# Congenital hypothyroidism - Category: chronic - Review status: reviewed (every claim checked against a document named on this page) - Sources: Congenital Hypothyroidism - StatPearls (NCBI Bookshelf NBK558913) - https://www.ncbi.nlm.nih.gov/books/NBK558913/ · Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism-full.txt) · Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism-clinical.txt) - Verified date: 2026-08 ## Verified against - Congenital Hypothyroidism - StatPearls (NCBI Bookshelf NBK558913) - https://www.ncbi.nlm.nih.gov/books/NBK558913/ - Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism-full.txt) - Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism-clinical.txt) ## Treatment metadata - Screen, confirm, and start treatment inside the first two weeks - Levothyroxine — oral.solid ## Complete treatment card ```text CONGENITAL HYPOTHYROIDISM Sources: Congenital Hypothyroidism - StatPearls (NCBI Bookshelf NBK558913) - https://www.ncbi.nlm.nih.gov/books/NBK558913/ · Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism-full.txt) · Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism-clinical.txt) Review status: REVIEWED against 3 sources listed above (2026-08) IS IT THIS? - reference only, to read alongside your own examination SYMPTOMS - what the patient reports (3) - Most newborns show few or no signs at birth because some maternal thyroid hormone still crosses the placenta - Early features in severe cases, appearing within the first weeks, include lethargy, low muscle tone, wide fontanelles, feeding trouble, prolonged jaundice, a hoarse cry, constipation, and low body temperature [constipation · hypothermia · jaundice · lethargy] - Noisy breathing, a stuffy nose, and intermittent blue lips around the mouth can occur from swelling of the airway tissue [blocked nose · cyanosis] SIGNS - what you find (2) - Later features around six weeks include coarse facial features, a flat nasal bridge, puffy eyelids, an enlarged tongue, coarse hair, and thick, dry, cold, mottled skin [dysmorphic features · eyelid swelling] - Absence of the lower femoral growth plate on a knee X-ray at diagnosis marks severe disease and predicts poorer later intelligence and motor scores TESTS (9) - Newborn screening uses a heel-prick blood spot; TSH is the most specific test for the primary form, while T4 is more sensitive since it also catches rarer central disease - Screening should ideally happen between 2 and 4 days of life, or before hospital discharge if that isn't possible - Preterm, low-birth-weight, or NICU infants need a second screen since TSH rise can be delayed, seen in about half of preterm babies - A repeat TSH of 10 mU/L or higher is counted as a positive screening result - A low free T4 together with a high TSH confirms primary hypothyroidism - Normal T4 with high TSH defines subclinical disease; treatment starts if TSH exceeds 20 mIU/L, or if it stays at 10 mIU/L or above after four weeks when only mildly elevated - Thyroid ultrasound shows the gland's size and structure but may miss a thyroid that sits under the tongue - A radionuclide thyroid scan can locate a misplaced gland or show absent or underdeveloped tissue, and shows no uptake with blocking antibodies or an iodine-trapping defect - A low or absent serum thyroglobulin level suggests the thyroid gland never formed IF NOT THIS - what else fits (2) - A blood sample taken in the first 24 hours can show a falsely high TSH from the normal post- birth TSH surge, requiring a repeat test - Premature infants can show a low free T4 with a normal TSH from an immature hormone axis, a pattern hard to distinguish from a central cause or non-thyroid illness Source Congenital hypothyroidism - disease-level clinical article (congenital-hypothyroidism- full.txt) Status traced to the source above 1. SCREEN, CONFIRM, AND START TREATMENT INSIDE THE FIRST TWO WEEKS[1st line] Adult Source Congenital Hypothyroidism - StatPearls (NCBI Bookshelf NBK558913) - https://www.ncbi.nlm.nih.gov/books/NBK558913/ Why The whole value of this diagnosis is in its timing. The baby usually looks normal, the screening test finds it, and the intellectual outcome depends on treatment starting before the second week of life. So the primary-care job is to make sure the heel-prick was done, chase the result, and get the confirmatory thyroid function test and the first dose arranged without waiting for a clinic slot. Caution THE BABY LOOKS WELL - a newborn with congenital hypothyroidism frequently has no symptoms at all, and it is the newborn screen (NBS) that finds them. There is no examination finding to wait for. A normal-looking newborn does not exclude it and never has. TIME THE HEEL-PRICK - the screen is best taken somewhere between 2 and 4 days of life; failing that, take it before the baby leaves hospital. A sample taken too early misleads: where a baby went home early and the screen was taken inside the first 24 hours, the TSH may read high simply because it surges after delivery in response to the cold. That is a false positive, and it means screening a second time. TREAT BEFORE TWO WEEKS - screening programmes, and starting L-T4 before 2 weeks of life, are what prevent intellectual damage and give the best neurodevelopmental result. Start early enough and at a large enough dose - before the 2nd week - and global intelligence comes out where it should. This is the whole reason the pathway is urgent. THE DECISION RESTS ON THE BLOOD TEST, NOT ON A SCAN - imaging