A study of previous data suggests the commonly used antidepressant paroxetine may increase the risk of defects by around a quarter. The researchers pooled data from 23 studies which compared women who took paroxetine during the first three months of their pregnancy, with women who did not. It found that the small overall risk of birth defects was 23% higher. This takes the overall risk to approximately 3.69% for women who had taken paroxetine at this time. Based on the type of studies included, we cannot be sure the effect was due to the drug or other factors, such as the woman's depression or other factors linked to it.