From the Guidelines
Exposure to poor air quality for one hour or more during pregnancy poses significant risks to both maternal and fetal health, and pregnant women should limit exposure to polluted air whenever possible. The primary concerns include increased risk of preterm birth, low birth weight, and pregnancy complications such as preeclampsia, as supported by recent studies 1. Air pollutants like particulate matter (PM2.5), nitrogen dioxide, and ozone can cross the placental barrier and interfere with fetal development, particularly during critical developmental windows, with some evidence suggesting that the second trimester is a critical period of exposure 1. Key risks to pregnancy with exposure to poor air quality for 1 hour or more include:
- Increased risk of preterm birth
- Low birth weight
- Pregnancy complications such as preeclampsia
- Potential long-term effects on the fetus, including respiratory problems and altered lung development, as suggested by studies on the effects of air pollution on fetal development 1. To minimize risks, pregnant women should:
- Limit outdoor activities during poor air quality events
- Wear an N95 mask if available
- Stay indoors with windows closed when possible
- Use air purifiers with HEPA filters indoors
- Maintain prescribed medication regimens for pre-existing respiratory conditions like asthma, as recommended by studies on air pollution and pregnancy outcomes 1. While a single hour of exposure may not cause immediate harm, repeated or prolonged exposures throughout pregnancy have cumulative effects, so consistent protection strategies are crucial, as highlighted by recent research on the impact of air pollution on pregnancy outcomes 1.
From the Research
Risks to Pregnancy with Exposure to Poor Air Quality
The risks to pregnancy with exposure to poor air quality for 1 hour or more are numerous and can have severe consequences for both the mother and the fetus. Some of the key risks include:
- Preterm birth: Exposure to air pollutants has been linked to an increased risk of preterm birth, which can lead to a range of health problems for the baby 2, 3.
- Low birth weight: Air pollution has also been associated with low birth weight, which can increase the risk of health problems for the baby 2, 3.
- Gestational diabetes: Exposure to air pollutants has been linked to an increased risk of gestational diabetes, which can increase the risk of health problems for both the mother and the baby 2, 3.
- Hypertensive disorders of pregnancy: Air pollution has also been associated with an increased risk of hypertensive disorders of pregnancy, which can increase the risk of health problems for both the mother and the baby 2, 3.
- Neurodevelopmental delay: Exposure to air pollutants has been linked to an increased risk of neurodevelopmental delay, including autism and attention deficit hyperactivity disorder 4.
Mechanisms of Action
The mechanisms by which air pollution affects pregnancy are not fully understood, but several possible pathways have been identified, including:
- Oxidative stress: Air pollution can cause oxidative stress, which can lead to endothelial dysfunction and vascular inflammation 2.
- Endothelial dysfunction: Endothelial dysfunction can lead to hypertension and other cardiovascular problems 2.
- Epigenetic changes: Air pollution can cause epigenetic changes, which can affect gene expression and contribute to placental dysfunction and other health problems 2.
Reducing Exposure to Air Pollution
Reducing exposure to air pollution is critical to minimizing the risks to pregnancy. Some strategies for reducing exposure include:
- Avoiding areas with high levels of air pollution: Pregnant women can reduce their exposure to air pollution by avoiding areas with high levels of pollution, such as areas near highways or industrial sites 5.
- Using air purifiers: Air purifiers can help remove pollutants from the air, reducing exposure to harmful particles 5.
- Wearing masks: Wearing masks can help reduce exposure to air pollutants, especially in areas with high levels of pollution 5.