Pollution and Prematurity

Since September is National Infant Mortality Awareness Month, and since 67% of infant deaths in the first year occur in babies born prematurely, if we can lower the premature birth rate, we can lower infant mortality.

In June of this year, a new study was released, which showed a higher rate of preeclampsia and preterm birth among women who lived within 2 miles of the busy Southern California interstate system. Here’s the full study.

Abstract
Background: Preeclampsia is a major pregnancy complication leading to substantial maternal and perinatal morbidity, mortality, and preterm birth. Increasing evidence suggests air pollution adversely affects pregnancy outcomes. Yet, few studies have examined how local traffic generated emissions affect preeclampsia in addition to preterm birth.
Objectives: Examine effects of residential exposure to local traffic-generated air pollution on
preeclampsia and preterm delivery.
Methods: We identified 81,186 singleton birth records from four hospitals (1997-2006) in Los
Angeles and Orange Counties, California. We used a line-source dispersion model (CALINE4)
to estimate individual exposure to local traffic-generated NOx and PM2.5 across the entire
pregnancy. We used logistic regression to estimate effects of air pollution exposures on
preeclampsia, preterm delivery (PTD, gestational age <37 weeks), moderate preterm delivery
(MPTD, gestational age <35 weeks), and very preterm delivery (VPTD, gestational age <30
weeks).
Results: We observed elevated risks for preeclampsia and preterm birth from maternal exposure to local traffic-generated NOx and PM2.5. The risk of preeclampsia increased 33% (odds ratio (OR) =1.33, 95% confidence interval (CI): 1.18–1.49) and 42% (OR=1.42, 95% CI: 1.26–1.59) for the highest NOx and PM2.5 exposure quartiles, respectively. The risk of VPTD increased 128% (OR=2.28, 95% CI: 2.15–2.42) and 81% (OR=1.81, 95% CI: 1.71–1.92) for women in the highest NOx and PM2.5 exposure quartiles, respectively.
Conclusion: Exposure to local traffic-generated air pollution during pregnancy increases the
risk of preeclampsia and preterm birth in Southern Californian women. These results provide
further evidence that air pollution is associated with adverse reproductive outcomes.

What can be done about this? Not really sure. Move? Try to avoid the freeways, and use the car’s air conditioning system so the air goes through the filter (the researchers’ suggestion). Have a lot of plants in your house, if you live close to a high-traffic or high-emissions area? Perhaps get a personal air purifier?

It’s interesting that only about 60 years ago, doctors “knew” that the placenta acted as a barrier to protect the fetus (which it does… partially), so they gave drugs to mothers under the assumption that the baby could not be hurt. The nausea drug Thalidomide vividly proved them wrong (images of babies born after their mothers took Thalidomide here). Now, doctors are rightly concerned about the air we breathe.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: