Adolescent girls with a history of precocious pubarche (PP) are known to be at increased risk for ovarian hyperandrogenism, an endocrinopathy related to reduced fetal growth, but the characteristics of their ovulatory function have not been fully documented. We assessed ovulatory function by weekly urinary LH and salivary progesterone measurements over 3 consecutive months in 85 adolescent girls with known weight and gestational age at birth: 49 girls had no history of PP (age, 14.7+/-1.7 yr), and 36 had a history of PP (age, 14.4+/-2.0 yr); 55 girls were in the early postmenarcheal phase (0-3 yr after menarche), and 30 were in the late postmenarcheal phase (> 3 yr after menarche). In girls with PP, the 17-hydroxyprogesterone (17-OHP) response to ACTH was determined at prepubertal diagnosis of PP, and serum androgen and gonadotropin concentrations were measured in adolescence together with insulin responses to an oral glucose load. Early postmenarche, the fraction of girls with ovulations was similar in the non-PP and PP subgroups (61% vs. 62%), as was the fraction of ovulatory cycles (25% vs. 22%). Late postmenarche, however, the fractions of ovulating girls and ovulatory cycles were strikingly higher (P < or = 0.001) in the non-PP than in the PP subgroup (91% vs. 20% and 47% vs. 12%). Within the PP subgroup, anovulatory girls were found to have a lower weight SD score at birth (mean+/-SEM) than ovulatory girls (-1.22+/-0.3 vs. -0.36+/-0.3; P = 0.03), a higher 17-OHP response to ACTH before puberty (333.1+/-31 vs. 203.8+/-26 ng/dL; P < 0.002), and, in adolescence, lower serum sex hormone-binding globulin levels and higher circulating LH, free androgen indexes, and insulin responses. In conclusion, these findings indicate that girls with PP are at increased risk for anovulation from late (not early) adolescence onward, particularly those girls with a low weight at birth and/or a high 17-OHP response to ACTH at prepubertal diagnosis of PP.