Achieving India's air quality target across south Asia may prevent 7% of pregnancy losses: Lancet study

Pregnancy loss associated with air pollution was found to be more common in the northern plain regions in India and Pakistan.

Air pollution is a serious issue in India. Now, a Lancet study has warned that pregnant women in the country may be at higher risk of stillbirths and miscarriages due to exposure to air pullutants. The study also suggested that meeting India's air quality targets across south Asia may prevent 7 per cent of pregnancy losses in the region.

The study, published in Lancet Planetary Health, is claimed to be the first to quantify the burden of pregnancy loss associated with air pollution in south Asia, which is one of the most PM2.5 polluted regions in the world.

Reportedly, South Asia has the highest burden of pregnancy loss globally. An estimated 349,681 pregnancy losses per year in south Asia were associated with exposure to PM2.5 concentrations that exceeded India's air quality standard (more than 40 ig/m or micrograms per cubic meter air). This number accounted for 7 per cent of annual pregnancy loss in the region from 2000-2016.

"Our findings suggest that poor air quality could be responsible for a considerable burden of pregnancy loss in the region, providing further justification for urgent action to tackle dangerous levels of pollution," IANS quoted lead study author Dr Tao Xue from Peking University in China as saying.

Pregnancy loss more common in northern India

To study the link between air pollution and pregnancy loss in south Asia, the researchers looked at the health data of 34,197 women who had lost a pregnancy, including 27,480 miscarriages and 6,717 stillbirths. The data was collected from household surveys on health from 1998-2016.

Of the pregnancy loss cases, 77 per cent were from India, 12 per cent from Pakistan, and 11 per cent from Bangladesh. Pregnancy loss associated with air pollution was found to be more common in the northern plain regions in India and Pakistan.

The researchers calculated the number of pregnancy losses that may have been caused by PM2.5 in the whole region for the period 2000-16 and the risk for each 10 ig/m increased in PM2.5. Also, they looked at how many pregnancy losses might have been prevented under India's and WHO's air quality standard (40 ig/m and 10 ig/m, respectively).

Each 10 ig/m increased in PM2.5 was estimated to increase a mother's risk of pregnancy loss by 3 per cent. The risk was greater for mothers from rural areas or those who became pregnant at an older age, compared to younger mothers from urban areas, the researchers noted.

Considering the high average levels of air pollution in south Asia, the authors of the study feel that India's air quality standard is a more realistic target level than WHO's safer level.

However, the study was unable to distinguish between natural pregnancy loss and abortions. This may have led to an underestimation of the effect of air pollution on natural pregnancy loss, they pointed out.

Effects of pregnancy loss on women

Losing a pregnancy can have negative mental, physical and economic effects on women. It can increase risk of post-natal depressive disorders, infant mortality during subsequent pregnancy, as well as increase the costs related to pregnancy, such as loss of labour, the researchers said.

Therefore, reducing pregnancy loss may also lead to knock-on improvements in gender equality, asserted Dr Tianjia Guan from the Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

India has 21 most polluted cities in the world

Of the 30 most polluted cities in the world in 2019, 21 were in India, with six in the top ten, according to data compiled in IQAir AirVisual's 2019 World Air Quality Report. Ghaziabad in northern Uttar Pradesh state was ranked the world's most polluted city in 2019, with an average PM 2.5 concentration measurement of 110.2 (which is nine times more than the level regarded as healthy by the US Environmental Protection Agency).

Fine particulate matter, known as PM 2.5, includes microscopic particles that are small enough to enter deep into the lungs and cardiovascular system. Pollutants such as sulfate, nitrates and black carbon are considered PM 2.5. Exposure to such particles can cause lung and heart disorders as well as impair cognitive and immune functions.

As per estimates, air pollution contributes to the premature deaths of 2 million Indians every year. The 51 per cent of India's air pollution is said to be caused by the industrial pollution, 27 per cent by vehicles, 17 per cent by crop burning and 5 per cent by fireworks.