Although it could signal pregnancy, early miscarriage, or some nonreproductive disorder, when nausea is related to the Pill, it's the estrogen component that's at fault. For a new Pill user, nausea usually subsides after the first few cycles or remains a nuisance only on the first day of each new cycle.
In addition to switching to a pill with a lower estrogen dose or to a progestinonly method, another possible remedy is taking your pill after a meal. Swallowing a pill before going to sleep has also helped some women.
If the nausea is so bad that you vomit within 1 hour of taking a pill, take another pill from an extra pack. Also, if you missed a pill and are trying to catch up, take the next 2 pills at least 12 hours apart. (For more information see the nearby box on “What To Do When You Miss a Pill.”)