Aneurin Bevan University Health Board Hyperthyroidism and Hypothyroidism in Pregnancy Guideline N.B. Staff should be discouraged from printing this document. This is to avoid the risk of out of date printed versions of the document. The Intranet should be referred to for the current version of the document. Status: Approved Issue 2 Issue date: June 2017 Approved by: Clinical Effectiveness Forum Review date: June 2019 Owner: Maternity Services Expiry date: June 2020
Contents: 1... Executive Summary 3 1.1 Scope of guideline... 3 1.2 Essential Implementation Criteria... 3 2... Aims 3 3... Responsibilities 3 4... Training 3 5... Monitoring and Effectiveness 3 6... Appendices 3 Page 2 Expiry Date: May 2014
1 Executive Summary This document is a procedure designed to support safe and effective practice 1.1 Scope of guideline This guideline applies to all clinicians working within maternity services 1.2 Essential Implementation Criteria Auditable standards are stated where appropriate 2 Aims To provide support for clinical decision making 3 Responsibilities The Maternity Management team 4 Training Staff are expected to access appropriate training where provided. Training needs will be identified through appraisal and clinical supervision. 5 Monitoring and Effectiveness Local service Improvement Plan will guide monitoring and effectiveness. This policy has undergone an equality impact assessment screening process using the toolkit designed by the NHS Centre Equality & Human Rights. Details of the screening process for this policy are available from the policy owner. 6 Appendices Appendix 1 Appendix1 Management of Hyperthyroidism in Pregnancy (Incidence 1:2000 pregnancies) Maternal risks Weight loss, palpitations Approved 5 by: x increased Maternity Services risk of PET antibodies(trab) Review date: May 2013 Page 3 Expiry Date: May 2014 Placental abruption / fetal loss Thyroid crisis rare but serious Fetal risks Transplacental transfer of maternal Fetal hyperthyroidism, goitre, tachycardia, high output cardiac failure Low birth weight
Antenatal Care o Book into combined ANC: RGH-Monday pm; NHH: Tuesday am o TFTs at booking and 6 weekly thereafter. Treatment titrated to keep free T4 at the upper end of non pregnant range. o TSH receptor antibodies at booking and 28 weeks: if positive and high titres, - monitor fetus for growth, goitre by regular scans and arrange for weekly check of fetal heart rate by community MW for tachycardia and Inform Dr. Sue Papworth, Neonatologist o Anti-thyroid drugs: Prophylythiouracil (PTU) may be used in the 1 st trimester of pregnancy. Check LFT in 3-4 weeks when on PTU- there is a small risk of liver failure. Change to Carbimazole in the 2 nd trimester, there is a small risk of aplasia cutis. o Caution with both drugs: Neutropenia/agranulocytosis- warn about symptoms of infection such as sore throat, fever etc. if present, urgent FBC should be done. o Beta blocker (Propranolol) is used for symptom control such as tachycardia, palpitations, tremor. Long term use can lead to fetal growth restriction and this should be monitored. o Subtotal thyroidectomy is indicated only in those requiring high doses of antithyroid drugs or not tolerating oral medication and is best done in the 2 nd trimester. o Presence of absence of TPO antibodies does not alter the maternal or neonatal outcome. Intrapartum care: Not altered in well controlled hyperthyroidism. There is a risk of Thyroid crisis during labour in uncontrolled hyperthyroidism and this is a medical emergency. Neonatal team should be informed to perform neonatal examination and observe baby on the ward and arrange for baby s blood test for TFTs in 5-10 days. (See flow chart) Postnatal care 1) Decrease the dose of thyroxine to preconception levels after delivery. 2) TFT rechecked 6-8 weeks following delivery with GP. Management of hypothyroidism in pregnancy Incidence: 1% of pregnant women have hypothyroidism Page 4 Expiry Date: May 2014
Implications of hypothyroidism Mother o Miscarriage, fetal loss o Anaemia o Pre- eclampsia o Low birth weight Fetus o Impaired cognitive development in the child Preconception care o Check TFT to ensure Thyroxine dose is adequate (aim to achieve a TSH level of not higher than 2.5mU/l) o Advice to contact GP to check TFT (free T4 and TSH) as soon the pregnancy test is positive for a TFT, as the dose of Thyroxine may need to be increased if TSH >2.5mU/l. Antenatal Care Women with primary hypothyroidism should normally be managed in the general obstetric clinics. At the booking visit, repeat TFT. (Check TSH receptor antibody if patient hypothyroid following treatment for thyrotoxicosis/graves disease, i.e: Thyroidectomy/ radioactive Iodine - these women should be referred to medical antenatal clinic). antenatal clinic. Thyroxine should be titrated to maintain serum TSH concentration not more than 2.5 mu/l in first and < 3mU/l in the second and third trimesters Guide to alteration of dose of thyroxine Serum Increase in TSH thyroxine (mu/l) (µg/day) 2.5-10 25-50 10-20 50-75 >20 100 o Check TFT after 4-6 weeks after change of dose o Otherwise check TFT once every trimester and review in general consultant led clinic with results. o No need for regular growth scans unless clinically indicated. Page 5 Expiry Date: May 2014
ABUHB- Management of babies with maternal history of thyroid disease Pregnant woman with thyroid problems Maternal Hypothyroidism Maternal Hyperthyroidism (Grave s disease) Primary or Autoimmune (Hashimotos) (Clear documentation of cause of hypothyroidism) Post treatment for maternal hyperthyroidism (radioactive iodine ablation/surgery) TRAB Antibody testing at booking and 28 weeks of gestation. No action required TRAB antibody testing during pregnancy (preferably at booking) All TRAB positive women need to be identified and the neonatal team informed prior to delivery If TRAB negative - No action required Babies-to be observed for 48 hours on postnatal ward and follow up in 5-10 days with TFT Page 6 Expiry Date: May 2014