In 55 % of cycles treated with 15 mg/day and in 78 % of cycles treated with 30 mg/day ( p < 0.001 ) we observed dysfunctional ovulation defined as follicular rupture not preceded 24-48 h earlier by an LH peak or preceded by a blunted LH peak ( < 21 IU/l ) or not followed by an elevated serum P level > 12 nmol/l .