In the past, studies have demonstrated a link between gestational influenza and schizophrenia in offspring, showing that a mother's flu during pregnancy may increase a child's risk of schizophrenia.
However, scientists have been questioning whether there is an association between exposure to influenza in the womb and bipolar disorder (BD).
According to Medilexicon's medical dictionary, Bipolar Disorder is:
"An affective disorder characterized by the occurrence of alternating manic, hypomanic, or mixed episodes and with major depresive episodes. The DSM specifies the commonly observed patterns of bipolar I and bipolar II disorder and cyclothymia."
"The identification of gestational influenza as a risk factor for BD may have potential for preventive approaches," the researchers explained.
A team of experts, led by Raveen Parboosing, M.B.Ch.B., M.Med., F.C.Path(SA)(Viro), M.S., of Albert Luthuli Central Hospital, Durban, South Africa, set out to examine whether maternal influenza during pregnancy is related to BD among their children.
The report was a nested case-control study that examined a population-based birth cohort from the the Child Health and Development Study (CHDS) - conducted between 1959 and 1966 in pregnant women receiving obstetric care from Kaiser Permanente Medical Care Plan, Northern California Region (KPNC).
The scientists used the data from the CHDS on treated maternal influenza, and potential bipolar disorder cases from the cohort were identified by database linkages of identifiers among the research group, a large county health care database, and Kaiser Permanente's database.
Mailed surveys, interviews, and data from an earlier psychiatric follow-up report on the birth cohort were also used to confirm the diagnosis of the disorder.
A total of 92 cases of bipolar disorder were identified among 214 participants and were then compared to 722 control subjects matched on date of birth, sex, and membership in KPNC or residence in Alameda County.
The experts found an almost four-fold increase in the risk of bipolar disorder after exposure to maternal influenza at any time during pregnancy.
The authors concluded:
"The findings of this study suggest that gestational infection with the influenza virus confers a nearly four-fold increased risk of BD in adult offspring. If confirmed by studies in other birth cohorts, these findings may have implications for prevention and identification of pathogenic mechanisms that lead to BD.
Further work, including serologic studies for maternal influenza antibody in archived specimens from this cohort is warranted."
Written by Sarah Glynn