A randomised, controlled trial of iodide supplementation in preterm infants

甲状腺素是一种由甲状腺产生的激素，对大脑的正常发育至关重要。低血清甲状腺素水平（低甲状腺素血症）常见于极早产儿（妊娠31周以下），这种低甲状腺素血症与神经发育受损有关。在英国，每年约有7500名极端早产儿出生;假设存活率为70%，估计残疾率为20%。碘是合成甲状腺素所必需的。极端早产儿最初仅通过胃肠外喂养（直接进入血流），然后逐渐引入肠内喂养（直接进入胃肠道），并在临床上适当增加。肠外营养液严重缺碘，婴儿在接受全肠外营养时处于负碘平衡。我们的研究旨在确定与未补充碘的婴儿相比，补充碘营养是否能使极早产儿达到正碘平衡，以及这是否能保护这组婴儿的大脑发育。本研究将从英国21个新生儿单位中招募妊娠24至31周的婴儿。婴儿将被随机分配接受每日碘补充剂或不接受碘补充剂，直至其相当于妊娠34周。试验期间将测量甲状腺激素水平，并收集产前和产后期间的疾病和事件数据。所有婴儿在两岁时的神经发育将使用已建立的发育测试进行评估。欲了解更多背景信息，请参见www.euthyroid.org

Thyroxine is a hormone produced by the thyroid gland and is essential for normal brain development. Low serum thyroxine levels (hypothyroxinaemia) are common in extreme preterm infants (under 31 weeks gestation) and this hypothyroxinaemia is associated with neurodevelopmental compromise. About 7500 extreme preterm infants are born per annum in the UK; with an estimated 20% disability rate, assuming 70% survival. Iodide is required for synthesis of thyroxine. Extreme preterm infants are initially exclusively parenterally fed (directly into the blood stream) and enteral feeds (directly into the gastro-intestinal tract) are gradually introduced and increased as clinically appropriate. Parenteral nutrition solutions are severely iodide deficient and infants are in negative iodide balance while on total parenteral nutrition. Our study aims to determine whether nutritional supplementation with iodide compared to non-supplemented infants enables extreme preterm infants to achieve a positive iodide balance and whether this protects brain development in this group of infants.This study will recruit infants born between 24 and 31 weeks gestation from a pool of 21 neonatal units in the UK. Infants will be randomised to receive a daily iodide supplement or not until they are the equivalent of 34 weeks gestation. Thyroid hormone levels will be measured during the trial and data will be collected about illnesses and events during the prenatal and postnatal periods. Neurodevelopment will be assessed in all infants at two years of age using established developmental tests.For further background information see www.euthyroid.org