewer lactic acid bacteria and Actinobacteria in their microbiota. This represents a poor mix of microbiota, which was also reflected in the relationship between the presence of these microbiota and a higher incidence of intestinal problems and allergic reactions among the babies in this research group.

Mechanism

'We think that our results point towards a possible mechanism for health problems in children of mothers who experience stress during pregnancy. Giving other bacteria would probably benefit these children's development,' says Carolina de Weerth, professor of developmental psychology in the Behavioural Science Institute of Radboud University Nijmegen, and corresponding author of the article that is in press in Psychoneuroendocrinology.

http://www.sciencedaily.com/releases/2015/01/150126095425.htm