Scientists at the Tianjin Medical University and several other research institutions in China, Canada, and the United States, linked passive smoking with the risk of developing Gestational diabetes also known as diabetes of pregnancy. Their study, reported on in September of 2016 in the Diabetes Metabolism Research and Review, included 12,786 pregnant women. All were routinely tested for high blood sugar readings …

  • 8331 women exposed to passive smoking, 7.8 percent developed diabetes during their pregnancy.
  • pregnant women not exposed developed the condition in 6.3 percent of cases.
  • the pregnant women exposed to smoke had a 29 percent higher risk of developing Gestational diabetes than did the unexposed women.
  • obese women exposed to secondhand smoke had more than three times the risk of developing diabetes during their pregnancy compared to non-obese women who had not been exposed to smoke.

From these results, the researchers concluded obesity and passive tobacco smoking worked together synergistically to raise the pregnant mother's risk of developing Gestational diabetes.

According to the American Journal of Obstetrics and Gynecology, July 2016, birth defects are also linked to passive smoking. Researchers at the Texas Department of State Health Services and various other research institutions in the United States examined information from the National Birth Defects Prevention Study. The study includes many sites keeping records on birth defects.

Over the period from 1997 to 2009 researchers compared cases of birth defects with 10,200 normal births. They included forty-four types of birth defects and mothers who had been exposed to secondhand smoke between one month before conception through the first three months of pregnancy. The risk of several types of birth defects was greater in mothers who had experienced second-hand smoke …

  • anencephaly: missing much of the brain – a 66 percent higher risk,
  • spina bifida: inadequately formed spinal cord) – a 49 percent greater risk,
  • cleft or split lip only – a 41 percent higher risk,
  • cleft lip with or without cleft palate – a 24 percent increased risk,
  • cleft palate only – a 31 percent greater risk,
  • lack of kidneys – a 99 percent higher risk,
  • limbs outside the bag of water – a 66 percent increased risk,
  • a hole in the wall separating the left and right top chambers, or atria of the heart – a 37 percent greater risk.

The investigators concluded more studies of secondhand smoke and birth defects are warranted. They caution the number of birth defects studied could have led to some associations purely by chance. Pregnant mothers might also not be able to recall their exposure to secondhand smoke correctly as well. On the other hand, we know passive smoking is not okay for any of us and causes less oxygen to go to the fetus, so avoiding smoke is all to the good.