Many clinical hypothyroidism in pregnancy Mommy despite taking levothyroxine (L-T4) has maintained normal thyroid function, but postpartum b
Many clinical hypothyroidism in pregnancy Mommy despite taking levothyroxine (L-T4) has maintained normal thyroid function, but postpartum baby still very worried about whether there will be hypothyroidism, often asked the relevant problems in our clinic or network consulting, the "Chinese Medical Association endocrine society" and "Chinese Medical Association Wai production of" medical branch recently prepared "pregnancy and postpartum thyroid disease diagnosis and treatment guidelines (provisional Edition)" in the relevant content from the following, we hope to help.
Etiology and screening of neonatal hypothyroidism
Congenital hypothyroidism (CH, referred to as congenital hypothyroidism) the prevalence rate is about 1/3000-40000. The etiology of CH including thyroid hypoplasia (75%), disturbance of thyroid hormone synthesis (10%), central hypothyroidism (5%), neonatal transient hypothyroidism (10%). Since 1981 domestic screening of neonatal congenital hypothyroidism, the current national screening coverage has exceeded 60%, the incidence rate was 1/2050.
Screening indicators commonly used internationally is heel blood TSH (dried blood spot specimens). Full-term newborn blood collection time is 48 hours after delivery -4 days. If the specimen is taken 1 to 48 hours after birth, it may be affected by the pulsatile secretion of TSH after birth. Produce positive results. Chinese Ministry of health neonatal disease screening technical specifications (2010 Edition), the term newborn born within 72-7 days to take specimens. Premature infants can be delayed until 7 days after birth to take specimens. The positive cut-off point of TSH concentration value of laboratory and kit according to the set of general > 10 ~ 20mIU/L for screening.
Two, the diagnosis of neonatal congenital hypothyroidism
If the heel blood TSH positive screening, need to immediately recall with serum thyroid function test (venous blood specimens). Primary hypothyroidism, primary subclinical hypothyroidism, TBG deficiency and central hypothyroidism serological diagnosis standard reference table, according to this standard was born 2 weeks in the reference value set. Clinicians should take into account the normal range of ages and the effects of different laboratory tests and methods.
TSH> 9mIU / L; FT4< 0.6ng / dL
TSH> 9mlU / L; FT4 normal (0.9-2.3ng / dL)
TSH< 9mlU / L; FT4 normal (0.9-2.3ng / dL)
TT4 reduction (< 5ng / dL); T3RUR> 45%
TSH< 9mIU / L or normal; FT4 reduction (< 0.6ng/dL);
TT4 reduction (< 5ng / dL);
CH cases have been confirmed in 90% CH patients with TSH> 90mIU/L; at least > 30mIU/L; 70%CH; 6.5ug/dL (84nmol/L); FT4< 10pmol/L; TT4<.
CH diagnosed need further examination of etiology, such as primary hypothyroidism thyroid ultrasound, thyroid need to do 99m Tc (or 131 iodine scan, I do not recommend iodine -131 scan) and serum Tg and thyroid stimulating blocking antibody (TSBAb) determination; central hypothyroidism need to do TSH beta gene analysis and TRH gene analysis and other pituitary hormone determination, optic nerve and the hypothalamic pituitary MRI examination.
Recommendation 1: neonatal congenital hypothyroidism screening should be born in 48 hours after -75 days, if in 2 days after birth to 4 days for the best. Heel straight TSH (DBS specimen) cut-off is 10-20mIU / L. (recommended level A)
Recommendation 2: screening positive should immediately review serum TSH, TT4. The diagnostic criteria are determined by the laboratory reference values of the laboratory. Recently, Lafranchi proposed TSH> in serum of JCEM, 9mlU / L, FT4< 0.6ng / dL as the diagnostic criteria of CH. Need to combine the results of CH etiological examination. (recommended level A)
Three, the treatment of neonatal congenital hypothyroidism
Congenital hypothyroidism is confirmed as soon as possible to use levothyroxine (L-T4) treatment in 1 to 2 weeks. The serum T4 levels returned to normal, 2 to 4 weeks of restoring to normal levels of serum TSH. The CH report began to age and treatment of children with mental retardation were significantly correlated, born within 2 months of starting treatment of IQ and normal children have no significant difference; the beginning of the 3 month treatment IQ of 89; 3 to 6 months to start treatment 71 IQ; 6 months after the beginning of treatment an IQ of 54.
The goal of CH treatment is the serum FT4 in the upper range of reference value of 50%; the serum TT4:1 ~ 2 10-16 g / dL, > the upper range at the age of 2 and the reference value of 50%; serum TSH:< 5 mIU / L, 0.5 ~ 2.0mlU / L range is the best.
The initial dose of levothyroxine (L-T4) was 10 to 15ug / kg / D, once daily. The various causes of L-T4 recommended dose: thyroid agenesis 15ug / kg / D, 12ug / kg / D ectopic thyroid, thyroid hormone disorders in 10ug / kg / d.