Do elevated thyrotropin levels increase the risk of miscarriages: yes or no?

Abstract

Background

To examine correlation between elevated levels of thyrotropin with the frequency of miscarriages.

Methods

A cross-sectional study was conducted on the 380 respondents and it investigated TSH (thyrotropin), thyroid peroxidase antibody(anti-TPO) and free thyroxine (FT4) in pregnant women who had a miscarriage (N = 179) and pregnant women with normal pregnancies (N = 201).

Results

The incidence of subclinical hypothyroidism in the miscarriages group was higher than in control group (61.4% vrs 15.79% (p < 0.001). In the miscarriages group with hypothyroidism (first trimester) mean value of TSH was significantly higher 4.31 ± 2.55 mIU/L compared to the control group 1.95 ± 0.86mIU/L (p < 0.001). Logistic multivariate regression revealed that TSH and body mass index (BMI) have a significant influence on the miscarriage; TSH level has a higher odds ratio (OR) 1.47 CI (95% 1.22–1.78) than BMI (OR) 1.14 CI (95% 1.06–1.23)) (p < 0.001). The combination of thyroid autoimmunity and TSH > 2.5mIU/L increase the risk of miscarriage (65.75%) compared to positive anti-TPO antibodies and TSH < 2.5mIU/L(14.15%)(p < 0.001).

Conclusions

Higher TSH levels correspond with obesity during early pregnancy and may be a sign of maternal thyroid dysfunction. Physiological thyroid function in the first trimester of pregnancy is important for perinatal outcome.

摘要

背景：探讨促甲状腺激素水平升高与流产频率之间的相关性。

方法：对380名受访者进行了横断面研究, 并调查了有流产史的孕妇（N=179）和正常妊娠的孕妇（N=201）的TSH（促甲状腺激素）、甲状腺过氧化物酶抗体（抗TPO）和游离甲状腺素（FT4）。

结果：流产组亚临床甲状腺功能减退症发生率高于对照组（61.4% vs15.79%（P<0.001）。孕早期流产组TSH平均值4.31±2.55 mIU/L显著高于对照组的1.95± 0.86 mIU/L。 Logistic多因素回归分析显示, TSH和体重指数（BMI）对流产有显著影响, TSH水平的OR值1.47 （95%CI为1.22-1.78）高于BMI的OR值1.14（95%CI为1.06-1.23）（p<0.001）。甲状腺自身免疫和TSH > 2.5mIU/L组合的流产风险（65.75%）高于抗TPO抗体阳性和TSH < 2.5mIU/L组合的流产风险（14.15%）（p<0.001）。

结论：高TSH水平与妊娠早期肥胖相对应, 可能是母亲甲状腺功能异常的一个标志, 孕早期甲状腺生理功能对围生儿结局非常重要。

Keywords:

• Subclinical hypothyroidism
• thyrotropin
• antibodies to thyroidperoxidase
• miscarriages
• screening

Acknowledgments

We would like to express our gratitude to all those who helped us during the writing of this manuscript. Thanks to all the peer reviewers for their opinions and suggestions.

Ethics approval and consent to participate

This prospective study was conducted following all ethical principles of the Department of Gynaecology and Obstetrics of the University Clinical Hospital Mostar. This study was approved by the Ethics Committee of the Clinical Hospital Centre Mostar and valid documentation exists for this matter (ref.no.:2053/14 of 3^rdApril2014).

Disclosure statement

No conflict of interest.