Preparation for pregnancy includes examinations to determine the health status of the parents, identify and treat latent and chronic infections, and other diseases that may adversely affect the fetus and the mother's body. The harmful effects of alcohol, drugs, and tobacco smoke should be excluded at least 3 months before conception and throughout pregnancy. Even before conception, it is very important to prevent vitamin and mineral deficiencies. This is especially true for iodine, folic acid, and iron. The lack of these substances in the diet of future parents, especially the mother, can lead to fetal malformations at such an early stage of pregnancy, when the mother may not even be aware of it.