1 / 57

Thyroid disorders in pregnancy

Thyroid disorders in pregnancy. Dr.K.Saravanan. ECG & ECHO Club of Trichy. Control of thyroid function. Thyroid Disorders & Pregnancy. Specific to Pregnancy : Transient hyperthyroidism of HG Postpartum thyroiditis

griffith-torres
Download Presentation

Thyroid disorders in pregnancy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Thyroid disorders in pregnancy Dr.K.Saravanan ECG & ECHO Club of Trichy

  2. Control of thyroid function

  3. Thyroid Disorders & Pregnancy Specific to Pregnancy : Transient hyperthyroidism of HG Postpartum thyroiditis Neonatal & fetal hyperthyroidism Neonatal & fetal hypothyroidism Not specific to Pregnancy : Thyrotoxicosis , Hypothyroidism Thyroid nodules , Thyroid neoplasia

  4. Physiological adaptation in pregnancy

  5. Clinical presentation - 1 A 19 year old primi with H/o 54 days amenorrhea was referred by obstetrician with C/o palpitations, weight loss of 2-3 months duration (8 kg), Her haemoglobin was 9.8 g/dl, HR  120/mt with prominent eye sign.

  6. Q1 In a background of clinical suspicion of Graves disease, the preferred investigation of choice : • TSH, T3, T4 • TSH, FT4, FT3 • TSH, FT4 4. TSH, FT4, Anti-TPO antibodies

  7. Thyroid Function Tests in Pregnancy-hyperthyroidism TSH Low FT4 High Normal Hyper thyroidism FT3 Subclinical Hyperthyroidism Normal

  8. Q2 Her TSH was < 0.001 (n 0.3-4.5 mIU/L)and FT4- 8.9 (n 0.932-1.71 ng/dl). Her TPO antibodies were positive. Drug of choice is Propanolol + • Carbimazole • Methimazole • PTU

  9. TSH  lowFT4 ,FT3normalSubclinical hyperthyroidismobserve • TSH  low • FT4  high • Clinical  hyperemesis • Observe , fluid therapy • TSH  low • FT4  high • Clinical  thyrotoxicosis • Anti-TPO antibodies +ve • Treat with PTU

  10. Thyrotoxicosis & Pregnancy • Causes: • Graves’ disease • TMNG, toxic adenoma • Thyroiditis • Hydatiform mole • Gestational hCG-asscociated Thyrotoxicosis • Hyperemesis gravidarum   hCG • 60%  TSH, 50%  FT4 • Resolves by 20 wks gestation • Only Rx with ATD if persists > 20 wk

  11. Hyperthyroidism & Pregnancy Useful Physical Signs : • Inappropriately lowweight gain for gest. age Goiter • Lid lag • Muscle weakness • Heart rate >100 • Onycholysis

  12. Thyrotoxicosis & Pregnancy • Risks: • Maternal: stillbirth, preterm labor, preeclampsia, CHF, thyroid storm during labor • Fetal: SGA, possibly congenital malformation (if 1st trimester thyrotoxicosis), fetal tachycardia, hydrops fetalis, neonatal thyrotoxicosis

  13. Approach in Pregnant & Suppressed TSH TSH < 0.1 TSH 0.1 – 0.4 Recheck in 5 wks FT4, FT3, T4, T3 Thyroid Ab’s Examine Still suppressed Normalizes Hyperemesis Gravidarum • Very High TFT’s: • TSH undetectable • very high free/total T4/T3 • hyperthyroid symptoms • no hyperemesis • TSH-R ab + • orbitopathy • goitre, nodule/TMNG • pretibial myxedema Don’t treat with PTU Abnormal TFT’s past 20 wk Treat Hyperthyroidism (PTU)

  14. Thyrotoxicosis & Pregnancy: Rx • No RAI ever (destroy fetal thyroid) • PTU • Start 100 mg tid, titrate to lowest possible dose • Monitor dose by: FT4, TSH • TSH alone is less useful (lags, hCG suppression) • Aim for high-normal to slightly elevated hormone levels • FT4 0.85-1.9 ng/dl and TSH 0.5 – 2.5mIU/L • 3rd trimester: titrate PTU down & decrease prior to delivery if TFT’s permit • Consider fetal U/S wk 28-30 to R/O fetal goitre • If allergy/neutropenia on PTU: 2nd trimester thyroidectomy • Propranolol

  15. TO summarize…. • Arrive at the diagnosis. • Correlate clinically • Rule out hyperemesis • Treat with PTU and propranolol in hyperthyroidism • Watch for neutropenia and infections • Monitor FT4 to assess control

  16. Points to ponder……. • Target FT4 is 0.85-1.9 ng/dl • TSH alone not helpful in monitoring PTU dose. • PTU dose adjusted every 3-4 weeks. • Symptoms improve in 3-4 wk but full response only after 8 weeks. • Block and replace therapy avoided in pregnancy due to risk to fetus. • Fetal monitoring is important • Subclinical hyperthyroidism-no intervention .

