It should not to be used in pregnancy, breastfeeding or children, but accidental usage in these situations unlikely to be harmful. It should be used with caution in patients with epilepsy, migraine, heart failure, high blood pressure, kidney disease, diabetes, porphyria or uterine disease. It should be totally avoided in patients with liver disease, breast or genital cancer, or a history of blood clots.
Side effects may commonly include abnormal uterine bleeding, vaginal thrush, nausea, fluid retention, weight gain and breast tenderness. Unusual side effects may include a rash, blurred vision, vomiting, bloating, intestinal cramps and pigmentation of the skin on the face. Severe but rare side effects include blood clots, calf or chest pain and yellow skin (jaundice).