In Reply.—The problems that Dr Maynard has identified are largely inescapable when studying a population that has little or no contact with the medical system prior to delivery.
We entirely agree that "repeated questioning and repeated drug testing throughout the course of pregnancy" might have enabled us to identify and quantitate maternal drug use more accurately. However, the majority of the women using drugs in this study had little or no prenatal care. While studies of women using drugs who receive good prenatal care may address this limitation of our study, we suspect that there may be some substantial differences between the population of women who seek routine prenatal care and those who do not.
Given the fact that patterns of drug use are likely to change during the duration of pregnancy and the lack of adequate markers for quantitating drug use, we could not determine the quantity of drugs used