  17. Q4 Known hypothyroidism on 150 mcg Eltroxin with H/o 3 months amenorrhea comes with TSH,T3,T4 results.TSH-2.5(n 0.3 – 4.5 mIU/L) T4 – 16.4 (n 5.13-14.06 ug/dl) T3 – 3.2(n 0.84-2.02 ng/dl). Clinical Presentation - 2 • Eltroxin should be stopped. • Eltroxin dose should be increased in pregnancy • Check FT4 alone • Check FT4 ,FT3

  18. Thyroid Function Tests in Pregnancy-hypothyroidism TSH High FT4 Normal Low Subclinical Hypothyroidism Primary Hypothyroidism

  19. Thyroid & Pregnancy: Hypothyroidism • 85% will need increase in LT4 dose during pregnancy due to increased TBG levels (ave dose increase 48%) • Risks: • increased spont abort, HTN/preeclampsia, abruption, anemia, postpartum hemorrhage, preterm labour, baby SGA • Fetal neuropsychological development (NEJM, 341(8):549-555, Aug 31, 2001): • Cognitive testing of children age 7-9 • Untreated hypothyroid mothers vs. normal mothers: • Average of 7 IQ points less in children • Increased risk of IQ < 85 (19% vs. 5%)

  20. Causes & Diagnosis of Hypothyroidism • Causes: • Hashimoto’s (chronic thyroiditis; most common in developed countries) & iodine deficiency -> both associated with goiter • Subacute thyroiditis -> not associated with goiter • Thyroidectomy, radioactive iodine treatment • Iodine deficiency (most common worldwide; rare in US)

  21. Symptoms • Fatigue • Constipation • Cold intolerance • Weight gain • Muscle cramps • CTS • Insomnia , lethargy

  22. Points to ponder ….. • Known hypothyroid, eltroxin is increased by 30-50% in first trimester. • First time diagnosed start eltroxin at 1-2 mcg/kg /day • Target TSH is 0.5 – 2.5mU/L • TSH checked initially at 4-6 weeks and later 8 weeks • Space eltroxin and vitamin tablets to avoid interaction. • Postpartum-dose is reduced • Recommended iodide salt avg 250 mcg/day

  23. Q5 Clinical Presentation - 3 27 year old female and 3 MA with clinical features suggestive of hypothyroidism has a TSH  6.8 and FT4  1.2 ng. This is • Overt Hypothyroidism • Subclinical Hypothyroidism • Subacute Thyroiditis • Overt Hyperthyroidism

  24. Q6 Recommended approach in this patient • Start eltroxin • Repeat TSH every 4 weeks until 16-20 weeks and atleast once between 26-32 weeks • Repeat TSH & FT4 every 4 weeks until 16-20 weeks and atleast once between 26-32 weeks • No Intervention at all.

  25. Pregnancy: screen for thyroid dysfn ? • Universal screening not currently recommended: • ACOG, AACE, Endo Society, ATA • Controversial! • Definitely screen: • Goitre, FHx thyroid dysfn., prior postpartum thyroiditis, T1DM • Ideally, check TSH preconception: • 2.5-5.0 mU/L: recheck TSH during 1st trimester • 0.4-2.5 mU/L: do not need to recheck during preg • If TSH not done preconception do at earliest prenatal visit: • 0.1-0.4 mU/L: hCG effect (9% preg), recheck in 5wk • < 0.1 mU/L: recheck immediately with FT4, FT3, T4, T3

  26. Takeaways…….. • Thyroid is second commonest endocrine disorder in pregnancy. • Untreated hypothyroidism-fetus more affected • Untreated hyperthyroidism-mother more affected • Subclinical hypothyroidism- treat • Subclinical hyperthyroidism-followup • Routine screening- not recommended

  27. Management….. • LT4  1-2 mcg/kg/day • Dose adjustments by 25-50 mcg

  28. Hyperthyroidism & Pregnancy • TPO antibodies are increased in (80–90%) ofpatients with Graves disease + Other autoimmune disorders • (TRAbs) are increased in >80% of patients with Graves disease

  29. TSH Low High FT4 & FT3 FT4 Low Low High High Central Hypothyroid 1° Thyrotoxicosis 1° Hypothyroid If equivocal 2° thyrotoxicosis RAIU TRH Stim. • Endo consult • FT3, rT3 • MRI, α-SU MRI, etc.

  30. EFFECTS OF PREGNANCY ON THYROID PHYSIOLOGY

  31. Thyroid function in mother and foetus

  32. No TSH & FTI at end of 1st trimester as expected from hCG effect Requirement to increase LT4 dose occurred between weeks 4 -20 Despite exponential rise in estradiol throughout pregnancy (note y-axis units) TBG levels plateau at 20 wks

  33. 6. Women with type I diabetes. • 7. Women with other autoimmune disorders. • 8. Women with infertility who should have screening with TSH as part of their infertility work-up. • 9. Women with previous therapeutic head or neck irradiation. • 10. Women with a history of miscarriage or preterm delivery.

