Natural disasters, such as hurricanes Harvey, Irma and Maria, the recent earthquakes in Mexico and the monsoon floods this summer in South Asia that have killed more than 1,200 people and affected millions, have direct effects not only in terms of the loss of precious lives and the destruction of infrastructure and property. Such disasters also will have latent effects on future generations through their impact on pregnant women and children in their early years of their life. These effects require the attention of governments and health care providers in the United States and around the world.
A 2013 study published in the Journal of Health Economics examined the impact of severe storms and hurricanes in Texas on birth outcomes using millions of individual birth records from 1996 through 2008. The researchers found that expectant mothers who were in their third trimester and lived within about 19 miles of a hurricane or severe storm's path were 60 percent more likely to have a newborn with abnormal birth conditions (for example, requiring a ventilator for 30 minutes or more a day) and were 30 percent more likely to have complications during labor and/or delivery. Interestingly, robust effects were not found for more conventional measures of infant health such as low birth weight or gestation length. The findings suggest that hurricanes can have subtle effects on infant health.
What is perhaps more striking is the mechanism driving such an effect. Although there is some evidence that maternal care may be disrupted during hurricanes, the authors ruled out a wide range of plausible reasons potentially explaining the effects of hurricanes on abnormal health conditions in newborns; maternal behaviors, including smoking, weight gain, use of prenatal care and even the availability of medical care, do not seem to explain these effects. Instead, the authors suggest that stress seems to be the primary mechanism at play.
Maternal stress during pregnancy has been long argued as an important risk factor for miscarriages, preterm labor and low birth weight and for having a malformed or growth-restricted baby. Furthermore, recent research studying the long-term effects of natural disasters in the U.S. found evidence that individuals who experienced a natural disaster by age 5 may be at greater risk of mental health and substance-use disorders during adulthood. Given that a growing body of evidence suggests that conditions around birth are predictive of not only later-life health but also academic performance and economic productivity in adulthood, it should be no surprise that natural disasters may have far-reaching long-term effects on both the health and economic performance of societies.
How does the evidence from the U.S. compare with similar circumstances in low-income countries? Unfortunately, the effects are usually an order of magnitude larger. According to the Germanwatch Global Climate Risk Index, of the 10 countries most affected by extreme weather between 1996 and 2015, nine were low-income or lower-middle income countries, while only one was classified as an upper-middle income country. According to an influential study that evaluated disasters in 73 nations between 1980 and 2002, countries with a per capita gross domestic product of around $2,000 have 944 deaths related to environmental disasters each year on average, compared with 180 in countries with a per capita GDP above $14,000. Another study on the impact of typhoons in the Philippines found that unearned income and excess infant mortality in the year after typhoon exposure outnumbered immediate damages and death tolls roughly by a staggering 15-to-1 ratio.
The disproportionate effects of natural diastases in low-income countries are not just felt short term; research has found that shocks during early life generally have much larger health and economic effects later in life for those living in poor countries. Not only are impoverished communities exposed to many more shocks to their health and livelihoods in general - with natural disasters adding more pain to their existing woes - but they generally have a limited capacity to treat those affected in their families and have rather limited support from their societies and governments to buffer the impact of natural disasters.
As we make our way through and beyond hurricane season and the obviously heightened attention it commands, policymakers, nongovernmental organizations and change agents like the media around the globe need to focus not just on immediate relief efforts to save lives and repair damaged property. Greater attention is needed on the hidden effects of natural disasters: the impact of psychological stress on women and children in critical stages of their lives as well as vulnerable populations in low- and middle-income countries.