Human Chorionic Gonadotropin If a dominant follicle develops, but there is no spontaneous LH surge, human chorionic gonadotropin (hCG) can be used to induce final follicular maturation, with ovulation occurring approximately 40 hours following administration (136,156). Although administration of hCG at midcycle does not appear to improve conception chances in most infertility patients using clomiphene citrate, it may be useful for patients with known ovulatory dysfunction (157–159). The medication may be derived from urine (5,000 to 10,000 IU intramuscularly) or manufactured with recombinant technology (250 μg subcutaneously, equivalent to 5,000 to 6,000 IU urinary) (156).
Timing of Intrauterine Insemination When IUI is added to the therapeutic protocol, insemination typically is performed 24 hours following the LH surge (157). However, given data that ovulation can occur much later than this, it is not surprising that no differences in pregnancy rates were found when IUI was performed between 24 and 60 hours following the LH surge (160). Although timing of IUI is typically performed 36 hours following hCG administration to coincide with follicle rupture when hCG is added to trigger ovulation, no significant differences in pregnancy or live birth rates are seen whether IUI is performed at 24 or 36 hours following the hCG trigger (161).
Insulin Sensitizers Insulin resistance is thought to play a central role in the pathogenesis of PCOS (Table 32.7). Metformin is an oral biguanide that is approved for the treatment of non– insulin-dependent diabetes and has been used in PCOS to increase the frequency of spontaneous ovulation. Metformin acts by several mechanisms, including inhibition of gluconeogenesis in the liver and increasing the uptake of glucose in the periphery (162). Although the literature is conﬂicting, larger studies have suggested that the live birth rate with metformin alone (7.2%) is lower than that achieved with clomiphene, and the combination does not confer additional benefit over clomiphene alone (142,163). Obese patients are less likely to respond to metformin (164). It remains unclear whether metformin decreases miscarriage rates in PCOS,
Table 32.7 Clinical Findings that Suggest Insulin Resistance and Hyperinsulinemia
Physical findings associated with insulin resistance
Waist-to-hip ratio >0.85
From Barbieri RL. Induction of ovulation in infertile women with hyperandrogenism and insulin resistance. Am J Obstet Gynecol 2000;183:1412–1418, with permission.