Management of hypothyroidism in Pregnancy with Armour Thyroid


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Management of hypothyroidism in Pregnancy with Armour Thyroid
Tolulope Shonibare, John Jolly and Alia Munir
Edna Coates Diabetes and Endocrine Centre, Obstetric Unit
Pinderfields General Hospital, Wakefield, UK

Introduction
Armour Thyroid is a brand of desiccated porcine extract which is historical treatment for hypothyroidism. Its use in present day is considered obsolete and has been superseded since the 1960’s by Levothyroxine1.Each grain (60mg) contains 38mcg of levothyroxine and 9mcg of liothyronine 2. Due to limited clinical effectiveness studies, it is not licensed for use in the united kingdom3. We present a case of armour thyroid use in pregnancy at the patient’s request.

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Fig 1: Picture of Armour thyroid, source; www.healthcare-supplements.blogspot.com

Background

A 33 year old lady was referred to our joint antenatalendocrine clinic at 18 weeks gestation. She was initially diagnosed with primary hypothyroidism in 2010 with strongly positive thyroid peroxidase antibodies six weeks following her first pregnancy. She was then commenced on 125mcg of levothyroxine. Unfortunately treatment with levothyroxine failed to abate her symptoms of lethargy, apathy and weight gain. As result, she commenced a self-prescription with three grains of armour thyroid in 2011. She had a subsequent pregnancy which ended with a miscarriage at six weeks gestation whilst on armour thyroid.
In her third pregnancy, she presented at booking having increased her dose of armour thyroid to three and a half grains. Her TSH was suppressed throughout gestation at <0.02mU/L (0.20-4.00mU/L). Her average free T4 was 12.4pmol/L (9.0-19.0pmol/L) and free T3 6.15pmol/L (2.5-5.7pmol/L). The entire course of pregnancy was uneventful with normal foetal anatomy and interval scans. She delivered a live male foetus at 40 weeks with an unremarkable baby check and heel prick screen.

Table 1

Date
October 2014
December 2014
January 2015
April 2015

TSH (0.20-4.00)
mU/L <0.02*
<0.02*
<0.02*
<0.02*

Free T4 (9.0-19.0)
pmol/L 12.6
12.1
10.7
.
14.2

Free T3 (2.5-
5.7)pmol/L 4.6
6.4*
4.0
9.6*

Table 1; Trend of thyroid results of Armour thyroid in pregnancy

Fig 2: Armour thyroid grain, source; www.webmd.com
Discussion
Armour thyroid is not recommended for treatment of hypothyroidism in the U.K 4. However patients are still able to obtain prescriptions over the internet. Other forms of desiccated thyroid extract also exist and there have been controversies in the literature as to whether they should be recommended for treatment of hypothyroidism .5,6 There are safety concerns regarding excessive amounts of T3 relative to T4, which is inconsistent with normal physiology. Dosing can be challenging as this is largely based on patients symptoms rather than on laboratory values, however the potential side effects could mirror that of untreated hyperthyroidism .4,7 In pregnancy, the potential risk to both mother and fetus are unknown. Moreover compared to levothyroxine, it is not regarded as a pure preparation of thyroid hormone with the possibility . of dosage variability between batches. Our patient’s TSH was suppressed throughout pregnancy, despite being fully aware of the potential risks. Although the outcome was uneventful, this case posed an ethico-legal challenge balancing patient expectation against recommended practice. Our PubMed search showed no previous publications on use of Armour thyroid in pregnancy, however some cases have been described on on-line patient forums. We do not recommend the use of Armour thyroid for treatment of hypothyroidism.
References
1. British Thyroid Association, Patient information statement on Hypothyroidism and the press 2007. 2. Armour thyroid and combined thyroxine/tri-iodothyronine as Thyroid Hormone replacement. A Statement from the British Thyroid Association Executive Committee,
February 2007 3. What clinical evidence is there to support the use of “Armour thyroid” or desiccated thyroid extract, UK Medicines information (UKMI) pharmacists for NHS healthcare
professionals, London Medicines information service, 2014 4 The diagnosis and management of primary hypothyroidism. Royal College of Physicians 5 J.C Lowe, Stability, Effectiveness and safety of Desiccated thyroid vs Levothryoxine: A rebuttal to the British Thyroid Association:Thyroid Science 4(3\0:C1-12,2009 6 Hoang TD,Olsen CH,Mai VQ et al. Dessicated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized double-blind, crossover
study. J Clin Endocrinol Metab 2013;98(5) ;1982-1990 7 Baisier WV, Hertoghe J, Eeckhaut W. Thyroid Insufficiency. Is thyroxine the only valuable drug? Nutr Environ Med 1997;11:159-166

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Management of hypothyroidism in Pregnancy with Armour Thyroid