Effects of metformin in reducing insulin resistance and reversing gonadotrophin levels (LH, FSH) followed by ovulation induction in infertile women with polycystic ovarian syndrome

Abstract

Objectives: To evaluate the effectiveness of metformin in reducing insulin resistance, reversing the LH:FSH and followed by ovulation induction in infertile Bangladeshi patients with polycystic ovarian syndrome (PCOS).

Materials and methods: Cases were infertile patients with PCOS (n=35, age range – 18-35 years/Mean, age±SD – 25.68±3.81 years, infertility – 1.5-10.0 years, Mean±SD – 4.12± 1.21 years) obtained from OG-OPD at MCW&H, Dhaka. Infertile Bangladeshi couples without PCOS (n=30) were included as controls. After fasting blood samples were collected at inclusion (PCOS-Iº), metformin was prescribed (850 mg bd) and they were followed up after 2 months when fasting blood samples were taken again (PCOS-IIº). Blood levels of glucose, insulin, insulin resistance (HOMA-IR), LH, FSH and LH:FSH were measured by standard laboratory methods. The patients were then given letrozole (aromatase inhibitor) (5 mg daily for 5 days from 2nd day of cycle) and were continued for 3 consecutive cycles for pregnancy.

Results: Raised levels of insulin and HOMA-IR in PCOS-Iº were reduced significantly by metformin treatment (PCOS-Iº vs PCOS-IIº P<0.001), but not to the control levels. Similarly, the elevated levels of LH, FSH and LH:FSH were lowered significantly (PCOS-Iº vs PCOS-IIº P<0.001), but again not to the full extent of control levels. Only 12/35, i.e. 34.28% patients became pregnant after 3 months of letrozole treatment. Of the 12 (34.28%) pregnancy positive patients, 5 (14.28%) and 7 (20%) were obese and non-obese respectively which was not statistically different (P>0.25).

Conclusions: In 34.28% of the PCOS patients, insulin resistance and LH:FSH could be corrected and a successful conception was achieved by letrozole. In rest of the cases some other factors may be involved which could not be addressed by letrozole alone.

Key words: PCOS; metformin; insulin resistance; FSH; LH.

DOI: http://dx.doi.org/10.4038/sljog.v33i3.4017  

Sri Lanka Journal of Obstetrics and Gynaecology 2011; 33: 98-103