Velmio Research
Kseniia Storozheva and Sophie Wharrie

Air pollution exposure has increased extensively in recent years at a global level and there is considerable evidence that inhalation of air pollutants can lead to adverse health outcomes. These risks are heightened during pregnancy, where these pollutants may impact the health of your baby. 

At Velmio our mission is to empower women to make informed choices about their health. This is why we’ve just introduced a new feature that identifies your air pollution exposure risk in real-time and provides tailored recommendations on precautions you should take. No other pregnancy app helps women manage environmental risks during pregnancy, but at Velmio this kind of preventative monitoring is our top priority.

These days it is almost impossible to avoid some form of air pollution exposure during one's whole pregnancy period, but knowing the critical exposure windows is extremely helpful for targeted intervention.

Why we’re drawing attention to this issue

Air quality is probably not a key topic on your mind at your obstetrician/gynecologist visits. We often don’t think about threats we can’t visibly see until it’s too late, which is why we’re acting now to bring this topic into the spotlight. The key idea behind the Velmio app is you don’t need to constantly worry about these issues because Velmio will remind you when it matters most.

There are a multitude of studies examining the impact of environmental issues on pregnancy health. Here we give a review of the major findings, for which you can find references at the end of this article. 

Air pollutant exposure during pregnancy results in systemic inflammation and endothelial changes. This may lead to complications like a smaller placenta and utero-placental dysfunction. An inadequate supply of nutrients and oxygen to support normal growth of the fetus may lead to low birth weight and the baby being born small for gestational age [3,4,10].

The presence of maternal health conditions like chronic hypertension, diabetes mellitus and other diseases associated with systemic inflammation (such as chronic asthma and heart disease) could have an influence on the relationship between air pollution and adverse birth outcomes [10]. Exposure to air pollution and release of proinflammatory mediators in airway epithelial cells among pregnant women can trigger preterm delivery [10].

Ambient air pollution increases hypertension (high blood pressure) risk. Gestational exposure to air pollutants, such as ozone, has been linked to adverse pregnancy outcomes including hypertensive disorders of pregnancy (HDP), preeclampsia and intrauterine growth restriction (IUGR) in a number of birth cohort studies [8,9]. Early pregnancy is the most critical window for ozone exposure during pregnancy. Exposure to fine particulate matter <2.5 microns (PM2.5), particulate matter <10 microns (PM10), and nitrogen dioxide (NO2) increases risk of gestational hypertension and preeclampsia, particularly in the second trimester. Long-term exposure to PM2.5 might increase biomarkers of oxidative DNA damage.

The health impacts of exposure to air pollution during the prenatal period is especially concerning as it can impair organogenesis and organ development, which can lead to long-term complications [3]. Lung morphogenesis and development of airways begin at 4-7 weeks of gestation. Environmental exposures, including air pollution, can lead to a disturbed alveolarization - the process by which the alveoli (the principal gas exchange units of the lung) are formed. Consequently, this can lead to impairment of lung development and function after birth. 

Exposure to air pollution during pregnancy affects respiratory health with decreased lung function in infancy and childhood, increased respiratory symptoms, and the development of asthma. Prenatal PM2.5 exposure, especially among people living close to a main road, is associated with more frequent episodes of wheezing in the first 2 years of life and with recurrent pulmonary infections until the age of 7 years. NO2 exposure in the second trimester and PM10 in the first trimester of pregnancy can lead to the development of asthma at age 3-6 years. Increased prenatal PM2.5 exposure can also result in immune maturation of the fetus. Exposure to the highest quartile of pollution (PM10 and PM2.5) during pregnancy increases risk for respiratory mortality for infants [5]. Maternal SO2 exposure at a high level can lead to a low birth weight and can affect the neuromuscular coordination of a baby [11,12]. Carbon monoxide (CO) poisoning is associated with high maternal and fetal mortality rates [13]. 

