[Preconception counseling--for all].
Preconception counseling is a form of preventive medicine that consists of three main components: risk assessment, health promotion and intervention. As such, it is probably the most important prenatal visit for the prevention of birth defects. All reproductive-age women should be considered at risk for pregnancy and be advised about anticipatory activities that are important in periconception care. This includes folic acid supplementation, rubella and hepatitis B immunization, avoiding tobacco, alcohol and substance abuse, instructions for appropriate nutrition and weight, avoiding teratogens such as organic solvents, pesticides and ionizing radiation, and genetic carrier screening depending on their ethnicity. Women with chronic disease should be evaluated concerning its effect on pregnancy and therapy should be optimized. Also, women with bad obstetric history including preeclampsia, intrauterine fetal death, intrauterine growth restriction, recurrent abortions, preterm deliveries or congenital malformations should be evaluated and counseled prior to another pregnancy.