Smelling electronic second-hand smoke is harmful to pregnant women, mainly because it may affect the growth and development of the fetus. E-cigarettes are electronic products that mimic cigarettes in that they turn nicotine and other substances into vapor through atomization and other means, and then allow the user to inhale the product. After the atomized nicotine is inhaled, the secondhand smoke that is exhaled also contains nicotine, so electronic secondhand smoke is also harmful to the human body. If a pregnant woman often sniffs electronic second-hand smoke, she may absorb some of the nicotine, which is passive smoking. At this time, the nicotine in secondhand smoke may affect the development of the fetal nervous system, causing fetal growth retardation, and may even lead to fetal developmental deformities. Long-term sniffing of electronic second-hand smoke also increases a woman’s chances of developing respiratory infections, asthma and lung cancer. Therefore, it is recommended that pregnant women stay away from second-hand smoke, quit smoking and drinking, and follow the doctor’s instructions to take obstetrical examinations on time during pregnancy, and if there are any problems, go to the hospital in time for checkups and follow the doctor’s instructions to deal with the treatment.