Hamm Michele P, Cherry Nicola M, Martin Jonathan W, Bamforth Fiona, Burstyn Igor
Department of Public Health Sciences, University of Alberta, Edmonton AB.
Department of Medicine, University of Alberta, Edmonton AB.
J Obstet Gynaecol Can. 2009 Nov;31(11):1015-1021. doi: 10.1016/S1701-2163(16)34345-6.
To determine whether maternal hypothyroxinemia during early pregnancy is associated with adverse perinatal outcomes.
Serum samples of a prospective cohort of 879 women collected at 15-16 weeks of pregnancy were analyzed for thyroid-stimulating hormone (TSH) and free thyroxine (T4) concentrations. Women with TSH levels within the normal reference range (0.15-4.0 mU/L) and free T4 levels below the 10th percentile of the sample (8.5 pmol/L) were classified as hypothyroxinemic and were compared with euthyroid women (who had normal TSH and free T4 levels). Thyroid hormone measures were linked to pregnancy outcomes, including small for gestational age (SGA), standardized birth weight z-score, preterm delivery, and Apgar score used as a measure of early neonatal morbidity.
Among 89 hypothyroxinemic women, there was no evidence of an increased risk for fetal growth restriction, preterm birth, or low Apgar score. The relative risk of delivering an SGA infant was 0.38 (95% CI 0.11 to 1.33), the mean difference in birth weight z-score was 0.035 (95% CI -0.17 to 0.24), and the risk of preterm delivery was 0.79 (95% CI 0.38 to 1.67). None of the hypothyroxinemic women gave birth to an infant with a five-minute Apgar score <7. When free T4 levels were substituted for categories of thyroid hormone function, the pattern of results remained unaltered.
Isolated maternal hypothyroxinemia was not observed to have any adverse effect on fetal growth or pregnancy outcome. This study does not provide evidence to support treatment of this condition to prevent fetal growth restriction or neonatal morbidity.
确定孕早期母体甲状腺素水平降低是否与不良围产期结局相关。
对879名孕妇前瞻性队列在妊娠15 - 16周时采集的血清样本进行促甲状腺激素（TSH）和游离甲状腺素（T4）浓度分析。TSH水平在正常参考范围（0.15 - 4.0 mU/L）内且游离T4水平低于样本第10百分位数（8.5 pmol/L）的女性被归类为甲状腺素水平降低，并与甲状腺功能正常的女性（TSH和游离T4水平正常）进行比较。甲状腺激素测量结果与妊娠结局相关，包括小于胎龄儿（SGA）、标准化出生体重z评分、早产以及用作早期新生儿发病率衡量指标的阿氏评分。
在89名甲状腺素水平降低的女性中，没有证据表明胎儿生长受限、早产或低阿氏评分风险增加。分娩SGA婴儿的相对风险为0.38（95%可信区间0.11至1.33），出生体重z评分的平均差异为0.035（95%可信区间 - 0.17至0.24），早产风险为0.79（95%可信区间0.38至1.67）。没有甲状腺素水平降低的女性分娩出5分钟阿氏评分<7的婴儿。当用游离T4水平替代甲状腺激素功能类别时，结果模式保持不变。
未观察到单纯母体甲状腺素水平降低对胎儿生长或妊娠结局有任何不良影响。本研究没有提供证据支持对这种情况进行治疗以预防胎儿生长受限或新生儿发病。
