| Background: The incidence of sexual dysplasia has increased gradually in recent years,which cause the attention of all the sectors of society,especially for pediatric endocrinologist.The minipuberty is a normal period from intrauterine to extrauterine life,when newborns and young infants experience the transient surge of gonadotropin and sex steroids,perhaps related to the sudden withdrawal of maternal and placental hormones.The importance of minipuberty for sexual dysplasia and its related diseases is gradually be elevated.However,there is no consensus on the endpoint or age definition on it.One of the important reasons maybe that there is not enough evidence-based basis.Due to the pulsatile secretion of Gn and sex hormones,a single blood sample can not objectively reflect the actual level.While the urine determination can reflect the average level of Gn and sex hormones,and urine collcetion is non-invasive and convenient.In recent years,more and more researchs on urine Gn and sex hormones in children have been reported.However,there are few research on the characteristics of urine Gn and sex hormones in minipuberty,especially for the significance of the age definition in minipuberty.Objective: To measure urine Gn and sex hormones of children aged 0~6 years old and explore their significance for the age definition of minipuberty.Methods: Healthy children aged 0~6 yr from Mashan and Hudai Town communities in Binhu District,Wuxi,Jiangsu and normal newborns aged 0-7 days from our hospital were included in this study.Morning urine were collected.Then we measured follicle stimulating hormone(FSH),luteinizing hormone(LH),estradiol(E2)and estriol(E3)in morning urine.Testosterone(T)for only boys and progesterone(Pro)for only girls were also determinated.All the results were corrected with creatinine(Cr)and showed as median(25th-75 th percentiles).Follow up Gn and sex hormone levels in children with originally sex hormone abnormalities and secondary sexual characteristics.Results:(1)A total of 3344 children(1813 boys and 1531 girls)were involved.They were divided into 13 groups by age.There were 88,117,124,121,124,104,139,140,121,347,762,731 and 426 cases in 0~7 day,1~3 months,3 months~,6 months~,8 months~,1yr~,1.5 yr~,2 yr~,2.5 yr~,3 yr~,4 yr~,5 yr~ and 6~7 yr group,respectively.Follow-up: 11 children aged 3~6 yr with originally abnormal sex hormones included 6 girls and 5 boys;10 children aged 3~6 yr with secondary sexual characteristics included 6 girls and 4 boys.The detection rate of girls with sexual precocity was 4.29%.(2)The detectable rates of LH,FSH,E3,E2 and T in boys were 11.4%,88.3%,97.08%,99.89% and 96.19%.The detectable rates of LH,FSH,E3,E2 and Pro in girls were 17.83%,89.94%,97.32%,99.80% and 98.89%.(3)Boys: FSH showed a gradual upward trend.FSH/Cr gradually rose to the peak at 1~3 months after 7 days,then slowed down after 6~8 months.E3,E2 and T decreased rapidly after 7 days.E3 and T slowed down in 3~6 months.E2 gradually slowed down after 1~3 months.E3/Cr,E2/Cr and T/Cr decreased rapidly after 7 days,then slowed down in 6~8 months.(4)Girls: FSH gradually increased with age from 7 days to 2~2.5 yr,and gradually decreased after 2.5 yr.FSH/Cr showed an upward trend with age after 7 days,and the peak value was at around 3~6 months,and then it showed a downward trend until 1.5~2 yr.E3,E2 and Pro decreased rapidly after 7 days.E3 and Pro slowed down in 3~6 months.E2 gradually slowed down after 1~3 months.E3/Cr,E2/Cr and Pro/Cr decreased rapidly after 7 days.E3/Cr and Pro/Cr slowed down in 3~6 months.E2/Cr gradually slowed down after 1~3 months.(5)Follow-up: girls with abnormal sex hormones had an abnormality Gn and sex hormones in the follow-up and one of them with sexuality occurred before 8yr.Most girls with sexuality had normal hormones levels and sexual signs disappeared in the follow-up,but two of them had develop into slow-moving precocious puberty.Conclusion:(1)There are different trends of urine Gn and sex hormones in boys and girls during minipuberty.FSH of boys shows a gradual upward trend.E3,E2 and T decrease rapidly after 7 days.E3 and T slow down before 6 months.E2 gradually slow down around 3 months.FSH of girls under 6 yr increases with age from 7 days to 2.5 yr,and gradually decreases after 2.5 yr.E3 and Pro slow down before 6 months.E2 gradually slows down around 3 months.(2)By comprehensive analysis of urinary Gn and urinary sex hormone trends,the age definition of minipuberty in both boys and girls may be before 6 months of age,the post minipuberty can be from about 6 months to 6 yr at least.(3)Combined urine sex hormones and Gn detection may have certain clinical value for judging the functional status of hypothalamic-pituitary-gonadal axis in children under 6 yr,including minipuberty and related diseases. |
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