Delayed gastric emptying increases the risk of pulmonary aspiration during anaesthesia for Caesarean delivery. Our aim in conducting this narrative review was to consider the effect of pregnancy on gastric emptying. The indices of gastric emptying after liquids, solids, or both and when fasted in the various trimesters of pregnancy, at the time of Caesarean delivery, in labour, and the postpartum period were assessed. We considered 32 observational studies, one nonrandomised controlled study, and 22 randomised controlled trials. The evidence indicates that, compared with the nonpregnant state, gastric emptying is decreased in the first but not the second and third trimesters. Before elective Caesarean delivery, carbohydrate drink or tea with milk leads to no difference in gastric cross-sectional area at 2 h relative to fasting or water. Following a standard fast for elective Caesarean delivery, patients may still have high-risk gastric contents. Compared with the nonpregnant state and third trimester, gastric emptying is delayed in labour, although the choice of analgesia has modifying effects. Systemic opioids delay gastric emptying. Epidural analgesia increases gastric emptying, but not back to baseline. Intrathecal analgesia delays gastric emptying relative to epidural analgesia. Women in labour who have eaten solids in the last 8 h still have high-risk gastric contents present in the stomach. The evidence with respect to the postpartum period is conflicting. In conclusion, inconsistencies in the literature reflect the unpredictability of gastric emptying in pregnancy and underline the potential value of gastric ultrasound in women who are pregnant.

中文翻译：

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妊娠期胃排空及其临床意义：叙述性回顾。


胃排空延迟会增加剖宫产麻醉期间肺误吸的风险。我们进行本叙述性综述的目的是考虑妊娠对胃排空的影响。评估了妊娠不同孕期、剖宫产时、分娩时和产后进食液体、固体或两者兼而有之后以及禁食后胃排空的指标。我们考虑了 32 项观察性研究、1 项非随机对照研究和 22 项随机对照试验。证据表明，与非妊娠状态相比，妊娠早期和晚期的胃排空减少，但孕中期和晚期的胃排空量没有减少。在选择性剖宫产前，碳水化合物饮料或茶加牛奶导致 2 小时时胃横截面积相对于空腹或水没有差异。在选择性剖宫产的标准禁食后，患者可能仍有高危胃内容物。与非妊娠状态和妊娠晚期相比，分娩时胃排空延迟，尽管镇痛的选择具有调节作用。全身性阿片类药物可延迟胃排空。硬膜外镇痛增加胃排空，但不回到基线。相对于硬膜外镇痛，鞘内镇痛延迟胃排空。在过去 8 小时内进食固体食物的分娩妇女的胃中仍存在高危胃内容物。关于产后时期的证据是相互矛盾的。总之，文献中的不一致反映了妊娠期胃排空的不可预测性，并强调了胃超声对孕妇的潜在价值。