Unborn babies can be affected by maternal stress or fear

April 2013

Research proves maternal stress and fear can affect the development of unborn babies, Radio NZ listeners were told recently.

International research shows babies do respond to outside environmental influences and stress while in the womb – in some cases leading to smaller babies or predisposition to some health risks, says Gravida Director Professor Phil Baker. Research also shows the most crucial time for pre-programming the health of a baby is during or before conception, he notes.

Professor Baker comments were included in a five-part documentary series on Radio NZ National called “The Face of Fear” with presenter Sonia Sly (Part Two: Anxiety and Phobia - 29.03.13 - see notes on the rest of the series here:

He said researchers have known for some time that babies in the womb can detect light, sound and a mother’s emotional state. Using MRI technology, researchers have been able to study babies’ activities while in the womb. When a mother read a story to her baby, they could see changes in a baby’s brain that corresponded to their hearing senses.

But more recently researchers have been able to show that stress during pregnancy can translate into long term physical effects on a baby. Researchers looked at more than a million pregnancies in Denmark, taking advantage of coordinated health records linked up with social data. They took a specific marker of stress, a death or diagnosis of cancer in a child, sibling or parent during pregnancy – and looked at birth outcomes. They found higher instances of mothers going into preterm labour, higher instance of babies being smaller, and a range of long term health effects including a higher risk of schizophrenia in their offspring. “Suggesting yes, babies’ brain development is altered in some subtle way through maternal stress,” Professor Baker says.

Another study noted lower birth rates in babies born to mothers who had experienced increased fears while pregnant during the time of the terrorist attacks in London in 2005 – even though the sample group lived hundreds of miles away in North West England.

Professor Baker says research points to a complex interplay of hormones having effects in both mothers and babies, like cortisol, the stress hormone – as well as the increasingly understood area of epigenetics, where environmental influences such as steroids can switch genes on and off in babies.

These sorts of developmental affects are quite distinct from long term family genetic predispositions.

But it’s important expectant parents try not to worry or feel guilt for extreme environmental factors such as a cancer diagnosis or terrorist attacks that are outside their control.

“Although this area of research is important because it shows increased risk of these sorts of outcomes, the absolute risk is still low. For example, it might be a doubling of the likelihood of a fairly uncommon effect but overall that might not increase absolute risk,” he says in the radio documentary.

“More and more we are finding that the health of all of us, from childhood to adulthood, is influenced the most by the earliest time of our lives.

“Getting everything as right as can possibly be prior to pregnancy is one of the key preparations and is where all health professionals can help mothers the most – and emotional wellbeing may be as important as physical wellbeing.”

For mothers or women hoping to become pregnant, the key message is to look after yourself, and talk to your family or trusted medical advisor if your stress levels increase or become overwhelming.

To find out more, listen in full to the segment of the show here on Radio NZ’s website.

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