No smoking or drinking at all throughout pregnancy — and no one else in the house should smoke either

There’s no cost at all; in fact, it saves money on cigarettes and alcohol. The real challenge is getting everyone living in the same house to quit alongside the pregnant woman.

The US Centers for Disease Control and Prevention’s framing: smoking in pregnancy can leave a baby “born too small, even if full term” and “may lead to preterm birth.” It “doubles the risk of abnormal bleeding during pregnancy and delivery.” It raises the risk of birth defects such as cleft lip and cleft palate. It also “can damage a baby’s developing lungs and brain,” and “the damage can last into childhood.” Infants of mothers who smoked in pregnancy, and infants exposed to smoke after birth, have a higher risk of sudden infant death syndrome. Official advice is to “quit smoking before getting pregnant if you can, but quitting is still helpful if you are already pregnant” and “it is never too late to quit.” On alcohol, the CDC says there is “no known safe amount of alcohol use during pregnancy,” and no stage of pregnancy when drinking is safe. The baby’s brain develops through the whole pregnancy, so alcohol contact at any time may cause harm

Centers for Disease Control and Prevention. Smoking During Pregnancy. https://www.cdc.gov/tobacco/campaign/tips/diseases/pregnancy.html；Centers for Disease Control and Prevention. About Alcohol Use During Pregnancy. https://www.cdc.gov/alcohol-pregnancy/about/index.html

Secondhand smoke from anyone smoking indoors is just as harmful to the fetus as direct smoking. Therefore, this rule applies to the whole household, not just the pregnant woman. The same principle holds true for alcohol: there is no known safe level of alcohol consumption during pregnancy, so the safest approach is to avoid it entirely. The impact of smoking and drinking on the health of adults themselves is covered in Section 2.