Polycystic ovaries is one of the most common endocrinological disorder of the ovaries, commonly seen among the women belonging to the reproductive age group with prevalence about 5 - 10 % 
. Insulin sensitising drugs are used in the treatment of PCOS and Metformin was the first insulin sensitising drug and it showed a reduction in circulating androgen level, significant reduction in the body weight and improvement in menstrual regularity 
. Inositol phosphoglycan molecule is known to have a role in activating enzymes that control glucose metabolism [8-10]
. Eventhough D-Chiro-inositol was the primary form studied initially in PCOS, the main focus of many recent studies has turned on myo-inositol 
. The aim of our study was to compare the clinical outcome of long- term treatment of women with polycystic ovarian syndrome with myoinositol and metformin and to monitor the changes in bio-chemical parameters following treatment.
Methodology: This ethical committee approved study was done in the Department of Obstetrics and Gynaecology, Rajah Muthiah Medical College and Hospital, Chidambaram for the duration of two years from June 2018 to October 2020. A random hundred women (Married/un married) between the age of 18 to 40 years with signs and symptoms of PCOS (According to Rotterdam Criteria) attending the OPD were included in the study after obtaining consent from them. A detailed history regarding the menstrual cycle, gynaecological complaints, hirsuitism, acne, acanthosis nigricans were dealt in detail followed by anthropometric measurements, general and systemic examination. All the patients were subjected to pelvis ultrasonography. They were divided into two groups (group 1 and group 2) each group consisting of fifty members each. A fasting venous blood sample was taken on day two of menstruation and sent for biochemical investigations. Group 1 patients were treated with Metformin 500mg daily for 6 months. Group 2 patients were treated with Myoinositol 1gm with folic acid daily for 6 months. These patients were called after 6 months and again subjected to anthropometric measurements followed by general and systemic examination. Blood sample was taken for investigations and subjected for ultrasonography. The side effects of each group was noted. The efficacy of Metformin Vs Myoinositol, in the PCOS patients, were compared and statistically analysed.
Results: Both the treatment groups i.e. Myoinositol and metformin were found to be almost equally effective in improving biochemical profile. In our study glucose-insulin ratio improved significantly in both groups but more in Group 1 as compared with Group 2. Both the groups showed improvement in the menstrual pattern with group 1 showing comparatively better results. There was no significant decrease in body weight and BMI. Acanthosis nigirians was very much reduced after treatment with metformin (Group 1), whereas there was no significant improvement in Group 2. Metformin therapy lead to a reduction in ovarian volume. Though both groups reported improvement in biochemical parameters, metformin group showed significant decrease in free testosterone level as compared with myoinositol group. Group 1 showed significant decrease in insulin resistance as compared with Group 2. In our study the reduction in the mean modified Ferriman Gallwey score (mFG) of hirsuitism was statistically significant in both the groups, but on comparing the two groups, group 1 had a significant reduction than group 2.
Conclusion: Metformin and myo-inositol substantially enhanced insulin sensitivity in PCOS women. Both the treatment groups i.e. Myoinositol and metformin were found to be almost equally effective in improving biochemical profile. However metformin performed better than myoinositol in improving menstrual irregularities, BMI, insulin resistance, biochemical profile and clinical features. Hence, Metformin as an insulin sensitizer is effective in the treatment of PCOS as first line therapy in PCOS. Myo-inositol can be a new addition in the armamentarium for the treatment of PCOS with comparable efficacy.