Fetal development is a critical stage, and its effects can last a lifetime. However, determining the effects of maternal psychological stress on the fetus has been difficult, mainly because stressful events often cause psychological and physical effects that directly affect the mother and her child. Natural disasters serve as important case studies for understanding the impact of maternal psychological health on fetal growth, but it remains difficult to investigate the individual and specific effects of maternal psychological trauma on children.
To address this gap, Associate Professor Long Fu of Waseda University’s School of Commerce in Japan, and visiting researcher at the Columbia Center for Population Research at Columbia University in the US, along with Associate Professor Yun-Kyu Song of Seoul National University in South Korea, Associate Professor Shen Shen of Kanagawa University of Health and Welfare in Japan, and Professor Haruko Noguchi, also of Waseda University, investigated a natural disaster that caused widespread anxiety far beyond its direct material effects: the Fukushima nuclear power plant disaster that occurred in March. Researchers studied the effects of maternal anxiety about radiation exposure on the fetus. Their findings will be published online on March 7, 2026, in volume 107 of the journal. Journal of Health Economics May 1, 2026.
What motivated Fu to do this research? She explains: “Living and working in Japan, I saw firsthand how devastating the Fukushima disaster was to ordinary people, especially pregnant women and young mothers, even in areas far removed from physical danger. Fukushima’s unique geography has created a rare scientific opportunity to understand whether fear alone can harm a developing fetus.”
As part of the study, the researchers looked at three birth cohorts covering approximately 1.1 million births. The “prenatal” exposure cohort consisted of infants who: in the womb He was born during the accident, and he was born after it. The “postnatal” exposure cohort included infants born before the accident. The “placebo” cohort consisted of those born in the previous year at the same time as the postnatal group. The researchers developed a new measure of radiation anxiety using Google Trends data to examine whether birth outcomes systematically worsen as anxiety intensity increases across geographic regions.
The researchers found that preterm births were 17% to 18% more common in the prenatal cohort than in the postnatal and placebo cohorts. Birth weight was on average 22 to 26 grams lower. The proportions of very low birth weight (VLBW) and extremely low birth weight (ELBW) were approximately 50% and 77% higher, respectively, compared with other cohorts.
Researchers analyzed differences in Google searches for nuclear power plants from March 12 to April 11, 2011, compared to the same period in 2010, and created a Search Popularity Index (SPI) for each prefecture as a measure of radiation-specific anxiety. Regression analyzes showed that radiation-specific anxiety accounted for 72–79% of the difference in preterm birth and 28–37% of the difference in mean birth weight between the prenatal and other cohorts. Radiation anxiety played an even larger role in the difference between VLBW and ELBW rates. ”By inducing early delivery of at-risk fetuses or reinforcing growth restriction in vulnerable populations, radiation-related psychological stress significantly increased the incidence of severe birth outcomes associated with increased risk of persistent developmental challenges.” explains Fu.
Interestingly, the effects of radiation anxiety on birth outcomes were strongly linked to socio-economic factors. Babies born to mothers with college degrees or families in the top 25% of income groups were least affected. ”Higher education may have the advantage of greater access to accurate information about radiation risks and stronger coping resources, while higher household income may enable access to private health care and allow for more flexibility in responding to perceived threats.‘, Fu points out.
Although population-level measures of anxiety are difficult to construct, the researchers say they are encouraged by the validity of the SPI as a proxy. They believe the same strategy can be used to measure the invisible psychological effects of other large-scale crises, such as the COVID-19 pandemic or climate change.
Taken together, these findings highlight that crisis-induced psychological stress can influence fetal development and birth outcomes. In addition to providing material support, disaster response protocols should prioritize clear communication to reduce fear and anxiety. Psychological counseling should be available to pregnant women to prevent intergenerational health effects.
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Reference magazines:
Fu, R. Others. (2026). Invisible threats, visible harm: Radiation anxiety and birth outcomes after the Fukushima accident. Journal of Health Economics. DOI: 10.1016/j.jhealeco.2026.103125. https://www.sciencedirect.com/science/article/pii/S0167629626000238?via%3Dihub
