A new Cochrane Review comparing the two most common treatments used in the long-term medical management of the condition polycystic ovary syndrome (PCOS), the oral contraceptive pill (OCP) or metformin, shows individualization of treatment provides the best result in tackling the unique needs of women with PCOS.

Senior lead researcher Dr Michael Costello, a fertility specialist at IVFAustralia, said the research findings are empowering for some women with PCOS.

The research shows the best outcomes can be achieved when treatment is tailored to the symptoms, and the evidence demonstrates the best combinations of medicines to treat PCOS, but more research is still required, especially in adolescents as there is very little data.

“Women with PCOS experience different problems, some will have excess hair growth (hirsutism) , some will experience acne, problems with fertility, irregular menstrual cycles or weight gain,” said Dr Costello.

Dr Costello said if the main concern for the patient with PCOS is menstrual regulation then the OCP should be used rather than metformin.

“For women who experience hirsutism symptoms, the OCP is more effective than metformin whilst a combination of the OCP and metformin is more effective than either the OCP or metformin on its own.

“What is concerning, there is very limited research data in adolescent women with PCOS, so in terms of the evidence, it’s uncertain if adolescent women should be taking the OCP in preference to metformin or vice versa, and more good quality research needs to be done.

“In terms of side-effects, the OCP has less gastro-intestinal side-effects (i.e. nausea, vomiting, diarrhea) compared to metformin but metformin has less other side-effects such as breast tenderness and bloating.

“Throughout the review, the patients were sub grouped according to their mean BMI e.g. normal, over weight and obese, to see if the effect between the OCP and metformin is different. The results show that in many cases, the effects of Metformin versus the OCP are different depending on the woman’s BMI.

“A lot of people think that if you go on metformin rather than the OCP then you will lose weight, but when we looked at all the studies during the systemic review, they showed that metformin did not reduce weight compared to the OCP,” said Dr Costello.

In 2018, Dr Michael Costello co-authored the first ever evidence based international guidelines on PCOS, chairing the fertility section alongside fertility experts on PCOS from around the world.

“The research findings of this review are consistent with and support the recommendations of these recently published international guidelines in PCOS, which is re-assuring,” said Dr Costello.

Dr Costello said this latest Cochrane systematic review on PCOS will also now help inform the future international guidelines on PCOS to be updated in several years time.

“The important thing about Cochrane systematic reviews is that they help inform clinical practice as opposed to one single small trial which may or may not show any difference between the two therapies.

“The review also highlights what future research in PCOS needs to be undertaken, especially in adolescent women as there is very little data. This includes performing more high quality research and sub grouping the patients according to BMI, as the research has shown that BMI may impact on the effect of these two treatments.

“The majority of women with PCOS have insulin resistance and as such metformin, which helps reduce insulin resistance,  was initially heralded in 1994 as the promising new treatment for women with PCOS that would replace the OCP. But after all these years, it’s not the panacea treatment everyone was hoping it would be. However the evidence to date shows that there are selective indications for the use of metformin in women with PCOS but further high quality research needs to be done,” said Dr Costello.