There is increasing recognition that ADHD is a common condition, not only in children and teenagers but also in adults. This has led to a rapid rise in the number of women of childbearing age who are being treated for this condition. Against the background of concerns about the use of medication of any kind during pregnancy and breastfeeding, it is remarkable that there is so little information available on the effects of ADHD medication on the fetus and newborn. The impulsivity associated with ADHD might lead to an increased rate of unplanned pregnancy. Although treating ADHD during pregnancy and lactation might have negative effects on the baby, suspension of treatment or inadequate treatment could also place both mother and baby at risk. Pharmacodynamic and pharmacokinetic changes during pregnancy could affect both the efficacy and the concentration of medication. Again, there is almost no guidance available. The US Food and Drug Administration has classified ADHD medications as being "pregnancy category C", implying that there is insufficient information to confirm either harm or lack of harm. From the limited information that has been published, it would appear that the risk of fetal malformation, at least with methylphenidate, is very low and that the amounts of medication excreted in breast milk and consumed by the infant are very small. Three questions that both clinicians and patients are likely to ask are the following. Should ADHD medication be stopped before, during or after pregnancy, or should it be continued throughout? Should ADHD medication doses be adjusted during the course of the pregnancy or after delivery? Should breastfeeding be encouraged or discouraged? Discontinuing ADHD treatment could put both mother and baby at risk. This has to be balanced against the possible risks to the baby of continuing treatment. Although the data remain inadequate, the risk of the latter appears to be quite small, at least for methylphenidate. However, there is recent evidence that the rates of fetal loss both through abortion and through miscarriage are increased with methylphenidate. Discussions about ADHD treatment with women of childbearing age should be balanced, open and honest, acknowledging the lack of information on the possible risks to the offspring of continuing treatment, while also drawing attention to the possible risks to both mother and child of discontinuing treatment.