León Gemma, Murcia Mario, Rebagliato Marisa, Álvarez-Pedrerol Mar, Castilla Ane M, Basterrechea Mikel, Iñiguez Carmen, Fernández-Somoano Ana, Blarduni Elizabeth, Foradada Carles M, Tardón Adonina, Vioque Jesús
Pharmacy, University Cardenal Herrera-CEU, Valencia, Spain.
Paediatr Perinat Epidemiol. 2015 Mar;29(2):113-22. doi: 10.1111/ppe.12172. Epub 2015 Jan 7.
Maternal clinical thyroid disorders can cause reproductive complications. However, the effects of mild thyroid dysfunctions are not yet well established. The aim was to evaluate the association of maternal thyroid function during the first half of pregnancy with birthweight and preterm delivery.
We analysed data on 2170 pregnant women and their children from a prospective population-based cohort study in four Spanish areas. Mid-gestation maternal serum and urine samples were gathered to determine thyroid-stimulating hormone (TSH), free thyroxine (fT4 ), and urinary iodine concentration (UIC). Thyroid status was defined according to percentile distribution as: euthyroid (TSH and fT4 >5th and <95th percentiles); hypothyroxinaemia (fT4 < 5 th percentile and TSH normal), hypothyroidism (TSH > 95th percentile and fT4 normal or <5th percentile), hyperthyroxinaemia (fT4 > 95 th percentile and TSH normal), and hyperthyroidism (TSH < 5 th percentile and fT4 normal or >95th percentile). Response variables were birthweight, small and large for gestational age (SGA/LGA), and preterm delivery.
An inverse association of fT4 and TSH with birthweight was found, the former remaining when restricted to euthyroid women. High fT4 levels were also associated with an increased risk of SGA [odds ratio, 95% confidence interval (CI) 1.28 (95% CI 1.08, 1.51)]. Mean birthweight was higher in the hypothyroxinaemic group (β = 109, P < 0.01). Iodine intake and UIC were not associated with birth outcomes.
High maternal fT4 levels during the first half of pregnancy were related to lower birthweight and increased risk of SGA newborns, suggesting that maternal thyroid function may affect fetal growth, even within the normal range.
孕妇临床甲状腺疾病可导致生殖并发症。然而，轻度甲状腺功能障碍的影响尚未完全明确。本研究旨在评估妊娠前半期孕妇甲状腺功能与出生体重及早产之间的关联。
我们分析了来自西班牙四个地区一项基于人群的前瞻性队列研究中2170名孕妇及其子女的数据。收集妊娠中期孕妇的血清和尿液样本，以测定促甲状腺激素（TSH）、游离甲状腺素（fT4）和尿碘浓度（UIC）。根据百分位数分布将甲状腺状态定义为：甲状腺功能正常（TSH和fT4>第5百分位数且<第95百分位数）；低甲状腺素血症（fT4<第5百分位数且TSH正常），甲状腺功能减退（TSH>第95百分位数且fT4正常或<第5百分位数），高甲状腺素血症（fT4>第95百分位数且TSH正常），以及甲状腺功能亢进（TSH<第5百分位数且fT4正常或>第95百分位数）。反应变量为出生体重、小于胎龄儿和大于胎龄儿（SGA/LGA）以及早产。
发现fT4和TSH与出生体重呈负相关，在仅纳入甲状腺功能正常的女性时，前者的相关性仍然存在。高fT4水平还与SGA风险增加相关[比值比，95%置信区间（CI）1.28（9%CI 1.08，1.51）]。低甲状腺素血症组的平均出生体重较高（β=109，P<0.01）。碘摄入量和UIC与出生结局无关。
妊娠前半期孕妇fT4水平升高与出生体重降低及SGA新生儿风险增加有关，这表明孕妇甲状腺功能可能影响胎儿生长，即使在正常范围内。
