The effects of maternal glucocorticoid administration in growth restricted fetuses.

对有早产风险的孕妇产前给予糖皮质激素已被证明可促进胎儿肺成熟。然而，糖皮质激素如倍他米松具有一系列潜在有害的非肺部效应，包括胎儿心血管功能的显著改变。这一点很重要，因为宫内生长受限（IUGR）胎儿在澳大利亚的妊娠中占很大比例，有早产的风险，因此很可能接受母亲的治疗。从人类观察和动物研究中，有充分的证据表明，IUGR胎儿表现出一系列心血管适应性，即使胎盘灌注减少，也能确保维持向重要器官的氧气输送。然而，在最近的临床和实验研究中，我们已经证明，对IUGR胎儿给予倍他米松会引起胎儿血流的变化，这可能对IUGR胎儿有害。具体来说，我们认为糖皮质激素可能会增加生长受限胎儿心血管和脑损伤的风险。这些发现的意义和调节这些变化的机制尚不清楚，但它们对未来的临床管理有明确的意义。该建议代表了初步实验研究的进一步发展，以检查betalone在绵羊IUGR胎儿中的作用，并考虑到未来的临床护理。

Antenatal administration of glucocorticoids to pregnant women at risk of preterm delivery has been shown to enhance fetal lung maturation. However, glucocorticoids such as betamethasone have a range of potentially deleterious non-pulmonary effects, which include significant alterations in fetal cardiovascular function. This is important because intrauterine growth restricted (IUGR) fetuses constitute a significant proportion of pregnancies in Australia, are at risk of preterm delivery and are therefore likely to receive maternal betamethasone. From both human observations and animal studies, it is well documented that IUGR fetuses demonstrate a range of cardiovascular adaptations that ensure maintenance of oxygen delivery to vital organs despite reduced placental perfusion. However, in recent clinical and experimental studies we have demonstrated that administration of betamethasone to IUGR fetuses induces changes in fetal blood flow that may be detrimental to the IUGR fetus. Specifically, we believe that glucocorticoids may increase the risk of both cardivascular and cerebral damage in the growth restricted fetus. The significance of these findings and the mechanisms regulating these changes remain unclear but they have clear implications for future clinical management. This proposal represents the further development of preliminary experimental studies to examine the effects of betamethasone in the ovine IUGR fetus with future clinical care in mind.