(NaturalNews) Women who regularly open the windows of their homes while pregnant are significantly less likely to have premature and low birth weight infants, according to a study conducted by researchers from the University of Southern California and published in the American Journal of Public Health.
Preterm birth and low birth weight are significantly associated with poor infant health, higher infant morality, and lifelong problems with the heart, breathing and behavior.
Researchers collected information on the birth weights of 1,761 Los Angeles babies, along with information from their mothers about how often windows had been kept open in the home during pregnancy, how often nail polish, hairspray and bug spray were used in the home, and whether anyone smoked inside the home.
The researchers found that in non-smoking households, the rate of preterm birth was 25 percent higher among women who rarely opened their windows than among women who frequently opened them, while the rate of low birth weight was 49 percent higher.
The researchers believe that opening windows reduces the concentration of indoor pollutants, which have been linked to an increased risk of preterm birth and low birth weight. Supporting this hypothesis, the researchers found that the rate of preterm birth was 92 percent higher in smoking households that rarely opened the windows than in non-smoking households that regularly opened windows, while the rate of low birth weight was 200 percent higher.
Low birth weight is defined as a weight of under than five pounds, eight ounces at the time of birth.
The effects of pollution
Another recent study found that exposure to outdoor air pollution also increases a mother's risk of giving birth to a preterm or low birth weight infant. This study was conducted by researchers from 14 separate institutions in nine different countries, and published in the journal Environmental Health Perspectives.
The researchers collected data on almost three million pregnancies and births, including the average exposure of each pregnant mother to particulate air pollution from sources including traffic exhaust and power plant emissions. They found that every increase in particulate exposure of 10 mcg per cubic meter was associated with an 8.9 grams (about one third of an ounce) decrease in birth weight, and a three percent higher risk of a child being officially classified as low birth weight.
Although the effect has been established by many studies, it is unclear exactly how air pollution leads to lower birth weight. The effect may arise simply from generalized stress on the mother's body, or from a more specific effect such as faulty attachment of the fetus to the placenta. In adults, particulate exposure increases the risk of asthma, diabetes, heart disease, stroke and other health problems.
Pregnant women in the study were exposed to particulate levels varying between 10 to 70 mcg per cubic meter.
"These are definitely exposures that people would have in many places around the world," researcher Woodruff said. "This study increases our confidence that the impact of air pollution on birth weight is real."