Some of the side effects of Diane
35 are menstruation-like abdominal cramps and water retention. This may be the cause of your feeling of heaviness in the stomach. These side effects are more prominent initially when you start taking the medication and they usually subside as your body gets used to the drug.
Do inform your doctor if the symptoms persist beyond 3 months or if you experience pain, swelling or tenderness in the abdomen.
Hope I have answered your query.