Washington, Aug 21 : A new study has found that pregnant women who endure the psychological stress of being in a war zone are more likely to give birth to a child who develops schizophrenia.
The study supports a growing body of literature that attributes maternal exposure to severe stress during the early months of pregnancy to an increased susceptibility to schizophrenia in the offspring.
"The stresses in question are those that would be experienced in a natural disaster such as an earthquake or hurricane, a terrorist attack, or a sudden bereavement," said lead author Dolores Malaspina M.D., M.Sc.P.H., Anita Steckler and Joseph Steckler Professor of Psychiatry at the NYU School of Medicine.
For the study, data from 88,829 people, born in Jerusalem from 1964 to 1976, were collected from the Jerusalem Perinatal Study that linked birth records to Israel's Psychiatric Registry.
The researchers discovered that the offspring of women who were in their second month of pregnancy during the height of the Arab-Israeli war in June of 1967 displayed a significantly higher incidence of schizophrenia over the following 21-33 years.
The study also showed that the pattern was gender-specific, affecting females more than males.
Following the 1967 war, females who had been in their second month of foetal life during the conflict were 4.3 times more likely to develop schizophrenia than females born at other times.
Males in their second month of foetal life were 1.2 times more likely to develop schizophrenia.
"It's a very striking confirmation of something that has been suspected for quite some time. The placenta is very sensitive to stress hormones in the mother. These hormones were probably amplified during the time of the war," said Malaspina.
The researchers point out that the study, which assessed ongoing medical records, only supports, rather than proves, the hypothesis that the greatest vulnerability to schizophrenia is in the second month of pregnancy.
Limitations to the study include a small sample population as well as the absence of information on the exact length of gestation, which makes it possible that developmental stages were underestimated.
Malaspina also points out that pregnant women in general should not be alarmed about handling daily stressors during pregnancy.
"A developing foetus requires some exposure to maternal stress hormones as it normalizes their stress functioning. But women experiencing anxiety or excessive stress would do well to address it before a planned pregnancy and to have good social support systems," she said.
The study is published in the open access journal BMC Psychiatry.