  34. Why treat hypothyroidism in preg? To prevent: • Premature birth • LBW • Abruption,PPH • Impaired neuropsychological development in child

  35. Physiologic thyroid adaptations in pregnancy • TBG • FT4, FT3 • hCG • TSH • Plasma iodide

  36. Thyrotoxicosis & Pregnancy • Diagnosis difficult: • hCG effect: • Suppressed TSH (9%) +/-  FT4 (14%) until 12 wks • Enhanced if hyperemesis gravidarum: 50-60% with abnormal TSH & FT4, duration to 20 wks • FT4 assays reading falsely low • T4 elevated due to TBG (1.5x normal) • NO RADIOIODINE • Measure: • TSH, FT4, FT3, T4, T3, thyroid antibodies? • Examine: goitre? orbitopathy? pretibial myxedema?

  37. Hyperthyroidism & Pregnancy Complications • First-trimester spontaneous abortions. • High rates ofstill births and neonatal deaths. • low birth weight infants : ↑ 2-3 folds. • Premature delivery. • Fetal or neonatal hyperthyroidism. • Intrauterine growth retardation .

  38. Case Presentation - 2 • A 19 year old primi with H/o 54 days amenorrhea was referred by obstetrician for C/o palpitations, weight loss of 2-3 months duration (8 kg), Her hemaglobin was 9.8 g/dl, HR  120/mt with prominent eye sign.

  39. Q1 In a background of clinical suspicion of Graves disease, the preferred investigation of choice : • TSH, T3, T4 • TSH, FT4, FT3 • TSH, FT4 • TSH, Anti-TPO antibodies

  40. Q2 Her TSH was < 0.001 and FT4 8.9. Her TPO antibodies were positive. Drug of choice: • Carbimazole • Methimazole • Betablockers • PTU

  41. Q3 Known hypothyroidism on 150 kg LT4 lost following and came 2 years later with H/o 3 months amenorrhea. She had stopped LT4 since conception and has checked TSH now which was 2.8 • Restart LT4 in preconception dose • Wait for 4 weeks and recheck TSH • Restart LT4 in low dose • Wait till delivery and then restart LT4

  42. The Fetal Thyroid • Begins concentrating iodine at 10-12 weeks • Controlled by pituitary TSH by approximately 20 weeks

  43. 10-12 wks of gestation: Fetal thyroid concentrates iodine, synthesize T3 and T4. The fetal pituitary differentiates. Prior to 12 weeks the mother is the sole source of thyroid hormone to the fetus. Fetal thyroid function is at low basal level till 18-20 wks At birth TSH 70uU/ml. Day 2max. TSH 12uU/ml

  44. Treatment indicated if FT4>2.0ng/dl • PTU 50-100mg q12 hours in pt. with minimal symptoms (doses>200 mg of PTU can result in fetal goiter & Hypothyroidism • Pt with large goiters & long disease duration may require larger initial doses 100-150mg tid • Clinical improvement (weight gain & ↓in HR) is noted in the first 2-6 wks, with FT4 improvement in the first 2 wks • Once clinical improvement occurs the dose of PTU is ↓by half. Goal to keep FT4 at the upper limit of normal, with least amt of medication • In 30% of pt PTU may be D/C’ed in the last 4 - 8wks of pregnancy (Mestman. Best Practice & Research clin endoMetb.,200,vol 18,no. 2,27-88)

  45. CENTRAL CONGENITAL HYPOTHYROIDISM • Uncontrolled maternal hyperthyroidism • High levels of serum T4 in maternal circulation cross placental barrier • Feed back to the fetal pituitary with suppression of fetal pituitary TSH • Diagnosis : Neonatal serum FT4 is low & serum TSH is low normal or inappropriate for the level of FT4. In majority of infants there is a return to euthyroidism in a few weeks to months. • Rx with LT4 and long term follow up

  46. Physiologic Changes in Thyroid Function During Pregnancy

  47. Physiologic adaptation during pregnancy • increase in thyroid-binding globulin • secondary to an estrogenic stimulation of TBG synthesis and reduced hepatic clearance of TBG ;two to threefold • levels of bound proteins, total thyroxine, and total triiodothyronine are increased and resin triiodothyronine uptake (RT3U) is decreased • begins early in the first trimester, plateaus during midgestation, and persists until shortly after delivery • decrease in its hepatic clearance,estrogen-induced sialylation • free T4 and T3 increase slightly during the first trimester in response to elevated hCG. decline to nadir in third trimester

  48. human chorionic gonadotropin (hCG) • intrinsic thyrotropic activity • begins shortly after conception, peaks around gestational week 10,declines to a nadir by about week 20 • directly activate the TSH receptor • partial inhibition of the pituitary gland (by cross-reactivity of the α subunit) • transient decrease in TSH between Weeks 8 and 14 • mirrors the peak in hCG concentrations • 20% of normal women, TSH levels decrease to less than the lower limit of normal

More Related