Health care providers have a unique opportunity to change the behaviors of their patients. Preconception and prenatal care allow for interventions to abate risky behaviors that can affect not only the woman but also her developing fetus. If we can assist the reproductive age woman in modifying her high-risk activities, there will be improved birth outcomes and healthier mothers to care for their offspring. Alcohol and tobacco use, sexually transmitted infections and obesity are the top four modifiable risk factors. This article will address the impact that these behaviors have on women and tools to assist the health care provider in changing these bad habits and promoting healthy pregnancies. The theory of "fetal origins of disease" is emerging as one of the most powerful and compelling reasons to engage our patients before and during their pregnancy. Preventive medicine needs to start in the womb if we want to have the highest impact on healthy adulthood.