DEAR DOCTOR K:
My husband and I are planning on having our first baby. I’ve been told that what I eat, and how much stress I have while I’m carrying the baby, could affect the baby’s health decades later. That seems hard to believe. Is there any truth to it?
It makes sense that a child’s nutrition and exercise during childhood might affect the child’s health as an adult. But it’s harder to imagine that your behavior and your health while you are pregnant could affect your child’s health for decades to come.
But over the past 35 years, many studies have found that a mother’s diet and stress levels can shape her child’s health in middle age. The first discovery of this type was that children with low-normal birth weight were much more likely to die of heart disease when they became adults. They also were more likely to get Type 2 diabetes, obesity and high blood pressure. This seems counterintuitive: These diseases are normally associated with higher-than-normal weight.
But a mother’s poor nutrition during the pregnancy can cause low birth weight. And it may lead to changes in the baby’s development in the womb. For example, in mothers with poor nutrition during a pregnancy, even if the baby has a normal birth weight, the baby’s heart, kidneys and pancreas have fewer cells than those of most babies. Decades later, when those organs start to feel the stress of having worked hard for a long time, they may get sick easier.
Some experts believe that a mother’s nutritional status even in the years before she becomes pregnant may affect the future health of her child. That’s because a woman’s eggs are formed many years before the ovary releases an egg to be fertilized.
How could a mother’s nutrition, exercise and stress during her pregnancy leave a “mark” on her baby that causes an effect only decades later, when her child is an adult? It’s not that these mother’s experiences cause harmful changes in some of her baby’s genes. Instead, these experiences can affect the tendency of the baby’s genes to be properly turned on and off. The effect on the child’s health takes decades to become obvious.
My Harvard Medical School colleague Dr. Matthew Gillman says a mother’s behavior during pregnancy, and in the months after the baby is born, can affect whether the child will be obese as an adult. A child is much more likely to become obese as an adult if the child’s mother smokes or gains excessive weight during pregnancy; breast feeds for fewer than 12 weeks; or if the child sleeps less than 12 hours per day during infancy. The chance of a child being obese as an adult is seven times greater if all of these conditions are true, compared with if none of them are true.
So, hard as it may be to believe, your activities before and during the pregnancy, and in the months following birth, can affect your child’s health decades later.