In the United States, about 8% of all women who are pregnant smoke cigarettes, and another roughly 4% report using electronic cigarettes or vapes. To learn more about the dangers of smoking Smoking and vaping during pregnancy increase the risk of preterm birth support is available to help you quit. Smoking during pregnancy is the biggest modifiable risk factor for preterm birth. Quitting Health Effects of Maternal Exposure to Thirdhand Chemical Residue from Vape Aerosols Persist Long After Infancy Thirdhand Smoke Resource Center Can You Vape While Pregnant? Evidence Based Guide