Validation of an Accurate and Noninvasive Tool to Exclude Female Precocious Puberty: Pelvic Ultrasound With Uterine Artery Pulsatility Index

OBJECTIVE. The purpose of this study is to validate the accuracy of pelvic ultrasound (US) with the evaluation of uterine artery pulsatility index (PI) to exclude female precocious puberty. MATERIALS AND METHODS. Tanner breast development score, luteinizing hormone (LH) peak after gonadotropin-releasing hormone (GnRH) stimulation, and uterine and ovarian volumes and diameters were assessed with pelvic US in 495 girls at a single institution. The study population was divided as follows: prepubertal (n = 207), pubertal with physiologic activation of the hypothalamic-pituitary-ovarian axis (n = 176), and central precocious puberty (CPP; n = 112). PI was measured with spectral Doppler US at the ascending branches of the right uterine artery (50-Hz filter; time gain compensation, 73; pulse repetition frequency, 6.6). ROC analyses and t tests were performed. RESULTS. The mean (± SD) PI values in the prepubertal, pubertal, and CPP groups were 6.3 ± 1.4, 3.4 ± 1.1, and 4.1 ± 1.5, respectively (p < 0.001). The best PI cutoff value to distinguish pubertal from prepubertal girls was 4.6 (sensitivity, 83%; specificity, 94%; positive predictive value, 95%; negative predictive value, 80%; accuracy, 87%). ROC AUC values for LH peak (cutoff value, 5 mU/mL) and for spectral Doppler US PI plus longitudinal uterine diameter (i.e., the combination of a PI of 4.6 with a longitudinal uterine diameter of 35 mm) were 0.9272 and 0.9439, respectively (p = 0.7925). The negative predictive values for LH peak and for PI plus longitudinal uterine diameter were 89% and 88%, respectively. CONCLUSION. A PI greater than 4.6 at spectral Doppler US combined with a longitudinal uterine diameter less than 35 mm allows noninvasive exclusion of female precocious puberty with comparable accuracy and lower costs compared to examination of LH peak after GnRH stimulation. Therefore, PI plus longitudinal uterine diameter might be used as a noninvasive first-line test to exclude precocious puberty and thereby avoid further investigations.