The aim of this study was to investigate prospectively the course of migraine during pregnancy and postpartum. Of all the pregnant women consecutively attending an obstetrics and gynaecology department for a routine first-trimester antenatal check-up, 49 migraine sufferers--two were affected by migraine with aura (MA) and 47 by migraine without aura (MO)--who had experienced at least one attack during the 3 months preceding pregnancy were identified, enrolled in the study and given a headache diary. Subsequent examinations were performed at the end of the second and third trimesters and 1 month after delivery. Migraine was seen to improve in 46.8% of the 47 MO sufferers during the first trimester, in 83.0% during the second and in 87.2% during the third, while complete remission was attained by 10.6%, 53.2%, and 78.7% of the women, respectively. Migraine recurred during the first week after childbirth in 34.0% of the women and during the first month in 55.3%. Certain risk factors for lack of improvement of migraine during pregnancy were identified: the presence of menstrually related migraine before pregnancy was associated with a lack of headache improvement in the first and third trimesters, while second-trimester hyperemesis, and a pathological pregnancy course were associated with a lack of headache improvement in the second trimester. Breast feeding seemed to protect from migraine recurrence during postpartum.