Is methylphenidate safe to take during lactation (breastfeeding)?

When one of my outpatients who has attention-deficit/ hyperactivity disorder (ADHD) started to plan a pregnancy, I recommended that she first taper off the methylphenidate extended-release (Concerta®) that she was on before stopping her contraception. With support from her family, she did OK during the pregnancy. But she and I agreed that it could be…