list of side effects from netdoctor:
Very common (affect more than 1 in 10 people)
Changes in menstrual bleeding, eg irregular bleeding, bleeding heavier or lighter, bleeding more or less frequent, continuous, or prolonged bleeding, or bleeding stopped altogether.
Headache.
Vaginal infections.
Acne.
Weight gain.
Breast tenderness or pain.
Common (affect between 1 in 10 and 1 in 100 people)
Irritation, bruising, pain or itching at site of implant.
Fatigue.
Increased appetite.
Depressed mood.
Mood swings.
Nervousness.
Decreased sex drive.
Dizziness.
Hot flushes.
Abdominal pain.
Feeling sick.
Wind (flatulence).
Hair loss.
Painful periods.
Ovarian cysts.
Weight loss.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
Urinary tract infection.
Migraine.
Anxiety.
Difficulty sleeping (insomnia).
Sleepiness.
Vomiting.
Constipation.
Diarrhoea.
Increased hair growth.
Vaginal discharge or itching.
Aching muscles or joints.
Breast enlargement.
Fluid retention (oedema).
Rash or itching.
Rare (affect between 1 in 1000 and 1 in 10,000 people)
Scarring or abscess at site of implant.
Rise in blood pressure.