Most information we get about safety in pregnancy often comes from practical experience with the medicine over time. Often, when a medicine has been in wide use for many years without causing adverse effects on pregnancies, we can conclude that it is not harmful. Information will also come from women who have been accidentally exposed to a medicine during pregnancy and from animal studies. So some medicines are known to be safe while others are known to be definately harmful. But in a large number of cases there isn't the firm evidence to conclude safety or risk. This applies to all medicines, be they prescription only or over-the-counter. Taking any medicine during pregnancy is all about weighing up the pros and cons. The decision should, ideally, be made by your doctor, who will be able to weigh up the benefits of a particular medicine to the mother against the risks of that same medicine to the baby. If the benefits outweigh the risks, then the