After decades of eugenics campaigns it is known that pregnant women should not smoke and try to avoid passive smoking. Smokers need to quit smoking six months before preparing for pregnancy. If you did not pay attention to smoking in early pregnancy, you need to do the following: 1. Smoking once in a while and the amount is very small, it does not necessarily cause fetal malformation. You can supplement folic acid and other multi-dimensional supplements, eat more fresh vegetables and fruits to prevent birth defects. Do not be too stressed, stress is not good for embryonic development. Pay attention to observe the growth and development of the fetus, to 22-26 weeks of pregnancy, to the hospital to do an ultrasound examination to observe the fetus has no abnormalities. 2, pregnant women smoking is likely to increase the level of carbon monoxide in the blood of the fetus, resulting in fetal hypoxia, pre-eclampsia, stillbirth and increased mortality after birth, the probability of malformation increases. If there is an abnormality, amniocentesis or non-invasive DNA should be done if necessary. Smoking is harmful to health, but for individuals, there is no clear basis to determine the impact on the fetus, nor is it an indication for termination of pregnancy, so pregnant women who have smoked a small amount in the early stages of pregnancy should not be entangled, there are many factors that must affect the development of the fetus, and not just one of them must be malformed, such as the environment, emotions, stress, viruses, etc. The first thing you need to do is to do regular maternity checkups, strengthen monitoring, detect abnormalities, and actively conduct prenatal diagnosis.