| ObjectiveThis research was aimed to identify the confounding factors of thyroid stimulating hormone(TSH)levels of neonatal heel-prick blood,which were important for monitoring the iodine status of population,especially for pregnant women and diagnosing the congenital hypothyroidism.MethodsThe data were provided by the program of a cross sectional study in Tianjin,China.A total of 988 pregnant women and their newborns were included in the study from April 2015 to May 2017.Maternal demographic information was recorded by questionnaire,including age,height,parity,etc.Height and weight were measured using standardized procedures.Body mass index(BMI,kg/cm~2)was calculated as weight(in kg)/height~2(in cm).The fasting blood and urinary samples were collected from all pregnant women at administration.After parturition,the information of duration of pregnancy,mode of delivery,neonatal sex,neonatal TSH,neonatal birth weight and neonatal birth height were recorded.We collect the heel-prick blood spot samples of newborns at 48-72 hours after birth.Results1.The iodine status:The maternal UIC’s median level was 156μg/L(IQR:106-219μg/L)and the rate of neonatal TSH>5mIU/L was 13.2%(130/988).2.Single factor analysis of neonatal heel-prick blood TSH level:(1)The neonatal TSH was significantly positive correlation with maternal age,BMI,parity,duration of pregnancy,season of parturition,neonatal birth height and weight(P<0.05).Conversely,there was no correlation between neonatal TSH and maternal UIC(r=0.02,P=0.725).(2)The neonatal TSH levels were significantly different categorized by○1 maternal age,the median level of neonatal TSH was higher when maternal age>30 years old(M(IQR):2.89 mIU/L(1.75-4.28 mIU/L),P<0.001);○2duration of pregnancy,the baby was born at term to a mother had a higher TSH level than those at preterm(M(IQR):2.57mIU/L(1.54-3.96 mIU/L)vs 1.59 mIU/L(1.05-2.94 mIU/L),P=0.009);○3 season of parturition,the median level of neonatal TSH was higher when the baby was born at winter(M(IQR):3.16 mIU/L(2.09-4.43mIU/L),P=0.001);○4 maternal TSH,the median level of neonatal TSH was higher when maternal TSH>2.23mIU/L than maternal TSH≤2.23mIU/L(M(IQR):2.66mIU/L(1.66-4.54mIU/L)vs 2.50 mIU/L(1.45-3.77 mIU/L),P=0.031).Conversely,no differences were found in the neonatal TSH according to maternal UIC(P=0.690).(3)The prevalence rate of neonatal TSH>5mIU/L was higher among mothers with BMI≥24 kg/cm~2 than those with BMI<18.5 kg/cm~2 and18.5-23.9 kg/cm~2((80/494)16.2%vs(2/17)11.8%and(48/477)10.1%,P=0.018).In addition,the prevalence rate of neonatal>5mIU/L was higher when their mothers’maternal TSH>2.23mIU/L than maternal TSH≤2.23mIU/L(80/722(11.1%)vs45/242(18.6%),P=0.453).Conversely,no differences were found in the prevalence rate of neonatal TSH>5mIU/L according to maternal UIC(P=0.453).3.Multivariate analysis of neonatal heel-prick blood TSH level:Although the binary logistic regression had adjusted the influence of maternal pregnant trimesters,maternal BMI≥24kg/cm~2 and maternal TSH>2.23mIU/L were independently significantly associated with having an infant’s TSH>5mIU/L(P=0.028 and 0.004,respectively).Mother with BMI≥24kg/cm~2 had the higher risk of having an infant’s TSH>5mIU/L compared with the infants,whose mother’s BMI between 18.5-23.9kg/cm~2.An increased risk of having a baby with TSH>5mIU/L was again observed in mother with TSH>2.23mIU/L(OR(CI):2.028(1.312-3.134),P=0.001).Conclusion1.The pregnant women maybe at iodine deficiency status,especially for the third trimester.2.In this study,maternal BMI and TSH during pregnant may influence the neonatal heel-prick blood TSH levels in early neonatal period. |
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