This Guide provides comprehensive, national guidance for the optimal management of pregnant and parenting women with OUD and their infants based on the recommendations of experts reviewing the limited evidence available for this population as of 2017. In the past, only one option was available for OUD treatment in pregnant women. Today, more options are available, so healthcare professionals need to provide more education to their patients and obtain their detailed informed consent to ensure decision-making is shared between the pregnant woman or new mother and the healthcare professional. This Guide will help healthcare professionals and patients determine the most clinically appropriate action for a particular circumstance, with the expectation that the healthcare professionals will make individualized treatment decisions. A cornerstone of the Guide is that a healthy pregnancy results in a healthy infant and mother. The Guide recognizes the mother and infant as a dyad, and the recommendations are provided in light of what actions will optimize the outcomes for the mother-infant dyad as a whole, with guidance provided from preconception to several months postpartum and for the first few years of infant development.