Every one in five Indian women has polycystic ovary syndrome (PCOS) which is also a common causative factor for infertility. In almost 75% PCOS women, anovulation is the major leading cause of infertility. PCOS disorder is not just limited to local ovarian dysfunction but encompasses of complex functional variation of the entire reproductive system. Notably, PCOS is an endocrine-metabolic condition which affects reproductive functions by triggering an insulin-resistant state.4 Almost 80% women with PCOS have central obesity and approximately 30–40% lean PCOS women have an occurrence of hyperinsulinemia and insulin resistance.
Pharmacological therapies involving insulin sensitizers counteract hormonal signs due to the pathophysiological link between insulin resistance and PCOS alterations. Among the insulin sensitizers, major problems with metformin are gastrointestinal and metabolic complications, which may affect its drug compliance.
Myoinositol is the most extensively studied inositol and is a novel addition to the drug armamentarium of insulin sensitizers. A randomized controlled trial compared combination of metformin (1500 mg/day) and myoinositol (4 g/day) with myoinositol (2 gm BD) alone for six months in 130 infertile PCOS women.
Both treatment groups demonstrated almost similar improvement in metabolic and hormonal parameters after 3 months of treatment period. Clinical pregnancy rate was 42% with combination of metformin and myoinositol therapy and 45.5% with myoinositol alone (p > 0.05) after 6 months of treatment period (Figure 1).
Conceived patients had a documented gestational sac and fetal cardiac activity with no biochemical/ectopic pregnancies. Ongoing pregnancy and live birth rate were 40% in combination of metformin and myoinositol and 41.8% in myoinositol alone (p = 0.849). Among women with or without family history of diabetes, conception rate was 46.7% and 40% respectively (p = .662) with combination of metformin and myoinositol. On the other hand, myoinositol monotherapy group showed 38.9% and 48.6% conception rates (p = .495) in women with or without family history of diabetes respectively.2
Combination of metformin and myoinositol (84.2%) reported significantly higher adverse events as compared to myoinositol alone (18.7%). Gastrointestinal side-effects were significantly higher with the combination of metformin and myoinositol therapy.2
This study revealed similar improvement in body mass index (BMI), menstrual irregularities, hormonal and metabolic outcomes with both myoinositol monotherapy or along with metformin. However, it did not document any additional benefit of combining metformin and myoinositol therapy other than increasing side effects due to metformin.
Conclusion:
Myoinositol alone should be preferred as an insulin sensitizer over combination of metformin and myoinositol to improve metabolic, hormonal and reproductive outcome in infertile PCOS women.2 Myoinositol monotherapy may prevent the need for metformin, which is associated with gastrointestinal side effects in infertile PCOS women.