Abstract
In healthy subjects there are changes in thyroid function during pregnancy consequent on the increased synthesis of TBG and the thyroid stimulating effect of hCG. Serum thyroid hormones are elevated in the first trimester but fall during the latter half of pregnancy. Iodine deficiency may accentuate these changes. Hyperemesis gravidarum is associated with elevated thyroid hormone values due to high hCG levels in a third of patients. Hyperthyroidism in pregnancy is usually due to Graves’ disease and is best managed with doses of antithyroid drugs sufficient to maintain euthyroidism. There is no evidence of damage to the fetus by this regime and breast feeding can be allowed. Beta adrenoreceptor blocking agents should not be used on a long-term basis. Hypothyroidism in pregnancy is associated with an adverse outcome in fetal health as well as an increase in obstetric complications. While treatment is eventually the same as for a non-pregnant person, there is evidence that the dose of L-thyroxine may require adjustment during pregnancy. Increasing L-thyroxine requirements, based on measurements of maternal L-T4 values have been noted by some but not all investigators. Women presenting in pregnancy with untreated hypothyroidism should be allowed to continue to term preferably with L-T4 replacement. The neonatal thyroid status should be assessed carefully in babies from mothers who have had either hyper- or hypothyroidism in pregnancy. Transplacental passage of maternal antibodies may cause neonatal hyperthyroidism or be associated with transient neonatal hypothyroidism.
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Glinoer D., De Nayer P., Bourdoux P., Lemone M., Robyn C., Van Steirteghem A., Kinthaert J., Lejeune B. Regulation of maternal thyroid during pregnancy. J. Clin. Endocrinol. Metab. 71: 276, 1990.
Ballabio M., Poshyachinda M., Ekins R.P. Pregnancy-induced changes in thyroid function: role of human chorionic gonadotropin as putative regulator of maternal thyroid. J. Clin. Endocrinol. Metab. 73: 824, 1991.
Ekins R. Measurement of free hormones in blood. Endocr. Rev. 11: 5, 1990.
Yoshimura M., Nishikawa M., Horimoto M., Yoshikawa N., Sawaragi S., Horikoshi Y., Sawaragi I., Inada M. Thyroid stimulating activity of human chorionic gonadotropin in sera of normal pregnant women. Acta Endocrinol. 123: 277, 1990.
Hoermann R., Ott M., Salier B., Lobig H., Schatz H., Mann K. Relationship between human chorionic gonadotropin and thyroid function in normal pregnancy. In: Beckers C., Reinwein D. (Eds.), The thyroid and pregnancy. Schattauer, Stuttgart, 1991, p. 65.
Niswander K.R., Gordon M. The women and their pregnancies. W.B. Saunders Co., Philadelphia, 1972, p. 246.
Swaminathan R., Chin R.K., Lao T.T.H., Mak Y.T., Panesar N.S., Cockram C.S. Thyroid function in hyperemesis gravidarum. Acta Endocrinol. 120: 155, 1989.
Goodwin T.M., Montoro M., Mestman J.H., Perkari A.E., Hershman J.M. The role of chorionic gonadotropin in transient hyperthyroidism of hyperemesis gravidarum. Trans. Ass. Am. Phys. 104: 223, 1991.
Munro D.S., Dirmikis S.M., Humphries H., Smith T., Broadhead G.D. The role of thyroid stimulating immunoglobulins of Graves’ disease in neonatal thyrotoxicosis. Br. J. Obstet. Gynaecol. 85: 837, 1978.
Messer P.M., Hauffa P., Olbricht T., Benker G., Kotulla P., Reinwein D. Antithyroid drug treatment of Graves’ disease in pregnancy: Long-term effects on somatic growth, intellectual development and thyroid function of the offspring. Acta Endocrinol. 123: 311, 1990.
McCarroll A.M., Hutchinson M., McAuley R., Montogomery D.A.D. Long-term assessment of children exposed in utero to Carbimazole. Arch. Dis. Child. 51: 532, 1976.
Burrow G.N., Klatskin E.H., Genel M. Intellectual development in children whose mothers received propylthiouracil during pregnancy. Yale J. Biol. Med. 57: 151, 1978.
Montoro M., Collea J., Frasier S.D., Jorge H., Mestman M.D. Successful outcome of pregnancy in women with hypothyroidism. Ann. Intern. Med. 94: 31, 1981.
Burrow G.N. Thyroid disease in pregnancy. In: Burrow G.N., Oppenheimer J.H., Volpe R. (Eds.), Thyroid function and disease. Saunders Co., Philadelphia, 1990.
Martinez-Frias M.L., Cereijo A., Rodriguez-Pinilla E., Urioste M. Methimazole in animal feed and congenital aplasia cutis. Lancet 339: 742, 1992.
Man E.B., Shaver B.A., Cooke R.E. Studies of children born to women with thyroid disease. Am. J. Obstet. Gynecol. 75: 728, 1958.
Man E.B., Jones W.S. Thyroid function in human pregnancy. V. Incidence of maternal serum low butanol-extractable iodines and of normal gestational TBG and TBPA capacities; retardation of 8 month old infants. Am. J. Obstet. Gynecol. 104: 898, 1969.
Man E.B., Holden R.H., Jones W.S. Thyroid function in human pregnancy. VII. Development and retardation of 4 year old progeny of euthyroid and of hypothyroxinemic women. Am. J. Obstet. Gynecol. 109: 12, 1971.
Echt C.R., Doss J.F. Myxedema in pregnancy. Obstet. Gynecol. 22: 6154, 1963.
Potter J.D. Hypothyroidism and reproductive failure. Surg. Gynecol. Obstet. 150: 251, 1980.
Davis L.E., Leveno K.J., Cunningham G.F. Hypothyroidism complicating pregnancy. Obstet. Gynecol. 72: 108, 1988.
Mandell S.J., Reed Larsen P., Seely E.W., Brent G.A. Increased need for thyroxine during pregnancy in women with primary hypothyroidism. N. Engl. J. Med. 323: 91, 1990.
Girling J.C., de Swiet M. Thyroxine dosage during pregnancy in women with primary hypothyroidism. Br. J. Obstet. Gynaecol. 99: 368, 1992.
Lazarus J.H., Othman S. Thyroid disease in relation to pregnancy. Clin. Endocrinol. 34: 91, 1991.
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Lazarus, J.H. Treatment of hyper- and hypothyroidsm in pregnancy. J Endocrinol Invest 16, 391–396 (1993). https://doi.org/10.1007/BF03348864
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DOI: https://doi.org/10.1007/BF03348864