Pregnancy in patients with Parkinson's disease (PD) is a rare occurrence. Previous reports based on retrospective analysis suggest that pregnancy may have a deleterious effect on PD. We describe the effects of pregnancy on the symptomatology of a 33-year-old woman with PD using quantitative neurologic and quality-of-life scales prepartum, intrapartum, and postpartum. During her pregnancy, she was only treated with carbidopa/levodopa. The pregnancy resulted in a normal full-term vaginal delivery of a healthy infant. Significant worsening of this patient's motor symptoms occurred during pregnancy without return to baseline at 15 months postpartum. Pregnancy may exacerbate PD and may have a long-term negative impact on the course of the illness. This report may assist physicians in the counseling of patients with young-onset PD who wish to consider pregnancy.