Women who come down with the flu during pregnancy may be at increased risk of
having a child who develops bipolar disorder, a new study suggests.
The chance of a child eventually developing the mental health disorder was
nearly four times higher when comparing mothers-to-be who had the flu to those
who didn't, the researchers reported.
"We don't fully understand this," said study co-author Dr Alan Brown. "The
best guess is it's an inflammatory response. It could also be a result of
fever," he noted.
"Mothers should stay away from people who have the flu," said Brown, a
professor of clinical psychiatry and clinical epidemiology at the Columbia
University College of Physicians and Surgeons in New York City.
However, he added, regarding the new findings, "women should not be greatly
concerned, because a fourfold increase is pretty high from an epidemiological
standpoint, but still the vast majority of the offspring did not get bipolar
Risk is small
Brown explained that "the risk of bipolar disorder in the population is about
1%, so if it's increased fourfold that would make it a 4% risk." Moreover, the
researchers only looked at one risk factor for bipolar disorder, not all risk
factors, which could skew these results, he noted.
Bipolar disorder, also called manic-depressive illness, causes unusual shifts
in mood, energy, activity levels and the ability to carry out routine tasks.
Bipolar disorder can be treated, and people with this illness can lead full and
productive lives, according to the US National Institute of Mental Health.
The condition often develops in the late teens or early adult years. Some
people have their first symptoms during childhood, while others may develop
symptoms as adults, the agency noted.
What the study found
For the study, researchers at Columbia University and Kaiser Permanente
identified cases of bipolar disorder by database linkages of a Northern
California health plan and a county health care system, along with data from a
Participants were mothers who gave birth between 1959 and 1966 and their
offspring. Researchers found 92 cases of bipolar disorder and compared them with
722 people matched in terms of occurrence of maternal influenza during
While the new study found an association of pregnant women getting the flu
and a higher risk of bipolar disorder in their offspring, it didn't establish a
"There is no understanding of the causal factors of this," said Dr Alan
Manevitz, a clinical psychiatrist at Lenox Hill Hospital in New York City. He
was not involved with the study.
"Pregnancy itself puts extra stress on women in general," he pointed out."Pregnancy also affects the immune system and increases the risk of getting
Flu during pregnancy increases the risk of miscarriage, premature birth and
low birth weight infants, Manevitz said.
Pregnant women should get a flu shot, both Manevitz and Brown suggested.
Other studies have shown a similar association between flu during pregnancy
and the child's risk for autism and schizophrenia - now there is this
association with bipolar disorder, Manevitz said.
"This doesn't give us any causal connection," he emphasised.
To learn more about bipolar disorder, visit the US
National Institute of Mental Health.