Headaches during pregnancy in women with a prior history of menstrual headaches.

OBJECTIVE To evaluate the presence of menstrual headaches prior to pregnancy according to the International Headache Society (IHS) classification criteria, 2004, and also study the outcome (frequency and intensity) of these pre-existing headaches during the gestational trimesters. METHOD This study involved 1,101 pregnant women (12 to 45 years old). A semi-structured questionnaire was used to interview the women during the first, second and third gestational trimesters as well as after delivery. All the interviews were conducted by one of the researchers by applying the IHS Classification (IHSC-2004). RESULTS A 1,029 women out of the 1,101 women interviewed presented headaches prior to gestation, which made it possible to study headaches in 993 women during the gestational trimesters. Menstrually related headaches were presented by 360 of the 993 women. Migraine was reported by 332/360 women (92.22%) with menstrual headaches and 516/633 women (81.51%) without menstrual headaches, respectively, prior to gestation. The majority of the women with menstrual migraine presented a headache improvement or disappearance during gestation (62.22% during the first trimester; 74.17% during the second trimester; 77.78% during the third trimester). CONCLUSION Most of the pregnant women with menstrual or non-menstrual headaches prior to gestation presented migraine, which either improved or disappeared during pregnancy. Women who suffered from non-menstrual headaches improved during pregnancy but not as much as women with menstrual headaches.