Air pollution can cause problems for many people—but it may be especially harmful in pregnant women.
National Institutes of Health researchers found that pregnant women who are exposed to certain air pollutants may be more likely to have babies admitted to the neonatal intensive care unit (NICU).
The chances of NICU admission increased significantly if mothers were exposed to traffic-related air pollution on the day before and the day of delivery.
Polluted air may cause inflammation in the mother's body. This could harm the placenta, the tissue that connects the mother and the fetus.
The research included data from 220,000 women who gave birth between 2002 and 2008. About 27,000 of those women had babies admitted to the NICU.
Researchers looked at air quality data in the area where each birth occurred and when the exposure to polluted air happened, for example, the week before delivery, the day before delivery, and the day of delivery.
The chances of NICU admission increased significantly if mothers were exposed to traffic-related air pollution on the day before and the day of delivery.
More research needs to be done to confirm the study's results. For now, pregnant women may want to limit their time outdoors during air quality advisories near the end of pregnancy.