Management of hyperthyroidism in pregnancy
DOI:
https://doi.org/10.18203/2320-1770.ijrcog20151598Keywords:
Hyperthyroidism, Pregnancy, Carbimazole, Prophyl thio uracilAbstract
Hyperthyroidism in pregnancy is associated with adverse foetal, maternal and obstetrical outcome. Untreated or inadequately treated hyperthyroidism may precipitate pre eclampsia and congestive cardiac failure in mother. It also increases the risk of miscarriage, abruption placentae and premature delivery in such patients. Maintaining euthyroidism in these patients is of utmost importance. Antithyroid medications are used as first line treatment for such patients to restore euthyroid status at the earliest. Radioactive iodine is absolutely contraindicated in pregnancy and surgery often requires pre-treatment with anti thyroid medications. Two drugs are available –carbimazole and propylthiouracil. Use of carbimazole/methimazole in pregnancy is not only associated with increased incidence of scalp defect(aplasia cutis ) in the infants, but some specific congenital malformation like choanal atresia, oesophageal atresia, trachea-oesophageal fistula, patent vitello intestinal duct, omphalocele, dysmorphic facial features and growth retardation do occur. These malformations represent carbimazole /methimazole embryopathy. Due to the association of foetal teratogenicity with carbimazole /methimazole, propylthiouracil is recommended as the drug of choice in first trimester of pregnancy. However, as its use is associated with risk of hepatotoxicity, it should be changed to carbimazole/methimazole thereafter.
References
Glinoer D. Thyroid hyperfunction during pregnancy. Thyroid. 1998;8(9):859-64.
Cooper DS, Lauberg P. Hyperthyroidism in pregnancy. The Lancet Diabetes &endocrinology. 2013;3:238-49.
Aggarwal N, Suri V, Singhla R, Chopra S, Shikha P, Bhansali A. Pregnancy outcome in hyperthyroidism case control study. Gynecol Obstet Invest, 2014.
Milliar LK, Wing DA, Leung AS, Koonings PP, Montoro MN, Mestman JH. Low birth weight and pre eclampsia in pregnancies complicated by hyperthyroidism. Obstet Gynecol. 1994;84(6):946-9.
Momotani N, Noh J, Oyanagi H, Ishikawa N. Anti thyroid drug therapy for Graves’ disease during pregnancy: optimal regimen for foetal thyroid status. N Eng J Med. 1986;315(1):24-8.
Alzahrani AS,Ceresini G,Aldasougi SA. Role of ultrasonography in the differential diagnosis of thyrotoxicosis: a non invasive, cost effective and widely available but underutilized diagnostic tool. Endocr Pract. 2012;18:567-78.
Albar MT, Adam JM. Gestational transient thyrotoxicosis .Acta Med Indones. 2009;41:99-104.
Brodsky JB, Cohen EN, Brown BW, Wu ML, Whitcher C. Surgery during pregnancy and fetal outcome. American Journal of Obstetrics and Gynecology. 1980;138:1165-7.
Redmond GP. Propanolol and fetal growth monitoring. Semianars in Perinatology. 1982;6:142-7.
Yoshimura Noh J, Watanabe N, Iwaku K, Kobayashi S, Suzuki M, Ohye H, et al. Frequency of Adverse Events of Antithyroid Drugs Administered during Pregnancy. 2014 Journal of Thyroid Research. doi.org/10.1155/2014/952352.
Tajiri J, Noguchi S. Antithyroid drug induced agranulocytosis: special reference to normal white blood cell count. Thyroid. 2004;14:459-62.
Liaw YF, Huang MJ, Fan KD. Hepatic injury during propylthiouracil therapy in patients with hyperthyroidism. A cohort study. Annals of Internal Medicine. 1993;118:424-8.
Guston LE, Steil J, Caterson RJ. Anti thyroid drugs and anti neutrophil cytoplasmic antibody positive vasculitis: a case report and review of literature. J Clin Endocrinol Metab. 1999;84:13-6.
Foulds N, Walpole I, Elmslie F, Mansour S. Carbimazole embryopathy: an emerging phenotype. American Journal of Medical Genetics. 2005;132(2):130-5.
Myers AK, Reardon W. Choanal atresia - a recurrent feature of foetal carbimazole syndrome. Clinical Otolaryngology. 2005;30:364-83.
Wing DA, Millar LK, Koonings PP, Montoro MN, Mestman JH. A comparison of propylthiouracil versus methimazole in the treatment of hyperthyroidism in pregnancy. Am J Obstet Gynecol. 1994;170:90-5.
Cooper DS, Rivkess SA. Putting Propylthiouracil in perspective. J Clin Endo Metab. 2009;6:1881-2.
Rosenfeld H, Asher Ornoy, Svetlana Shechtman. Pregnancy outcome, thyroid dysfunction and fetal goitre after in utero exposure to propylthiouracil: a controlled cohort study. Br J Clin Pharmacol. 2009;68(4):609-17.
Batra CM. Fetal and neonatal thyrotoxicosis. Indian J Endocr Metab. 2013;17:50-4.
Radetti G, Zavallone A, Gentili L.Fetal and neonatal thyroid disorder. Minerva Pediatrica. 2002;54:383-400.
Skuza KA. Prediction of neonatal hyperthyroidism in infants born to mothers with Graves`disease. J Pediatr. 1996;128:264-8.
