妊娠晚期亚临床甲状腺功能减退症对妊娠结局的影响

Effects of maternal subclinical hypothyroidism diagnosed in the third trimester on pregnancy outcomes

目的探讨妊娠晚期亚临床甲状腺功能减退症（subclinical hypothyroidism，SCH）对妊娠结局及新生儿甲状腺功能的影响。方法2012年1月1日至12月31日在南京医科大学附属常州妇幼保健院产前检查的妊娠晚期（妊娠28～42周）孕妇10695例纳入研究。采用电化学发光技术检测孕妇甲状腺激素水平，随访妊娠结局。时间分辨荧光分析法检测新生儿甲状腺激素水平。采用t检验和x^2检验比较SCH和甲状腺功能正常孕妇、SCH孕妇中甲状腺过氧化物酶抗体阳性（40例）和阴性孕妇（176例）的妊娠结局差异。结果SCH发生率为2．02％（216／10695），SCH孕妇中甲状腺过氧化物酶抗体阳性率为18．5％（40／216）.新生儿未检出甲状腺功能异常。甲状腺功能正常孕妇共7757例，从中按年龄匹配随机抽取222例孕妇作为正常组。与正常组相比，SCH组胎膜早破[28．7％（62／216）与14．9％（33／222），x^2=12．34]、妊娠合并贫血[11．6％（25／216）与4．1％（9／222），x^2=8．65]、妊娠期高血压疾病[9．7％（21／216）与4．5％（10／222），x^2=4．53]、早产[8．8％（19／216）与3．6％（8／222），x^2=5．10]、妊娠期肝内胆汁淤积症的发生率[8.3％（18／216）与2.3％（5／222），x^2=8．14]较高（P值均〈0．05）.SCH组总体不良妊娠结局发生率也高于正常组[69．4％（150／216）与49．5％（110／222），x^2=17．96，P〈0．01]。SCH组中甲状腺过氧化物酶抗体阳性者胎儿生长受限和死产的发生率高于阴性者[7．5％（3／40）与0．0％（0／176），x^2=13．32，P〈0．01；2．5％（1／40）与0．0％（0／176），x^2=4．40，P〈0．05），但总体不良妊娠结局发生率与阴性者比较，差异无统计学意义[65．0％（26／40）与70．5％（124／176），x^2=0．46，P=0．50]。结论妊娠晚期SCH可增加不良妊娠结局发生风险，建议于妊娠早期进行甲状腺功能筛查。

Objective To investigate the incidence of subclinical hypothyroidism （ SCH ） during the third trimester of pregnancy and its effects on pregnancy outcomes and neonatal hypothyroidism. Methods A total of 10 695 women in the third trimester of pregnancy （ 28-42 weeks of gestation ） who labored from January 1, to December 31, 2012 in Changzhou Maternal and Child Health Care Hospital Affiliated to Nanjing Medical University were enrolled. The levels of thyroid stimulating hormone （ TSH ） , free thyroxine （ FT4 ） and thyroid peroxidase antibody （ TPOAb ） of the mothers were quantified by electrochemical immunoassay. The time- resolved fluorescence immunoassay was used to detect neonatal thyroid hormone levels. Using t test or ;（2 test, the incidence of adverse pregnancy outcomes was compared between SCH group and euthyroid group and between SCH women with positive （n=40） or negative TPOAb （n=176） . Results The incidence of SCH was 2.02% （ 216/10 695 ） and the positive rate of TPOAb in SCH women was 18.5% （ 40/216 ）. Noneonatal thyroid dysfunction was found. According to the age matched, 222 cases were randomly selected as controls from 7 757 euthyroid women. Compared with the controls, SCH women had a higher incidence of premature rupture of membranes [28.7% （ 62/216 ） vs 14.9% （ 33/222 ） ,x^2=12.34], anemia [11.6% （ 25/216 ） vs 4.1% （ 9/222 ） ,x^2=8.65], pregnancy-induced hypertension [9.7% （ 21/216 ） vs 4.5% （ 10/222 ） , x^2=4.53], premature labor [8.8% （ 19/216 ） vs 3.6% （ 8/222 ） , x^2=5.10] and intrahepatic cholestasis of pregnancy [8.3% （ 18/216 ） vs 2.3% （ 5/222 ） ,x^2=8.14] （ all P〈0.05 ） . The overall incidence of adverse pregnancy outcomes was also higher in SCH group than in the controls [69.4% （ 150/216 ） vs 49.5% （ 110/222 ） x^2=17.96, P〈0.01]. The incidence of fetal growth restriction and still birth in SCH mothers with positive TPOAb was higher than in those with negative TPOAb [7.5% （ 3/40 ） vs 0.0% （ 0/176 ） , x^2=13.32, P〈0.01; 2.5% （ 1/40 ） vs 0.0% （ 0/176 ） , x^2=4.40, P〈0.05], but there was no significant difference in the overall incidence of adverse pregnancy outcomes compared with TPOAb-negative mothers [65.0% （ 26/40 ） vs 70.5% （ 124/176 ） , X2=0.46, P=0.50]. Conclusions SCH diagnosed in the third trimester may lead to adverse pregnancy outcomes. Early screening for thyroid dysfunction is necessary.