Middle-aged adults whose mothers were obese or overweight in pregnancy have
increased risks for developing serious cardiovascular problems and dying young,
a new study shows.
The study, based on the health records of more than 37,000 people born in
Scotland between 1950 and 1976, does not explain why a mother's weight would
affect the health of an adult child decades later. Genes and upbringing may play
roles. Still, results also add to growing evidence that adverse conditions in
the womb might have profound effects long after birth, says the study, published
in the British medical journal BMJ.
"It's very difficult to tease out" causes and effects when it comes to
intergenerational health, says lead researcher Rebecca Reynolds, professor of
metabolic medicine at the University of Edinburgh. Yet she says the results lend
credence to a theory that "overnourished" fetuses may develop differences in
their brains, blood vessels, hearts or metabolisms that make it more likely for
them to become obese, unhealthy or both.
The study focused on adults ages 34 to 61 and linked their records with those
from their mothers' first prenatal doctor visits. After accounting for
socioeconomic status, mothers' ages and other differences, researchers found
that those born to obese women were 35% more likely to die, for any reason, and
29% more likely to be hospitalized for heart attacks, strokes or other
cardiovascular problems, compared with adults with normal-weight mothers.
Cardiovascular diseases and cancer were the most common causes of death.
More modest increases in illness and death were seen among the grown children of
women who were overweight but not obese.
The researchers defined overweight and obese by body mass index (BMI), a measure
that takes weight and height into account. Mothers were considered obese if
their BMIs were 30 or higher and overweight if their BMIs were between 25 and
29. It's not known whether the adults who got sick or died shared their mothers'
weight problems. The study did show that the results held up whether or not
babies were born heavy, Reynolds says.
The study "is certainly intriguing," though it lacks crucial information "on
what happens between birth and midlife" in homes where children are raised by
overweight and obese mothers, says Pam Factor-Litvak, an associate professor of
epidemiology at Columbia University in New York. It also lacks information on
fathers, she notes. Genes, shared diets and other factors need to be studied,
But the suggestion that the womb environment sets the stage for later-life
cardiovascular health and mortality is important to pursue, she says in an
In any case, there already are many good reasons for women to enter pregnancy at
healthy weights and not to gain too much during the pregnancy, says Jeanne
Conry, president of the American College of Obstetricians and Gynecologists. It
recommends women talk with their doctors about weight at every check-up, before
and between pregnancies. Women who start a pregnancy obese have an increased
risk of developing diabetes and high blood pressure, having a Cesarean section
and having a baby with birth defects, she says.
The issue is pressing, she says, because obesity among pregnant women has risen
70% in just the past decade in the USA.
Reynolds notes that just 4% of the mothers in her study were obese but that 35%
of reproductive-age U.S. women are obese and that rates are similar in Europe.
Mark Lennihan, AP