Initiation timing effect of levothyroxine treatment on subclinical hypothyroidism in pregnancy

Abstract

The aim of this study is to estimate the timing impact on levothyroxine replacement among pregnant women with subclinical hypothyroidism (SCH). Ninety-eight pregnant women diagnosed as SCH in the first trimester were randomly divided into three groups: Group A, instantly initiated levothyroxine after diagnosis; Group B, administrated treatment in the second trimester, and Group C, received no prescription. Incidence of pregnancy complications and pregnancy outcomes were compared among three groups and subgroup analysis were performed stratified with TPO status in Group B. Group A exhibited lower rate of pregnancy complications (9.7%) and adverse outcome (3.2%) than Group B (41.9% and 32.3%) and Group C (64.5% and 38.7%). But the late initiation treatment group shared a comparable complication and maternal outcome with untreated women (p = .075 and .596, respectively). After stratified with TPOAb status in Group B, TPOAb⁺ women experienced a remarkable lower complication (14.2%) and adverse outcome rate (7.1%) compared with negative subjects (64.7% and 45%, respectively). Our data suggest that levothyroxine administrated in the first trimester was associated with decreased risk of adverse obstetric event. Additionally, pregnant women with TPOAb positive could also benefit from thyroid hormone therapy even initiated in the second trimester.

Chinese abstract

本研究的目的是评估左旋甲状腺素替代在亚临床甲减的妊娠妇女的时间影响。孕早期诊断亚临床甲减的98例女性随机分到3个组：A组, 在确诊后立即进行左旋甲状腺素的治疗； B组,在孕中期治疗；C组,未进行治疗。比较三组的妊娠并发症、妊娠结局, B组根据甲状腺过氧化物酶(TPO)的结果进行分型。A组的妊娠并发症率(9.7%) 不良结局(3.2%) 低于B组 (41.9% 和32.3%) 和C组 (64.5% 组38.7%)。但是晚治疗组与不治疗组的并发症率和母体结局无统计学差异 (p值分别为.075 and .596) 。在B组根据甲状腺过氧化物酶抗体的结果, 甲状腺过氧化物酶抗体阳性组的女性并发症率 (14.2%) 不良结局率(7.1%) 与甲状腺过氧化物酶抗体阴性组 (64.7%和45%)相比显著偏低。我们的数据显示孕早期开始左旋甲状腺素治疗可以降低不良妊娠事件。而且, 甲状腺过氧化物酶抗体阳性的妊娠女性即使从孕中期开始服药也会受益。

Keywords:

• Subclinical hypothyroidism
• levothyroxine
• adverse outcomes
• TPOAb
• pregnancy

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This study is supported by the grant from Shanghai Jiading District Health and Family Planning Commission (2016-KY-11).