During pregnancy, two thirds of women stop having migraine headaches.  However, one third continues to have them, and sometimes even worsen during pregnancy.   As a general rule, only acetaminophen (Tylenol) is considered safe, but for most migraine sufferers it is completely ineffective.  Codeine is also benign, but it also either does not work or causes side effects, such as nausea and sedation.  Triptans, such as sumatriptan (Imitrex), rizatriptan (Maxalt), and other are very effective for migraines, but are not proven to be as safe.  Pregnancy registries in the US have information on over 1,500 women who took a triptan during pregnancy and so far the drugs look safe for the baby.  A new study from Norway in the February issue of Headache reports on another 1,535 women who took triptans during pregnancy and compared them to 68,000 women who did not.  This study also found no increased risk of congenital malformation, even if triptans were taken in the first trimester.  Women who took triptans in the second and third trimester also had healthy babies, but they had a slightly increased risk of atonic uterus and bleeding during labor.