The impact of maternal hypothyroidism during pregnancy on neonatal outcomes: a systematic review and meta-analysis

Abstract

The effects of maternal hypothyroidism on neonatal outcomes were not definitely confirmed. We conduct a systematic review of the literatures on the impact of maternal hypothyroidism on neonatal outcomes. We searched Pubmed, Embase and the Cochrane Controlled Trials Register databases complemented by manual searches in article references without language restrictions published from 1946 to April 2015. Nine trials are included. For preterm birth in pregnancies of hypothyroidism women, there is an increased tendency (RR 1.18; 95% CI 0.99 to 1.40; p = 0.06). The same result is seen relating to the low birth weight (RR 1.31; 95% CI 1.00 to 1.72; p = 0.05). Regarding small for gestational age there is no significant increase. Children who were born from mothers with hypothyroidism during pregnancy have increased birth weight (MD 32.35, 95% CI 7.46 to 57.24; p = 0.01). The impact of maternal hypothyroidism shows a trend of reduced risk of large for gestational age (RR 1.17; 95% CI 0.99 to 1.38; p = 0.06). Our review suggests that mothers with hypothyroidism during pregnancy are more likely to give birth to children with higher birth weight or LGA, and L-T4 supplementation should be recommended. The risk of preterm birth and low birth weight also tends to be higher in children with hypothyroidism mothers.

Chinese abstract

母体甲状腺功能低下对新生儿结局的影响尚未得到完全的证实。我们对母体甲状腺功能低下对新生儿影响的文献进行了系统的回顾性研究。我们检索了Pubmed、Embase和Cochrane对照试验注册数据库，并通过手工检索文章的参考文献作为补充，这些文献从1946年到2015年4月，没有语言限制。共包括九个试验。甲状腺功能低下的妇女怀孕，早产有增加的趋势（RR 1.18；95% CI 0.99∼1.40；P = 0.06）。同样的结果也见于与低出生体重的关系（RR 1.31；95% CI 1∼1.72；P = 0.05）。小于胎龄儿没有明显增加。妊娠期甲状腺功能低下的母亲所生的孩子出生体重增加（MD32.35，95% CI 7.46∼57.24; p=0.01)。大于胎龄儿受母亲甲状腺功能低下的影响呈下降的趋势（RR 1.17；95% CI 0.99∼1.38；P = 0.06）。我们的回顾性研究表明：妊娠期合并甲状腺功能低下的母亲更容易生育高出生体重儿或大于胎龄儿，应建议补充左旋甲状腺素。母亲如合并甲状腺功能低下，其胎儿早产和低出生体重的风险也有增加的趋势。

• Birth weight
• hypothyroidism
• neonatal outcomes
• pregnancy

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Declaration of interest

The authors report no declarations of interest. The authors alone are responsible for the content and writing of the article.