Drug entry into the adult brain is controlled by efflux mechanisms situated in various brain barrier interfaces. The effectiveness of these protective mechanisms in the embryo, fetus and newborn brain is less clear. The longstanding belief that “the” blood‐brain barrier is absent or immature in the fetus and newborn has led to many misleading statements with potential clinical implications. Here we review the properties of brain barrier mechanisms in the context of drug entry into the developing brain and discuss the limited number of studies published on the subject. We noticed that most of available literature suffers from some experimental limitations, notably that drug levels in fetal blood and cerebrospinal fluid have not been measured. This means that the relative contribution to the overall brain protection provided by individual barriers such as the placenta (which contains similar efflux mechanisms) and the brain barriers cannot be separately ascertained. Finally, we propose that systematic studies in appropriate animal models of drug entry into the brain at different stages of development would provide a rational basis for use of medications in pregnancy and in newborns, especially prematurely born, where protection usually provided by the placenta is no longer present.

中文翻译：

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孕妇用药：母亲和胎儿利益之间的平衡行为。

进入成人大脑的药物由位于各种脑屏障界面的外排机制控制。这些保护机制在胚胎、胎儿和新生儿大脑中的有效性尚不清楚。长期以来认为胎儿和新生儿“血脑屏障”不存在或不成熟的信念导致了许多具有潜在临床意义的误导性陈述。在这里，我们回顾了在药物进入发育中的大脑的背景下脑屏障机制的特性，并讨论了关于该主题的有限数量的研究。我们注意到，大多数可用文献都存在一些实验限制，特别是尚未测量胎儿血液和脑脊液中的药物水平。这意味着无法分别确定胎盘（包含类似的外排机制）和脑屏障等个体屏障对整体大脑保护的相对贡献。最后，我们建议在不同发育阶段药物进入大脑的适当动物模型中进行系统研究，将为妊娠和新生儿，尤其是早产儿使用药物提供合理的基础，胎盘通常无法提供保护。更长的存在。