Living near heavy traffic increases chances of miscarriage and newborn death.

Nov 18, 2008

de Medeiros, AAP, N Gouveia, RPP Machado, MR de Souza, GP Alencar, HM Dutilh and MF de Almeida. 2008. Traffic related air pollution and perinatal mortality: a case-control study. Environmental Health Perspectives doi:10.1289/ehp.11679.

Women who live near busy streets have an increased chance of a miscarriage or of their newborns dying, reports a study from Brazil. The findings implicate air pollution.

Women living in areas with heavy traffic flow are 1.5 times more likely to lose their babies during late gestation or have their newborns die compared to those who live in areas with less traffic, according to a Brazilian study.

The research finds a positive association between living in heavy traffic areas and risk of losing late term pregnancies or giving birth to a baby who dies during the first week of life. Previous studies have linked air pollution exposure to higher risk of preterm birth, low birth weight and perinatal mortality (i.e., death that occurs between 22 weeks gestation and first six days of life).

No prior studies, however, have investigated directly the effects of residing near these high traffic areas on fetal or infant mortality. Brazil has one of the highest perinatal death rates in the world and some cities in Brazil are highly polluted due to heavy auto and truck traffic.

In this case-control study, researchers compared the addresses of 318 women living in São Paulo, Brazil, who lost their children either during pregnancy or shortly after birth (the "cases") to those of 313 women whose children survived past 28 days (the controls). Mothers with the highest exposure to traffic-related pollution were more likely to have had a child die, and the highest risk was for young infants during the first week of life. The authors, however, could not rule out the potential confounding factors of birth weight or gestational age, which may also be impacted by traffic-related air pollution. Typically, those who live in high traffic areas are also more likely to be smokers, have low socio-economic status and have worse health care; factors that potentially add to the complexity of the observation. This study did not statistically adjust for these factors so the effects may be due to something other than air pollution. Even though, the increased risk is very high and deserves additional studies to find its cause.