According to the International Agency for Research on Cancer (IARC) under WHO, cigarette smoking and second-hand smoke are level 1 carcinogens. If you smoke, please quit now.

Women who smoke or inhale second-hand smoke during pregnancy tend to have a high concentration of nicotine or nicotine metabolites such as cotinine residues in their bodies. Growing in the wombs of mothers who smoke will pose negative impacts on the baby's nervous and digestive systems as well as vision developments at various degrees. It increases the risk of miscarriage, birth defect, premature or low birth weight. And these children will be at higher risk of developing leukemia when they grow up.

If the parents are used to smoking indoors or next to their baby, the concentration of nicotine in the baby will be nearly 50 times higher than that of a non-smoker's baby. And even if the parents only smoke at the balcony, the nicotine concentration in their baby is still seven times higher than that of a non-smoking parents' baby.

Smoking or secondhand smoke will not only increase the lead concentration in blood in pregnant women but also pass it through the placenta to the fetus, affecting the fetus's brain development. Nicotine, on the other hand, causes damage to the "neurotransmitter" in the fetus' developing ears, causing hearing problem in children.

Besides, there is a threat of third-handed smoke. The research confirms smoking at home causes high concentration residues of toxic substances in the home, even if it’s a long-extinguished cigarette. These substances will stay in the home in the form of particles that clings on a variety of surfaces (such as furniture like table and chairs, floor, wall, kitchen, bathtub, toilet, etc.). They also can be attached to dust or become volatile toxic compounds that drift into the air after days, weeks, and months. Even if the smoker does not smoke in front of the child, the toxic particles of third-hand smoke will remain for a long time. Hence the person who is in and out of the space exposes to the smoke as well. These substances contain at least 11 highly carcinogenic compounds that cause cognitive impairment in children and increase the risk of asthma, otitis media, and leukemia.