A new study which analyzed over 20 million births uncovered that smoking before and during pregnancy can increase chances of sudden unexpected death for the baby.

The study, published in the American journal Pediatrics, revealed that the risk of death grows by 0.7 for each cigarette smoked.

"Every cigarette counts. And doctors should be having these conversations with their patients and saying, 'Look, you should quit. That's your best odds for decreasing sudden infant death. But if you can't, every cigarette that you can reduce does help,” lead study author Tatiana Anderson, a neuroscientist at the Seattle Children's Research Institute, stated.

"One of the most compelling and most important points that I would take away from the study is that even smoking one or two cigarettes still had an effect on sudden infant death," pulmonologist Dr. Cedric Jamie Rutland, a national spokesman for the American Lung Association, said.

Moreover, researchers brought to light a connection between smoking during pregnancy and a higher risk of asthma, infantile colic, low birth weight, higher levels of serotonin, and childhood obesity.

Secondhand smoke was also found to be dangerous for the fetus, as it increases the risk of low birth weight by 20%.

The study also examined the impact of being a smoker even before pregnancy, detecting that it is almost as hazardous as smoking during pregnancy.

"If you smoke in the three months before pregnancy and quit by the end of the first trimester, you have more than a 50% greater risk of sudden unexpected infant death compared to nonsmokers," Anderson pointed out.

"Women who are planning on getting pregnant and are smokers should quit well before they even try to get pregnant, because smoking in the first three months before you get pregnant can have a detrimental effect," she added.