Unemployment Linked With Very Low Birth Weight
Dec. 10, 1999 (Atlanta) -- Unemployment is associated with very low birth weight (three pounds or less), according to a Scandinavian study in the December issue of the Journal of Health and Social Behavior. Thus, the associated, expensive, pre-term deliveries may be preventable to some extent. In the U.S., very low birth weight infants represent 1% of births and 64% of newborn deaths.
"The most important point is that the incidence of very low birth weight, which clinically is a very significant phenomenon, is not random over time," lead author Ralph Catalano, MD, tells WebMD. "It's influenced by factors in the community that are to some degree controllable." Catalano is professor of public health at the University of California, Berkeley.
Can the findings be generalized to the U.S.? Yes, says Catalano. There is no biological reason why the phenomenon found in this study should be peculiar to Scandinavia, he explains. In fact, he adds, the effect may be even stronger in the U.S. due to fewer support systems for people who are economically insecure or losing jobs or income.
This study used a test to compare quarterly economic rates of unemployment among Norwegian and Swedish males with the incidence of very low birth weight from 1973 through 1995.
Over this time period, quarterly economic rates of unemployment were associated with an increase in very low birth weight. The investigators estimated that if quarterly increases in male unemployment had been constrained over the 23 years, 188 very low weight births could have been prevented in Norway and approximately 329 in Sweden.
Other stressors, besides unemployment, may cause very low birth weight as well, says Catalano. "It's not that the economic stress is any different from any other stress," he says. "The reason that we use the economy as the indicator is that that is one of these encompassing stressors that affects many families and many individuals at the same point in time as opposed to the more idiosyncratic and random individual events that we have otherwise."
What is the biochemical connection between stressors and very low birth weight? That is not entirely clear, according to Catalano, although it is known that pre-term deliveries often result in babies of very low birth weight. "It appears that the clock for birth is set relatively early in pregnancy -- some people believe somewhere in the first trimester," he says. "If the mechanism perceives a relatively high level of stress hormones in the system, there is a perception that this female is stressed. The faster you get this organism [baby] delivered, the less likely it is to be subjected to whatever it is that is bothering the parent."