[Thyroid function and thyroid autoimmunity at the late pregnancy: data from 664 pregnant women].

OBJECTIVE: To study the prevalence of thyroid diseases, as well as characteristics of the disease spectrum and thyroid autoimmunity in women at the end of pregnancy. METHODS: Six hundred and sixty-four pregnant women (pregnancy group) and 276 non-pregnant women (control group) were enrolled in the study. Serum thyrotropin (TSH), thyroid peroxidase antibody (TPOAb), free T(3) (FT(3)) and free T(4) (FT(4)) were measured by high-sensitive immunochemiluminescent assay, and urinary iodine was also examined at the end of pregnancy. Overt hyperthyroidism was diagnosed when both TSH < 0.3 mU/L and FT(4) and/or FT(3) levels were elevated. Subclinical hyperthyroidism was diagnosed when TSH < 0.3 mU/L with normal FT(4) and FT(3) levels. The diagnostic criteria for overt hypothyroidism was TSH > 4.8 mU/L accompanied by decreased FT(4), and for subclinical hypothyroidism was TSH > 4.8 mU/L with normal FT(4) and FT(3) levels. RESULTS: (1) The median urinary iodine (MUI) of pregnancy group was 201.5 microg/L, and that of control group was 196.0 microg/L (P > 0.05). Women in the two groups were iodine-adequate. (2) The overall prevalence of thyroid diseases in pregnancy group and control group was 7.8% (52/664) and 6.9% (19/276), respectively (P > 0.05). (3) As for the diseases pattern, there were obvious differences between the two groups. In pregnancy group, the prevalence of hyperthyroidism was lower than that of hypothyroidism (1.1% vs 6.8%, P < 0.01). In control group, the prevalence of hyperthyroidism and hypothyroidism was 4.7% and 2.2%, respectively (P > 0.05). Compared with control group, the prevalence of hyperthyroidism in pregnancy group was much lower (1.1% vs 4.7%, P < 0.01), mainly due to the decrease of overt hyperthyroidism; whereas, the increment of subclinical hypothyroidism resulted in the higher prevalence of hypothyroidism in pregnancy group (6.8% vs 2.2%, P = 0.01). (4) The median TSH level of the healthy women in pregnancy group was significantly higher than that in control group (2.50 vs 1.54 mU/L, P < 0.01). The positive rate of TPOAb in pregnancy women was lower than that in non-pregnancy women (3.3% vs 9.4%, P < 0.01). CONCLUSION: At the end of pregnancy, hypothyroidism accounts for most thyroid diseases. Thyroid autoimmunity is suppressed.

[The dynamic changes of serum Th1 and Th2 cytokines in postpartum thyroiditis].

OBJECTIVE: To investigate the dynamic changes of serum Th1 and Th2 cytokines in patients with postpartum thyroiditis (PPT) during the first postpartum year. METHODS: 21 patients diagnosed as clinical PPT and 11 healthy postpartum women were enrolled in the study. Blood samples were taken before delivery and every 3 months postpartum for testing serum IFNgamma, IL-2, IL-4 and IL-10, which were measured with ELISA method. RESULTS: In patients with PPT, the detection rate of IFNgamma and IL-2 at 6th month postpartum were 19.0% (4/21) and 14.3% (3/21), respectively, being lower than those before delivery [52.4% (11/21) and 61.9% (13/21), respectively, P < 0.05]. The detection rate of IL-4 and IL-10 in patients were 71.4% (15/21) and 95.2% (20/21), respectively. A significant raise when compared with that before delivery (61.9%, 13/21) was seen in IL-10 (P < 0.05). Although Th1 cytokines (IFNgamma, IL-2) declined gradually post-parturition both in healthy postpartum women and PPT patients, yet Th2 cytokines (IL-4, IL-10) showed different tendency in healthy postpartum women and PPT patients. Th2 cytokines declined gradually in healthy postpartum women, while it kept at high level until the 12th month postpartum in the PPT patients. CONCLUSION: In PPT patients, Th2 cytokines show higher levels after delivery. Th2 cells are dominant and protected thyroids from Th1 cells during the course of PPT; this might be helpful to the recovery from disturbance of thyroid autoimmunity.