Comparing the Use of Dienogest and Combined Oral Contraceptive Pills (Microgynon) to Reduce the Risk of Recurrence of Endometriotic Cyst After Conservative Surgery

A Prospective, Randomized Controlled Trial Comparing the Use of Dienogest and Combined Oral Contraceptive Pills (Microgynon) to Reduce the Risk of Recurrence of Endometriotic Cyst After Conservative Surgery

The purpose of the study is to compare the recurrence of endometriotic cyst in patients taking Dienogest or Microgynon after conservative surgery.

Inclusion Criteria:

• Good general health
• Older than the age of legal consent (i.e. 18 years old)
• Sonographic diagnosis of ovarian endometrioma with diameter at least 4cm on 2 separate scans at least 6 weeks apart
• No contraindication to use of progesterone or combined oral contraceptive pills
• Not attempting to conceive either at the time of study entry or for at least 2 years after surgery
• Willing and able to participate after the study has been explained

Exclusion Criteria:

• Operative findings not suggestive of endometriotic cyst
• Contraindications to progestogens or oral contraceptive pills
• Unwillingness to tolerate menstrual irregularity
• Planning pregnancy within 2 years of study
• Cannot understand English, Cantonese or Putonghua