Over fifty per cent of pregnant women in developing countries are exposed to second hand smoke, according to a study which found that such exposure causes about 17,000 still births every year in Pakistan alone.
Exposure to second hand smoke during pregnancy increases the risk of stillbirth, congenital malformations, low birth-weight and respiratory illnesses.
However, little is known about the extent of second hand smoke exposure during pregnancy.
Researchers from University of York in the UK looked at the number of pregnancies alongside smoking exposure data in 30 developing countries from 2008 to 2013.
The analysis revealed that in Armenia, Indonesia, Jordan, Bangladesh and Nepal more than 50 per cent of pregnant women reported exposure to household second hand smoke.
According to the study published in the journal BMJ Tobacco Control, this led to over 10,000 still births in Indonesia alone. Over 40 per cent of all pregnant women in Pakistan are exposed to second hand smoke - causing 17,000 still births every year
In Pakistan only one per cent of still births are attributed to women actively smoking during pregnancy, but for second hand smoke the figure is seven per cent, largely due to the high numbers of pregnant women exposed to tobacco smoke in the home.
In five of the 30 countries, household second hand smoke exposure was twice as common as active smoking.
Researchers said it was predominately male smokers exposing women to second hand smoke.
"This is the first study which provides national estimates for 30 developing countries on second hand smoke exposure in pregnancy and it reveals a huge problem, a problem which is not being addressed," said Kamran Siddiqi, from the University of York.
"We have shown for the first time that second hand smoke during pregnancy is far more common than active smoking in developing countries, accounting for more still births than active smoking," said Siddiqi.
"Protecting pregnant women from second hand smoke exposure should be a key strategy to improve maternal and child health," he said.
Researchers said that the results are based on self-reported surveys and could be subject to underestimation. Further work is needed to develop effective interventions to reduce household exposure to second hand smoke.
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