Data in the literature show that migraine tends to improve during pregnancy in most migrainous women. The aim of this Internet survey was to obtain the most likely cross section of the situation in the general population with respect to the presence and course of migraine in pregnancy. All women who participated were asked to answer questions pertaining to their history of pregnancy and headache. One thousand and eighteen women participated in the survey; only 775 met the eligibility criteria for inclusion. One hundred and ninety-five women (25.2 %) reported having had a headache only before pregnancy, 425 (54.8 %) before and during pregnancy, and 155 (20.0 %) only during pregnancy. Women suffering from headache before and/or during pregnancy were much more likely to have headaches with more migrainous features at the ID Migraine Screener test when compared to women whose headache began during pregnancy. “Definite migraines” were 277/620 (44.7 %) and 26/155 (16.8 %), respectively, in the two groups (p < 0.0001). Among the 620 females that suffered from headache before pregnancy, 375 (60.5 %) improved, 195 (31.5 %) showed complete resolution of the disorder, and 180 (29.0 %) had a reduction in headache frequency. Moreover, the multinomial logistic model (with headache pattern as dependent variable) proved fetal presentation as significant (p = 0.0042). Women with “new headache” (No/Yes pattern) had an OR (95 % CI) of 1.9 (1.2–3.0) of breech presentation at delivery versus those with a stable pattern of headache (Yes/Yes). Finally, women with not recent pregnancy stated they suffered from headache less than the women with recent pregnancy.