ASKDOCTORANCA

Researchers have come up with yet more causes of obesity,
diabetes and heart disease — poor nutrition of the fetus in
the womb that puts the metabolism off- kilter. A blossoming
field of medical research called fetal origins of adult
disease (FOAD) highlights just how important a healthy
environment in the womb is for both the development of the
fetus and its health as an adult.
“Babies who weigh less than five pounds at birth have a
three-fold increased risk in heart disease, but at about
eight pounds they are risk neutral,” says Dr. Mark Walker, a
high risk obstetrician in Ottawa and founder of the
Obstetrics Maternal Newborn Investigation (OMNI) group.
Larger babies are at risk, too. Studies show that babies
over nine pounds have a 10 per cent increased risk of dying
from heart disease in adulthood.
Why are heavier and lighter babies at greater risk?
Scientists are beginning to think that it’s because their
metabolism is off-balance.
When a fetus is underfed, it adapts by changing its
metabolism to become superefficient. “To survive in utero,
it changes its whole metabolic system. It extracts every
calorie it can from every bit of nutrient it gets. It
changes all the things that are involved in the metabolism
of glucose in its own metabolic system,” says Walker.
The baby’s metabolism does not get reset at birth. She goes
on to become at increased risk for heart problems later in
life.
Babies can be undernourished in the womb for a number of
reasons. For example, the pregnant mother may be living in
an area facing famine, she could be dieting or she could
have some physical abnormality that results in nutrients not
reaching the fetus.
Infants who are above average weight at birth — say 10 or 11
pounds — also have an abnormal metabolism, but it has been
altered in a different way. These heavy babies also have an
increased risk of high blood pressure and heart disease as
adults, but researchers don’t yet know exactly why. “A big
area of research right now is maternal overnutrition and its
association with obese children,” says Walker.
Scientists are learning more about this altered metabolism
theory. A study called the Ottawa Birth Cohort is following
fetuses from shortly after conception to birth. Researchers
hope to follow the children as they grow to see what
diseases they develop and how these relate to their
pre-birth environment. It’s intended to be a “from the womb
to tomb study,” says Walker.
There’s much speculation about what factors in utero may
lead to adult diseases. Researchers point fingers at
everything from medication use in pregnancy to the type of
nutrition pregnant women consume and the stress that mothers
face.