A Cochrane review included 2 studies with a total of 305 subjects. Anovulatory women being treated with clomiphene citrate were randomised to receive urinary hCG as an ovulatory trigger or no treatment. Urinary hCG did not result in increases in the primary outcome of live birth rate over no treatment (OR 0.98, 95% CI 0.52 to 1.83). hCG did not increase ovulation rate ( OR 0.95, 95% CI 0.49 to 1.83), clinical pregnancy rate (OR 1.02, 95% CI 0.56 to 1.88), multiple pregnancy rate (OR 0.47, 95% CI 0.05 to 4.59), miscarriage rate( OR 1.18, 95% CI 0.18 to 7.66) and preterm delivery (OR 0.12,95% CI 0.00 to 6.29) compared to no treatment. Trials evaluating other ovulation triggers were not identified.
Comment: The quality of evidence is downgraded by study quality (lack of blinding) and by imprecise results (few patients and wide confidence intervals).