Disclaimer: I AM NOT A DOCTOR, Talk to your OB before taking anything.
My co-worker is due two weeks after me and we are both pre-pregnancy migraine sufferes. During our pregnancies we have both been suffering from severe headaches and migraines - mostly weather related (since we seemed to have skipped over the spring and summer seasons over here in Canada and landed back in fall).
Anway - her sister is a pharmacist and b/c Tylenol isn't doing a damn thing for either of us (as is the case with a lot of you ladies as well) she started doing some research about Ibuprofen (advil/motrin). Turns out the medical surveys say that it is only relatively unsafe to take Ibuprofen in your first trimester and last 2 weeks of pregnancy.
I am currently skulking around the internet to find more info before I pop an Advil to get rid of the monster in my head - but I thought I would share this info in the meantime as I originally thought it was completely off-limits. For those of you really suffering it's at least worth talking to the OB about at the next appt.