I went to see my Ob yesterday, exactly for this reason.
My headaches have been crippling. This is my second pregnancy and I did not get any in my first!
My OB, checked my blood pressure to make sure that was not a reason for the headaches.
He suggested 2 panadol, if that did not work 4 hours later, 2 panadeine. He also suggested Panadol forte and Mysindol could be used as well. He also said cold packs should work well too.
He seems to think that it is caused by the extra blood flow, during pregnancy.