RESUMO
OBJECTIVE: To evaluate the effect of 6-sulphatoxymelatonin on the sleep quality of girls with precocious puberty. STUDY DESIGN: Ninety-nine girls were divided into three groups: GI, precocious puberty; GII, normal prepubescent; GIII, normal puberty. Questionnaires containing demographic and clinical data were applied. Blood was collected for hormonal evaluation for 6-sulphatoxymelatonin. The modified Rush Sleep Diary was used. RESULTS: The levels of 6-sulphatoxymelatonin were highest in the group without pubertal development (75.23 ± 10.84 ng/ml), second highest in the group with normal puberty (45.66 ± 3.87 ng/ml, p < 0.001) and lowest in the group with true precocious puberty (37.04 ± 5.47 ng/ml). The amount of day sleep was greater in the group without pubertal development compared to other groups. CONCLUSION: Despite the sleep data, melatonin may be involved in the precocious puberty process.