Objective: To determine if uterine and ovarian measurements can significantly distinguish between precocious puberty (PP) and premature thelarche (PT) and whether ultrasound has any advantage over the gonadotropin-releasing hormone (GnRH) stimulation test.
Methods: One hundred and three girls referred consecutively for evaluation of breast budding before age 8 years underwent physical examination, GnRH stimulation test, bone age assessment, and transabdominal pelvic ultrasound. The diagnosis of PP or PT was based on clinical judgment. The clinical, laboratory, and ultrasound data of the PP and PT groups were compared.
Results: Eighty-one girls were diagnosed with PP and 22 with PT. Significant differences in most of the uterine and ovarian measurements were found between the groups. On logistic regression analysis, bone age standard deviation score, uterine transverse diameter, and uterine volume were the most significant variables predicting PP. Comparison of 30 girls with PP and 21 with PT in whom peak luteinizing hormone was <5 mIU/ml on the GnRH stimulation test, using analysis of variance, yielded significant differences in uterine width (P<0.001), fundus diameter (P <0.04), uterine volume (P= 0.006), and ovarian circumference (P <0.02).
Conclusions: Increased uterine and ovarian measurements may be an early and sensitive sign of PP. Pelvic ultrasound, a noninvasive, inexpensive, and reliable tool, may give the clinician a complementary indication to the GnRH test in distinguishing isolated PT from early-stage PP in girls with early breast budding.