Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan.
Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina.
J Clin Endocrinol Metab. 2018 Apr 1;103(4):1349-1358. doi: 10.1210/jc.2017-01698.
Overt thyroid disease in pregnancy is a known risk factor for abnormal fetal growth and development. Data on the effects of milder forms of variation in maternal thyroid function on intrauterine growth are less well examined.
We explored these associations using repeated thyroid hormone and ultrasound measurements.
DESIGN, SETTING, AND PARTICIPANTS: Data were obtained from 439 pregnant women without diagnosed thyroid disease who were participants in a case-control study of preterm birth nested within an ongoing prospective birth cohort in Boston, Massachusetts.
Ultrasound and delivery indices of fetal growth were standardized to those measured in a larger population.
At median 10, 18, and 26 weeks of gestation, we observed significant inverse associations between free thyroxine (FT4) and birth weight z scores, with the strongest association detected at median 10 weeks, at which time a 10% increase in FT4 was associated with a 0.02 z score decrease (∼8.5 g) in birth weight (β = -0.41 for ln-transformed FT4; 95% confidence interval, -0.64 to -0.18). FT4 was also inversely associated with repeated measurements of estimated fetal weight, head circumference, and abdominal circumference. We observed weaker inverse associations for total T4 and a positive relationship between total triiodothyronine and birth weight z scores. We did not observe any associations for thyroid-stimulating hormone.
In pregnant women without overt thyroid disease, subclinical changes in thyroid function parameters may influence fetal growth.
妊娠期间甲状腺功能亢进是胎儿生长和发育异常的已知危险因素。关于母体甲状腺功能更轻微变化对宫内生长的影响的数据研究较少。
我们使用重复的甲状腺激素和超声测量来探讨这些关联。
设计、地点和参与者：数据来自 439 名未被诊断为甲状腺疾病的孕妇，她们是马萨诸塞州波士顿正在进行的前瞻性出生队列中早产病例对照研究的一部分。
胎儿生长的超声和分娩指标被标准化为更大人群中测量的指标。
在妊娠 10、18 和 26 周的中位数时，我们观察到游离甲状腺素（FT4）与出生体重 z 分数之间存在显著的负相关，在妊娠 10 周的中位数时，这种关联最强，此时 FT4 增加 10%与出生体重的 z 分数降低 0.02 分（约 8.5 克）有关（ln 转换后的 FT4 的β值为-0.41；95%置信区间，-0.64 至-0.18）。FT4 还与估计胎儿体重、头围和腹围的重复测量值呈负相关。我们观察到总 T4 的负相关较弱，总三碘甲状腺原氨酸与出生体重 z 分数之间存在正相关。我们没有观察到促甲状腺激素的任何关联。
在没有明显甲状腺疾病的孕妇中，甲状腺功能参数的亚临床变化可能会影响胎儿生长。
