This article is more than 5 years old. Information may no longer be current.
GnRH stimulation test not predictive of precocious puberty in girls with premature thelarche
Click Here to Manage Email Alerts
The gonadotropin-releasing hormone stimulation test is not a reliable predictor of central precocious puberty in girls with premature breast development in the first 3 years of life, according to recent study findings.
In a retrospective, longitudinal study, researchers evaluated 450 girls who presented at the Outpatient Endocrine Clinic of Bambino Gesu Children’s Hospital in Rome with thelarche before age 3 years. All children were seen at the clinic between 2004 and 2011. An initial examination was conducted and included detailed medical history and physical examination. The researchers measured and recorded the girls' weight, height and length. Pubertal stage also was determined based on Tanner’s criteria for breast development.
Girls whose thelarche was apparent at birth or within the first 6 months of life were seen for follow-up every 3 months (n=353). Those seen for thelarche that manifested between age 6 and 12 months with one sign indicating true precocious puberty and all girls with thelarche originating after age 12 months underwent a complete workup (n=97). This diagnostic workup consisted of left hand and wrist X-rays for evaluating bone age, pelvic ultrasound scan, basal luteinizing hormone (LH) follicle-stimulating hormone (FSH) and 17-beta-estradiol measurements, and gonadotropin-releasing hormone (GnRH) stimulation test. Diagnosis of central precocious puberty in girls showing LH peak response to GnRH testing (>5 mU/mL) was made using tuber cinereum hamartoma at MRI or with normal MRI but pubertal progression during follow-up.
The researchers diagnosed idiopathic premature thelarche in 85 of the 97 girls who underwent the full workup. Central precocious puberty was diagnosed in nine girls, and peripheral precocious puberty in three girls. Six (7%) of the girls with idiopathic premature thelarche had longitudinal diameter of the uterus >34 mm, and six (66.6%) of the children with central precocious puberty had longitudinal uterine diameter of >34 mm.
One (1.17%) girl with idiopathic premature thelarche had basal LH >0.2 mU/mL, and eight (88.8%) girls with central precocious puberty had basal LH >0.2 mU/mL. LH peak was > 5 mU/mL in 31 (36.4%) of those with idiopathic premature thelarche and 9 (100%) of those with central precocious puberty. The ratio of LH peak to FSH peak was >1 in six (66.6%) girls with central precocious puberty.
The study researchers said none of the current tests alone is predictive of girls who will progress to precocious puberty, and elevated LH responses to GnRH are not related to progression toward puberty. The joint measurement of basal LH and longitudinal uterine diameter offers a viable screening option to identify patients who should receive GnRH testing.
“Clinical monitoring is, in any case, mandatory, and the parents of a girl with thelarche onset in the first three years of life should be informed in detail about the possible progression to a true precocious puberty,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.
Perspective
Back to Top
Alan D. Rogol, MD, PhD
This study shows that for an experienced clinician who follows a case like this longitudinally, there is often no need to do more than that. In instances where there are hints that something more significant is wrong, the clinician can do a workup, but again, that’s a small percentage, and even among those that undergo a workup, there is a terribly small percentage of people with the pathological processes known as central precocious puberty or peripheral precocious puberty. I think this research shows that clinicians can follow patients and look for obvious signs, such as breast development, ≥ Tanner Stage 3, pigmentation of the areola or marked acceleration of height velocity. Those are important because they indicate that there is plenty of estrogen, and plenty of growth hormone. Enlargement of the uterus is important, too, because that’s a biological signal; that’s not a number that could have been mixed up with someone else’s. Biology always trumps lab values; there is no one test that can reliably predict precocious puberty. Basal LH and uterine diameter may be the best combination, but it’s by no means 100%.
Collapse
Bizzarri C. J Clin Endocrinol Metab. 2013;doi:10.1210/jc.2013-3292.
Click Here to Manage Email Alerts