Pain/swelling at injection site, breast tenderness, headache, weight gain/loss, acne, nausea, increased body/facial hair, loss of scalp hair, drowsiness, or dizziness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor immediately if any of these unlikely but serious side effects occur: unusual vaginal bleeding/discharge (e.g., breakthrough bleeding, spotting), stopped menstrual periods (amenorrhea), breast lumps, swelling of the ankles/feet, mental/mood changes (e.g., depression, nervousness), dark patches on the skin/face, frequent/painful urination, dark urine, yellowing eyes/skin, stomach/abdominal pain, persistent nausea/vomiting. This drug may rarely cause blood clots. Seek immediate medical attention if any of these rare but very serious side effects occur: chest/jaw/left arm pain, weakness on one side of the body, slurred speech, vision changes (e.g., blurred/double vision, loss of vision), confusion, pain/redness/swelling of arms or legs, trouble breathing, sudden severe headache, fainting. A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.