(RxWiki News) Previous research established a link between prenatal exposure to infection and later schizophrenia. New research aimed to see if this same link was present for bipolar disorder.
A recent study found that children born to mothers who had the flu during pregnancy were at an increased risk of developing bipolar disorder with psychotic features (such as hallucinations and delusions) compared to children whose mothers did not have the flu during pregnancy.
The researchers found that having the flu during pregnancy did not affect the risk of developing bipolar disorder without psychotic features.
"Tell your OBGYN if you develop flu symptoms while pregnant."
The lead author of this study was Alan S. Brown, MD, MPH, from the Departments of Psychiatry and Epidemiology at Columbia University Medical Center, the New York State Psychiatric Institute and the Joseph L. Mailman School of Public Health in New York, New York.
The study used data on 85 participants with bipolar disorder from a previous study called the Child Health and Development Study. Thirty-six of the participants had bipolar disorder with psychotic features and 49 had bipolar disorder without psychotic features.
Bipolar disorder is a condition that causes abnormal shifts in mood, energy, activity levels and the ability to perform everyday tasks. Psychotic features are characterized by a loss of contact with reality, generally including delusions and hallucinations.
This study also included 170 control subjects, matched to the bipolar patients by birth, sex, length of mother's pregnancy and membership to Kaiser Permanente or residence in Alameda County during the first year of a participant's bipolar treatment.
All participants of the current study were born between 1959 and 1966 in Alameda County where their mothers had received obstetrics care from the Kaiser Permanente Medical Plan, Northern California.
Dr. Brown and team tested blood samples that the participants' mothers provided in the previous study at least once per trimester for any signs of influenza (the flu).
A bipolar diagnosis was obtained through medical records, Kaiser Permanente records or a mailed survey.
The findings showed that 63 of the participants' mothers had been exposed to influenza during pregnancy and 192 had not.
The participants with exposed mothers were approximately five times more likely to be diagnosed with bipolar disorder with psychotic features compared to the participants who were not born to mothers exposed to the flu during pregnancy.
The researchers also found that there was no significant association between maternal influenza exposure and bipolar disorder without psychotic features.
Dr. Brown and team suggested that maternal influenza could be connected to psychosis in general because of previous evidence showing an association between maternal influenza and schizophrenia.
"Viruses such as the flu, in mom, over the years have been associated with various problems in developing babies. This study raises yet another possible concern," said Andre Hall, MD, an OBGYN at Birth and Women's Care, PA in Fayetteville, NC.
"The take home message is that patients should follow the advice of the American College of OB/GYN who recommend flu vaccines for all pregnant women. These are safe for mom and baby," Dr. Hall told dailyRx News. "Contracting the flu while pregnant could be harmful to both mom and baby."
Dr. Brown and colleagues wrote, "Although replication in independent samples is essential, these ﬁndings imply that prevention of inﬂuenza exposure during pregnancy may decrease the incidence of bipolar disorder with psychotic features in the population."
These researchers noted a few limitations of their study. First, the researchers could not tell if the exposed mothers had been exposed prior to pregnancy or during pregnancy. Second, there was a loss of participants during follow-up, so the sample size was small. Third, the blood samples were frozen for more than 30 years.
This study was published on January 31 in The American Journal of Psychiatry.
The National Institute of Mental Health, the National Institute on Child Health and Development and the National Institute of Allergy and Infectious Diseases provided funding.