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Sunday, May 22, 2011

"Using Blackouts to Help Understand the Determinants of Infant Health"

This is based on the work of a new colleague, Alfredo Burlando:

What happens when the power goes out? Using blackouts to help understand the determinants of infant health, by Jed Friedman: Low birth weight, usually defined as less than 2500 grams at birth, is an important determinant of infant mortality. It is also significantly associated with adverse outcomes well into adulthood such as reduced school attainment and lower earnings. Maternal nutrition is a key determinant of low birth weight...

But what about the down-side risk of temporary income fluctuations - do short-lived negative income shocks have equally significant effects on low birth weight? Households may be able to prioritize the consumption and care of pregnant mothers during adverse shocks, but of course households must know about the pregnancy in the first place. This knowledge doesn’t usually manifest until after the first 6-8 weeks of pregnancy and those initial weeks of pregnancy are also critical ones to ensure the health of the fetus. One recent study by Alfredo Burlando focuses on this critical window of time when households do not yet have sufficient knowledge and thus do not sufficiently protect against the changing economic circumstances.

In May of 2008, the undersea cable that brings power to the Tanzanian island of Zanzibar was ruptured, plunging the island into a blackout that lasted 4 weeks. As a result, households employed in sectors such as manufacturing or tourism that relied on electricity experienced income declines while households in more traditional sectors such as farming did not suffer noticeable shortfalls. Fortunately any income decline was short-lived – the power was only out for 4 weeks – and in a matter of months income in all affected sectors had recovered to previous levels. Despite the brief duration of this income shock, could there have been any long-lasting consequences?

Well it turns out that infants born 7 to 9 months after the blackout were significantly smaller – an average of 75 grams smaller – than infants born within 6 months of the start of blackout or beyond 9 months after its end. This reduction translates into an 11% increase in the probability of a low weight birth. Burlando proposes reduced nutritional intake and heightened maternal stress, brought on by the blackout induced income shock, as the main transmission mechanism for lower birth weights. ...

The findings suggest that women who were known to be pregnant at the time of the black out, i.e. those who were visibly pregnant, received insurance from the shock where as women who did not realize they were yet pregnant (or who had conceived during the blackout) did not receive the same protection.

For me, the take away messages from this study are threefold:

  • These findings highlight the importance of behavioral responses and that people in the face of a crisis can be resilient when they are armed with relevant knowledge – households with women who knew they were pregnant apparently prioritized maternal nutrition. It also underscores the obvious point that any protective program that targets pregnant women faces the challenge of improving the informational barriers that prevent early pregnancy awareness.
  • The study also highlights the long-lasting effects of even very brief income shocks if (a) they occur at critical moments in fetal development and (b) households cannot fully smooth consumption or otherwise insure themselves from temporary declines. ...

    Posted by on Sunday, May 22, 2011 at 09:45 AM in Academic Papers, Economics, University of Oregon | Permalink  Comments (23)



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