Natural changes of maternal thyroid function among women with subclinical thyroid dysfunction and euthyroid women during pregnancy
10.3760/cma.j.issn.1007-9408.2014.10.008
- VernacularTitle:亚临床甲状腺功能障碍孕妇妊娠期甲状腺功能的自然变化趋势
- Author:
Chunfang WANG
;
Huan XU
;
Xiaotian LI
;
Haidong CHENG
;
Xiaoyan LIU
- Publication Type:Journal Article
- Keywords:
Pregnancy complications;
Hypothyroidism;
Hyperthyroidism;
Thyrotropin;
Triiodothyronine;
Thyroxine;
Reference values
- From:
Chinese Journal of Perinatal Medicine
2014;17(10):689-695
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the natural changes of maternal thyroid function among women with subclinical thyroid dysfunction and euthyroid women during pregnancy.Methods A total of 4 042 singleton pregnant women received routine antenatal care in the Obstetrics and Gynecology Hospital of Fudan University between April and November 2012 were enrolled.Thyroid-stimulatinghormones (TSH),freetriiodothyronine (FT3) and free thyroxine (FT4) of 7 136 samples from 4 042 singleton pregnant women were tested at 8-12+6,13-19+6,20-27+6,and 28-40 weeks of gestation and were used to establish the normal gestationalspecific reference values of thyroid function.Among 3 895 women having thyroid function tested at 8-19+6 weeks of gestation with negative thyroid antibodies,there were 93 cases of subclinical hyperthyroidism,91 cases of subclinical hypothyroidism (SCH),three cases of hyperthyroidism and 3 708 cases euthyroid.There were 1 118 women [1 607 euthyroid cases,17 cases of subclinical hypothyroidism (SCH) and 34 cases of subclinical hyperthyroidism] had thyroid function retested at 20-27+6 and 28-40 weeks of gestation,and without medicinal intervention.Analysis of variance and LSD test were used to analyze the changes of maternal thyroid function.Results (1) The reference ranges of TSH at 8-12+6,13-19+6,20 27+6 and 28-40 weeks of gestation [median (Pz5-P97.5)] were 1.32 (0.03-4.17),1.83 (0.19-4.94),2.27 (0.70-5.42) and 2.34 (0.63-5.52) mU/L respectively.(2) Without medicinal intervention,thyroid function became normal in 80％ (45/56) SCH women at 20-27+6 weeks,but 20％ (9/45) of them developed SCH again at 28-40 weeks.The thyroid function became normal in 75％ (70/93) women with subclinical hyperthyroidism at 20-27+6 weeks,but in 15％ (14/93) of them,thyroid function remained abnormal at 28-40 weeks.9.40％ (30/319) and 6.25％ (21/336) euthyroid women with TSH ≥ 3 mU/L at 8-19+6 weeks of gestation developed SCH at 20-27+6 weeks and 28-40 weeks,while 0.42％ (5/1 202) and 0.86％ (10/1 163) euthyroid women with TSH ＜3 mU/L had SCH.1.66％ (20/1 202) and 1.98％ (23/1 163) euthyroid women with TSH＜3 mU/L at 8-19+6 weeks of gestation developed subclinical hyperthyroidism at 20-27+6 weeks and 28-40 weeks of gestation.(3) In comparison between 8-19+6 weeks and 20-27+6 weeks of gestation,TSH levels increased by (0.47±0.03) mU/L in euthyroid women,and more significantly in subclinical hyperthyroidism women [(0.82±0.06) mU/L],but decreased by (1.67±0.25) mU/L in SCH women (LSD test,all P＜0.05).The FT3 levels decreased by (0.47±0.02) pmol/L in euthyroid women,and more significantly in subclinical hyperthyroidism and SCH groups [(1.02± 0.18) and (0.72±0.08) pmol/L,LSD test,all P＜0.05].FT4 decreased by (2.31 ±0.04) pmol/L in euthyroid women,and more significanly in subclinical hyperthyroidism women [(4.63± 0.62) pmol/L] (LSD test,P＜0.05),but the decrement in SCH group [(1.78±0.28) pmol/L] was similar to euthyroid women (LSD test,P＞0.05).There were no significant differences in changes of TSH,FT3 and FT4 at 20-27+6 weeks and 28-40 weeks among euthyroid women,SCH and subclinical hyperthyroidism groups (F=1.01,1.14 and 2.04,all P＞0.05).Conclusions Women with subclinical thyroid dysfunction with negative thyroid antibodies experience significantly different natural changes when compared with euthyroid women,especially before 28 weeks of gestation.
