Endocrinology Post-graduation Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Thyroid Section, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Thyroid. 2020 Dec;30(12):1792-1801. doi: 10.1089/thy.2019.0462. Epub 2020 Jul 1.
Insufficient or excessive iodine intake during gestation may compromise adaptive mechanisms in maternal thyroid function and lead to adverse pregnancy outcomes. In this context, we aimed to study the effects of maternal iodine status in the first and third trimesters of gestation on obstetric and neonatal outcomes in an iodine-sufficient population in Rio de Janeiro, Brazil. A total of 214 pregnant women in the first trimester of gestation were enrolled and prospectively followed until delivery between 2014 and 2017. All participants were ≥18 and ≤35 years, had a spontaneous single pregnancy, and had no history of thyroid or other chronic diseases, nor were they taking iodine-containing supplements at enrollment. In the first trimester, we obtained clinical information and determined thyroid function and the urinary iodine concentration (UIC) of the participants. Thyroid function and UIC were reassessed in the third trimester. Iodine status was determined by the median of UIC obtained from six urine spot samples by the inductively coupled plasma mass spectrometry method. Pregnancy and neonatal outcomes and delivery information were obtained from medical records. The median UIC in the whole population was 219.7 μg/L. The prevalence of UIC <150 μg/L was 17.2%, and 38.7% had UIC ≥250 μg/L. Gestational diabetes (GDM) was higher in the group with UIC 250-499 μg/L ( = 77) compared with the group with UIC 150-249 μg/L ( = 94) (20.3% vs. 9.7%, < 0.05). Ultimately, UIC ≥250 μg/L was an independent risk factors for GDM (relative risk [RR] = 2.9 [confidence interval, CI = 1.1-7.46], = 0.027) and hypertensive disorders of pregnancy (HDP) (RR = 4.6 [CI = 1.1-18.0], = 0.029). Among 196 live-born newborns, lower birth length was observed in infants whose mothers had UIC <150μg/L ( = 37) in the first trimester compared with those with UIC 150-249 μg/L ( = 86) (median interquartile range: 48.0 [2.2] vs. 49.0 [4.0] cm, = 0.01). Maternal UIC <150 μg/L was negatively associated with birth length of newborns (Exp (B) = 0.33 [CI = 0.1-0.9], = 0.03). In a population whose median iodine intake is sufficient, extensive individual variation occurs. Such abnormalities are associated with increased GDM and HDP when UIC is ≥250 μg/L, and lower infant birth length when UIC is <150 μg/L.
在妊娠期间碘摄入不足或过量可能会影响母体甲状腺功能的适应性机制，导致不良的妊娠结局。在这种情况下，我们旨在研究巴西里约热内卢碘充足人群中妊娠第一和第三孕期母体碘状况对产科和新生儿结局的影响。
共有 214 名处于妊娠第一孕期的孕妇入组并进行前瞻性随访，直至 2014 年至 2017 年期间分娩。所有参与者年龄均在 18 岁至 35 岁之间，自发性单胎妊娠，无甲状腺或其他慢性疾病史，入组时也未服用含碘补充剂。在第一孕期，我们获得了临床信息，并确定了参与者的甲状腺功能和尿碘浓度（UIC）。在第三孕期再次评估了甲状腺功能和 UIC。碘状况通过电感耦合等离子体质谱法测定的 6 个尿点样中 UIC 的中位数来确定。妊娠和新生儿结局以及分娩信息均从病历中获得。
在整个人群中，UIC 的中位数为 219.7μg/L。UIC<150μg/L 的患病率为 17.2%，38.7%的 UIC≥250μg/L。UIC 为 250-499μg/L（n=77）的组与 UIC 为 150-249μg/L（n=94）的组相比，妊娠期糖尿病（GDM）的发生率更高（20.3%比 9.7%， < 0.05）。最终，UIC≥250μg/L 是 GDM（相对风险 [RR] = 2.9 [95%置信区间，CI = 1.1-7.46]， = 0.027）和妊娠高血压疾病（HDP）（RR = 4.6 [95%CI = 1.1-18.0]， = 0.029）的独立危险因素。在 196 名活产新生儿中，与 UIC 为 150-249μg/L（n=86）的新生儿相比，UIC<150μg/L（n=37）的新生儿出生时的身长更短（中位数四分位距：48.0 [2.2] vs. 49.0 [4.0] cm， = 0.01）。母亲 UIC<150μg/L 与新生儿出生时的身长呈负相关（Exp（B）=0.33 [95%CI = 0.1-0.9]， = 0.03）。
在碘摄入量中位数充足的人群中，个体差异较大。当 UIC 为≥250μg/L 时，这种异常与 GDM 和 HDP 的增加有关，而当 UIC 为<150μg/L 时，与婴儿出生时的身长较低有关。