How air quality is measured and reported

Air pollution is a complex mixture of the chemical compounds ozone, nitrogen dioxide, sulfur dioxide or particulate matter (PM), but only a small number of parameters are usually measured. Instruments for measuring air pollutants may vary from a simple passive sampler to advanced and expensive automatic remote monitoring systems based on light absorption spectroscopy. 

The Air Quality Index, or AQI, is the system used to warn the public when air pollution is dangerous. It uses color-coded categories with advice for each category telling you about steps you can take to reduce your exposure. Pollutants tracked by the AQI include ozone (smog) and particle pollution (tiny particles from ash, power plants and factories, vehicle exhaust, soil dust, pollen, and other pollution).

Recommendations for pregnant women

Make sure to check the air pollution alert for the day (the Velmio app is here to help with this). The European Lung Foundation recommends to avoid walking along busy streets with traffic in winter, when this type of air pollution is usually elevated. Air pollution in the summer is worse on hot days, so it is recommended to do outdoor activities in the morning when the pollution is less severe [16].

To reduce the risk of indoor air pollution exposure:

  • Do not allow smoking indoors.
  • Ensure your home is well ventilated. Air your house for 5–10 minutes several times a day, especially during and after cooking, and after taking a shower.
  • Maintain gas appliances.
  • Where there are coal, wood or open fires, make sure that chimneys are cleaned and looked after. Burn only dry and untreated wood. Do not burn refuse or packaging as it can lead to the formation of toxic substances.
  • Install alarms for smoke and carbon monoxide [17].

To reduce the risk of outdoor air pollution exposure:

  • Keep a healthy distance from the road
  • Avoid busy roads with high buildings
  • Check the air quality index of the day
  • Check the weather forecast (air pollution tends to be at its highest on hot, sunny days, while the air tends to be cleaner after rainy or windy weather)
  • Try to avoid being physically active outdoors during rush hour in busy traffic areas or other times when lots of cars will be on the roads. Choose an alternative, quieter route or another time to be active [16].

Challenges going forward

Unfortunately, in many parts of the world, governments do not share real-time air quality data with their citizens. Open access to this data is simply the first step towards tackling air pollution and raising public awareness of the detrimental effects on human health. The Velmio app has users in over 90 countries globally, so we are committed to bringing this issue into the spotlight as we work tirelessly to provide reliable data to all our users across every continent.

Furthermore, new research from a systematic review of over 32 million births shows that climate change will continue to further exacerbate these risks. Evidence suggests that extreme temperatures have a negative impact on pregnancy outcomes. These may include changes in length of gestation, birth weight, stillbirth and neonatal stress at unusually hot temperature exposures. Pregnant women are especially susceptible because the ability to regulate body temperature is compromised.

The effects of heat exposure may be immediate or lagged. These range from stillbirth rates to birth weight and gestational age. Low birth weight was previously hypothesized as a consequence of sustained heat exposure and maternal heat stress [7]. Secretion of oxytocin and heat-shock proteins as a result of heat stress is increased; it is recognized as one of the factors related to preterm birth. One of the other possible reasons for this consequence related to thermal exposure might be because of dehydration [18] It must be noted that the two temperature spectrums, cold and hot, both influence health. Exposure to cold weather and birth in colder seasons is reported to be associated with low birth weight and very low birth weight. Exposure to cold weather, cold storms and high heat has been related to preterm birth. It is documented that hypertension, eclampsia, and preeclampsia were more frequent in cold weather; cold seasons with more wind and rain [18]. 

Increasing heat waves and occurrences of extreme weather events are likely unavoidable in the coming century. Wildfires and other natural disasters also produce undesirable environmental circumstances for pregnant women. Unfortunately there isn't a lot of research available on the impact of these events on pregnancy, which makes it difficult for health professionals to provide advice to their patients.

This is why we’re building the technology now to protect you and your future children. Velmio is a tool to help you during your pregnancy journey and it is also a tool for revolutionizing pregnancy research. By using data from the Velmio app to study the impact of air quality on pregnancy outcomes we will be creating a better world where health professionals can work together with artificial intelligence to provide the highest quality health advice.