This is one of the most important aspects as calorie restriction is the key to weight loss. Many researchers have suggested different types of diets like the Atkins diet, high protein diet, and no carbohydrate diet, but without much results. There is increased evidence in favor of diets utilizing food having reduced glycemic load and high glycemic index. In the absence of good level of evidence, calorie restriction of 500 kcal/day is presently recommended for PCOS female [8]. An overall decrease in calorie intake is more important than any specific composition. Lifestyle treatment leads to weight loss, decrease in free androgen, abdominal obesity, and surrogate marker of insulin resistance and an improved quality of life in PCOS.

Daily exercise is one of the key factors for weight loss. Exercise reduces the risk of having DM type 2 and cardiovascular disease in a PCOS. Moderate activity that is sustained is better than vigorous activity that is not regular. The aim is to develop a healthy lifestyle that is continuously followed. Moran et al. [10] described that climbing 8000 steps a day along with change in diet pattern decreases the testosterone level by 57 %. Insufficient physical activity is one of the reasons obese PCOS women put on weight. Patients who are morbidly obese should be advised rigorous weight loss under supervision because of possible orthopedic and cardiovascular risk involved in unsupervised exercise. Hoeger et al. [11] advised weekly exercise for 150 min/week along with dietary restriction with the goal of 5–7 % weight loss leading to decrease in SHBG and insulin resistance.

Drugs are used either to suppress appetite or those which have an antiobesity effect. Antiobesity drugs include orlistat which acts by decreasing intestinal absorption of fat [12]. Appetite suppressant like sibutramine acts by decreasing the appetite and has dose-dependent action [13]. Statins act by inhibiting HMG-CoA reductase enzyme, which is the rate-limiting step in cholesterol pathway. There is decrease in levels of testosterone along with dyslipidemia and therefore PCOS patients are at risk for developing diabetes and cardiovascular disorder. They are teratogenic in pregnancy. According to Cochrane (2011), statins are effective in reducing serum androgen levels and LDL, but statins are not effective in reducing fasting insulin or insulin resistance. There is no good evidence available on the long-term use of statins alone or in combination for management of PCOS [14].

Bariatric surgery can be offered to morbidly obese women with BMI of >35 kg/m² [15]. With surgery the weight loss is maintained. The pregnancy per se becomes high risk, as there is increased chance of IUGR and decreased weight gain in these females.

Metformin is a biguanide, oral insulin-sensitizing agent used in the treatment for diabetes mellitus type 2. It acts by increasing the peripheral uptake of glucose in the muscle and intestine [16], decreases hepatic glucose uptake, and inhibits lipolysis, thereby decreasing the circulating levels of free fatty acids and increasing the insulin sensitivity. It thus helps in decreasing weight and LDL cholesterol. The tablet is available in both regular and sustained release form starting with a minimum dose of 500 mg per day along with meals to a maximum level of 1500–2000 mg per day [3].

Metformin should be given to women having impaired glucose tolerance, diabetes mellitus type 2, and severe insulin resistance. It is also given where there is metabolic syndrome like dyslipidemia and central obesity. In adolescent PCOS girls, it has been shown that metformin treatment can result in decrease in hyperandrogenemia and hyperinsulinemia. Cochrane analysis (2013) has found that metformin decreases the incidence of OHSS in females undergoing ovulation induction, but it does not increase the chance of having a live birth [17]. The drug is prescribed only in patients having glucose intolerance [8]. Also in cases of ovulation induction, there is no benefit of prescribing metformin alone or with clomiphene citrate except in cases where patient has BMI [18] of >35 kg/m².

Minor side effects like nausea, vomiting, diarrhea, bloating, flatulence, and metallic taste occur in 20 % of patients. It resolves if drug is taken with food. Since this effect is dose dependent, the dose of metformin should be increased in an incremental fashion. If discomfort is significant, the drug should be discontinued. There may be weight loss associated with the nausea and vomiting accompanying the drug. Megaloblastic anemia may occur in some patients because of subnormal B₁₂ levels. Before starting metformin, renal and liver functions should be tested.

Hypoglycemia does not occur with metformin in euglycemic patients. It may be seen in special cases where there is deficient caloric intake and concomitant use with sulfonylureas and strenuous exercise is not compensated with adequate intake or excessive alcohol consumption. It is contraindicated in renal disease and myocardial infarction. Drug interaction occurs with diuretics, oral contraceptives, and phenytoin.

Metformin induces regular cycles in some women treated for 4–6 months. It improved ovulation, hirsutism, hyperandrogenemia, and insulin resistance. Lowering of fasting insulin levels is seen in 2–3 months. A repeat test is required only after this period. If amenorrhea persists, clomiphene or rosiglitazone is added. Ovulation rates are higher when combined with clomiphene. Patients with elevated pretreatment levels of testosterone show the best results in resumption of ovulation with significant reduction in testosterone. Those with raised fasting insulin responded less and those with normal testosterone showed no effect.

Thiazolidinediones include rosiglitazone and pioglitazone. They are less effective than metformin in decreasing insulin resistance and lead to weight gain and are category C drug in pregnancy [4]. They are synthetic agonists for peroxisome proliferator-activated receptor gamma (PPAR), which serves as a regulator gene for metabolism of carbohydrate, fats, and lipids [3].

Myoinositol positively modulates insulin sensitivity in nonobese PCOS patients without compensatory hyperinsulinemia, improving hormonal parameters. Thus, myoinositol improves reproductive axis functioning in PCOS patients. Menstrual cyclicity was restored in all ammenorrheic and oligomenorrheic patients.

Clomiphene citrate is a nonsteroidal triphenylethylene derivative [3]. It is a selective estrogen receptor modulator which normally acts as estrogen receptor antagonist, but when the level of estrogen in the body is very low, it acts as an agonist [4]. It is available as two racemic isomers En (62 %) and Zu (38 %). Clomiphene is excreted in stools and around 85 % is excreted in 6 days. En clomiphene is more potent and responsible for the action of clomiphene for ovulatory induction. Zu clomiphene is less potent and stays in circulation for a longer time. It accumulates over series of time and is probably responsible for adverse effect of clomiphene on endometrium and cervix [19].

The efficacy of clomiphene citrate in unexplained infertility is by inducing superovulation of more than a single ovum. But studies have found out that only clomiphene citrate with timed intercourse is no better than no intervention as there is no improvement in only clomiphene citrate group. IUI along with clomiphene citrate is more useful in patients with unexplained infertility as it leads to increase in pregnancy rate [22]. At least three cycles of clomiphene citrate should be offered.

The dosing of clomiphene citrate should be based upon BMI, age, AMH, antral follicle count, response to previous stimulation, and day 2 FSH [8]. The dose of the tablet is 50 mg per day, but in the case of lean PCOS, the dose is as less as 25 mg/day. The maximum response is obtained with 150 mg/day. The maximum dose that can be safely used is 250 mg/day, but that is rarely required. Higher dose may be useful in patients with higher BMI. In obese, anovulatory women with at least 2 years of infertility, success rates generally are lower, with 16 % achieving live birth in women with BMI >35 kg/m² compared with 28 % for women with BMI 14 < 30 kg/m².

If clomiphene citrate is used for ovulation induction, then it must be given for a maximum of 3–6 cycles. The likelihood of pregnancy is very low after this period. The cumulative pregnancy rate after six cycle of CC is 50–60 %[9]. If no pregnancy occurs after six cycles, then the second line of therapy with gonadotrophins or laparoscopic ovarian drilling should be offered.