Thyroid hormones status during pregnancy in normal Iranian women
Tóm tắt
Pregnancy is associated with significant, but reversible changes in thyroid function studies, which are among the most profound seen as a result of a normal physiologic state. The present study was carried out to find out alterations in thyroid function tests in each trimester in normal pregnant women as compared to non-pregnant women in Tabriz-Iran. A case-control study designed with 229 normal pregnant women that randomly selected from the first (64 samples), the second (92 samples), and the third (73 samples) trimesters and 250 randomly selected non-pregnant healthy female controls. Age range in both groups was 16–40 years. Thyroid function tests carried out by measuring serum levels of thyroid stimulating hormone (TSH), free and total thyroxin (FT4, TT4), and free and total triiodothyronine (FT3, TT3) by commercially available radio immunoassay kits. We found that mean TT4 increased progressively during pregnancy. Our study showed increasing in serum levels of TT3 in the second trimester and then declining during the third trimester compared with non-pregnant women. We showed that FT4 strongly decreased during the third trimester. Free T3 showed declining in the second and third trimesters. Mean TSH did not show significant difference in each trimester compared with non-pregnant women. The thyroid function tests in pregnancy should be interpreted against gestational age-related reference intervals to avoid mis-interpretation of thyroid function during pregnancy.
Tài liệu tham khảo
Guillaume, J., Schussler, G.C. and Goldman, J. (1985) Components of the total serum thyroid hormone concentrations during pregnancy: high free thyroxine and blunted thyrotropin (TSH) response to TSH-releasing hormone in the first trimester. J. Clin. Endocrinol. Metab. 60, 678–684.
Glinoer, D., de Nayer, P., Bourdoux, P., Lemone, M., Robyn, C., van Steirteghem, A., Kinthaert, J. and Lejeune, B. (1990) Regulation of maternal thyroid during pregnancy. J. Clin. Endocrinol. Metab. 71, 276–287.
Burrow, G.N. (1993) Thyroid function and hyperfunction during gestation. Endocr. Rev. 14, 194–202.
Burrow, G.N., Fisher, D.A. and Larsen, P.R. (1994) Maternal and fetal thyroid function. N. Engl. J. Med. 331, 1072–1078.
Brent, G.A. (1997) Maternal thyroid function: interpretation of thyroid function tests in pregnancy. Clin. Obstet. Gynecol. 40, 3–15.
Lacka, K. and Lakoma H. (2002) Thyroid gland and pregnancy—physiology and pathology. Wiad. Lek. 55, 450–462.
Fantz, C.R., Dagogo-Jack, S., Ladenson, J.H. and Gronowski, A.M. (1999) Thyroid function during pregnancy. Clin. Chem. 45, 2250–2258.
Khandakar, M.A., Ali, M.S. and Kahtun, M. (2002) Thyroid status of normal pregnant women in Dhaka City. Mymensingh. Med. J. 1, 1–5.
Mulder, J.E. (1998) Thyroid diseases in women. Med. Clin. N. Am. 82, 103–125.
Haddow, J.E., Palomaki, G.E., Allan, W.C., Williams, J.R., Knight, G.J., Gagnon, J.et al. (1999) Maternal thyroid deficiency during pregnancy and subsequent neuropsychological development of the child. N. Engl. J. Med. 341, 549–555.
Goodwin, T.M., Montoro, M., Mestman, J.H., Pekary, A.E. and Hershman, J.M. (1992) The role of chorionic gonadotropin in transient hyperthyroidism of hyperemesis gravidarum. J. Clin. Endocrinol. Metab. 75, 1333–1337.
Lockitch, G. (1997) Clinical biochemistry of pregnancy. Crit. Rev. Clin. Lab. Sci. 34, 67–139.
Panesar, N.S., Li, C.Y. and Rogers, M.S. (2001) Reference intervals for thyroid hormones in pregnant Chinese women. Ann. Clin. Biochem. 38, 329–332.
Shah, M.S., Davies, T.F. and Stagnaro-Green, A. (2003) The thyroid during pregnancy: a physiological and pathological stress test. Minerva. Endocrinol. 28, 233–245.
McElduff, A. (1999) Measurement of free thyroxine (T4) levels in pregnancy. Aust. N. Z. J. Obstet. Gynecol. 39, 158–161.
Kumar, A., Gupta, N., Nath, T., Sharma, J.B. and Sharma, S. (2003) Thyroid function tests in pregnancy. Indian. J. Med. Sci. 57, 252–258.
Erem, C., Kavgaci, H., Karahan, C., Mocan, M.Z. and Telatar, M. (2001) Thyroid function tests in pregnant women with and without goiter in the eastern Black Sea region. Gynecol. Endocrinol. 15, 293–297.
Price, A., Obel, O., Cresswell, J., Catch, I., Rutter, S., Barik, S. et al. (2001) Comparison of thyroid function in pregnant and non-pregnant Asian and western Caucasian women. Clin. Chim. Acta. 308, 91–98.