Despite improvements in clinical management, pregnancies complicated by pre-existing diabetes mellitus, gestational diabetes mellitus or obesity carry substantial risks for parent and offspring. Some of the endocrine and metabolic changes in parent and fetus in diabetes mellitus and obesity lead to fetal oxygen deficit, mostly due to insulin-induced accelerated fetal metabolism. The human fetus deals with reduced oxygenation through a wide range of adaptive responses that act at various levels in the placenta as well as the fetus. These responses ensure adequate oxygen delivery to the fetus, increase the oxygen transport capacity of fetal blood and redistribute oxygen-rich blood to vital organs such as the brain and heart. The liver has a central role in adapting to reduced oxygenation by increasing its oxygen extraction and stimulating erythropoietin synthesis to increase haematocrit. The type of adaptive response depends on the onset and duration of hypoxia and the severity of the metabolic disturbance. In pregnancies characterized by diabetes mellitus or obesity, these adaptive systems come under additional strain owing to the increased maternal supply of glucose and resultant fetal hyperinsulinaemia, both of which stimulate oxidative metabolism. In the rare situation that the adaptive responses are overwhelmed, stillbirth can ensue.

尽管临床管理有所改善，但因既往糖尿病、妊娠糖尿病或肥胖而并发的妊娠会给父母和后代带来巨大风险。糖尿病和肥胖症中父母和胎儿的一些内分泌和代谢变化导致胎儿缺氧，主要是由于胰岛素诱导的胎儿代谢加速。人类胎儿通过在胎盘和胎儿的不同水平上起作用的广泛的适应性反应来处理氧合减少。这些反应确保向胎儿提供足够的氧气，增加胎儿血液的氧气运输能力，并将富含氧气的血液重新分配到大脑和心脏等重要器官。肝脏通过增加其氧提取和刺激促红细胞生成素合成以增加血细胞比容，在适应氧合减少方面具有核心作用。适应性反应的类型取决于缺氧的发生和持续时间以及代谢紊乱的严重程度。在以糖尿病或肥胖为特征的妊娠中，由于母体葡萄糖供应增加和由此产生的胎儿高胰岛素血症，这些适应性系统受到额外的压力，这两者都会刺激氧化代谢。在适应性反应不堪重负的罕见情况下，可能会出现死产。由于母体葡萄糖供应增加和由此产生的胎儿高胰岛素血症，这些适应性系统承受了额外的压力，这两者都会刺激氧化代谢。在适应性反应不堪重负的罕见情况下，可能会出现死产。由于母体葡萄糖供应增加和由此产生的胎儿高胰岛素血症，这些适应性系统承受了额外的压力，这两者都会刺激氧化代谢。在适应性反应不堪重负的罕见情况下，可能会出现死产。