is not advised routinely, because what it shows changes nothing about the treatment. What decides whether therapy starts is the abnormal thyroid function test, and nothing else. Do not let a waiting list for an ultrasound or an uptake scan delay the first dose. A PREMATURE BABY'S RESULT IS HARDER TO READ - a preterm infant may have the hypothyroxinaemia of prematurity: a low free T4 with a normal TSH, from a hypothalamic- pituitary-thyroid axis that has not matured. Most such babies have normal thyroid function by 6 to 10 weeks. Repeat rather than treat or dismiss on one abnormal preterm sample. EXAMINE FOR THE THINGS THAT TRAVEL WITH IT - other congenital malformations turn up more often in these children: cardiac ones above all, septal defects among them, along with renal abnormalities, and a raised risk of neurodevelopmental disorder. Examine the baby thoroughly, and include a hearing screen. IODINE CUTS BOTH WAYS - too much iodine can cause it, and so can too little, in a baby born where goitre is endemic or iodine is scarce. Ask what was applied to the mother's skin or the cord, and what the family's salt is. TELL THE PARENTS WHY THE FOLLOW-UP MATTERS - the parents need to understand what congenital hypothyroidism is, and why treating it early and at the right dose is what keeps the child's development on course. A family who stop the syrup when the baby "seems fine" is the commonest way this goes wrong. 2. LEVOTHYROXINE [1st line] Adult Peds 10-15 mcg/kg/day (MICROGRAMS PER KILOGRAM PER DAY, NOT MILLIGRAMS. A typical term newborn takes 37.5 to 50 micrograms once daily, which is most of a 50-microgram tablet, and a ten-fold slip here is a thyrotoxic baby. Start only on a confirmed abnormal thyroid function test, and hand the monitoring to paediatric endocrinology - the dose is adjusted on repeat tests, not on how the baby looks. The article gives no adult dose for this indication and none is printed. 10 to 15 mcg/kg/day is the NEWBORN starting figure; the requirement per kilogram falls steadily through childhood, so it must never be carried up to an older child. A child already on treatment takes the dose their endocrinologist titrated, never a figure from this table.) 3kg -> 30-45 mcg/day 4kg -> 40-60 mcg/day 5kg -> 50-75 mcg/day This mg/kg figure applies up to 5 kg only - above that, dose on specialist advice Source Congenital Hypothyroidism - StatPearls (NCBI Bookshelf NBK558913) - https://www.ncbi.nlm.nih.gov/books/NBK558913/ Why Indication: levothyroxine must be started the moment congenital hypothyroidism is diagnosed, and L-T4 on its own is the treatment of choice. Amount: the article asks for a higher opening dose, 10 to 15 micrograms/kg/day - 50 micrograms a day in a full-term infant with severe disease - and presses that particularly where the pretreatment T4 was very low. Caution HOW TO GIVE IT TO A NEWBORN - crush the L-T4 tablet, mix it into a little water or breast milk, 1 to 2 ml of it, and give it by small spoon or syringe. Give it at the same hour every day, and at a different hour from calcium, iron or soya, all of which get in the way of its absorption. Soya formula and an iron drop given together are a common cause of an unexplained high TSH. THE HIGH START IS DELIBERATE, AND SO IS COMING DOWN FROM IT - starting high brings the serum T4 back to normal in 3 days and the TSH inside two weeks. Most term babies with severe disease need that high dose only briefly - 50 ug a day - and then come down to 37.5 ug a day once the TSH has normalised, so that they are not overtreated. OVERTREATMENT IS NOT HARMLESS - too much L-T4 has been reported to harm cognitive and behavioural outcomes. Watch the thyroid function tests closely after starting the drug and after every change of dose, so that they come to normal and stay there without tipping over into overtreatment. THE MONITORING SCHEDULE, BECAUSE IT IS THE TREATMENT - the first repeat thyroid function test (TFT), free T4 and TSH both, is taken 1 to 2 weeks after L-T4 is begun, and then every two weeks until the TSH is fully normal. After that, repeat it every 1 to 3 months until the child is 1 year old. And after any change: adjust the dose, or change the preparation, and a repeat TFT follows in 4-6 weeks. THE TARGET - aim for a total T4 sitting in the top half of the range that applies at the child's age, and a TSH anywhere inside that range. IT IS NOT ALWAYS FOR LIFE, BUT DO NOT STOP IT YOURSELF - the guidelines as they stand keep a child on L-T4 to 36 months of age at least. At that point a trial off it can be considered, to find out whether the hypothyroidism was permanent. Needing under 2.8 mcg/kg/day by the third treatment year predicts that it was transient. The trial is planned and re-tested at two weeks, not improvised. Egypt T4-THYRO 50 MCG 100 TABS. MUP 9.00 EGP (0.09/unit) T4-THYRO 100 MCG 100 TABS. MUP 11.00 EGP (0.11/unit) HYPOTHYRONOR 25 MCG 100 TABS. ACDIMA INTERN... 32.00 EGP (0.32/unit) EQUITHERA 50MCG 50 TABS. MARCYRL PHARM... 26.00 EGP (0.52/unit) EUTHYROX 25MCG 50 TAB. MERCK KGAA F.... 33.00 EGP (0.66/unit) EQUITHERA 100MCG 50 TABS. MARCYRL PHARM... 39.50 EGP (0.79/unit) EUTHYROX 75MCG 100TAB. MERCK KGAA F.... 137.00 EGP (1.37/unit) EUTHYROX 100MCG 100 TAB. MERCK KGAA F.... 158.00 EGP (1.58/unit) Prices are indicative (dataset snapshot 2026-06); verify with the pharmacy. ``` --- Dawaa Reference is a reference for prescribers, not a medical device, and does not replace clinical judgement. [Privacy policy](/privacy)