The pregnant or breast-feeding patient presents a number of unique management problems for oral health care providers. Clinicians are responsible for providing safe and effective care for the mother, while also considering the safety of the fetus or newborn. They must consider the effects of medications, which may be distributed from the maternal plasma through the placenta to the fetus, or to breast milk, exposing the nursing infant to potentially dangerous concentrations. In addition, a number of maternal oral changes, requiring the attention of oral health care providers, may be observed as a consequence of the multiple physiologic changes associated with pregnancy. In view of the dual responsibility that oral health care providers face in treating the pregnant or breast-feeding patient, understanding the physiology of pregnancy, fetal development, potential oral complications of pregnancy, and the effects that dental intervention may have on the woman, her fetus, or her neonate are imperative. Keywords: oral hygiene, periodontitis, pregnancy, pregnancy gingivitis, pregnancy tumor, dental care/management, drugs