Bynarowicz Taylor, Jenkins Suzanne M., Shanks Anthony L.
University of South Carolina School of Medicine Greenville
Oligohydramnios is defined as decreased amniotic fluid volume (AFV) for gestational age and is associated with increased rates of neonatal morbidity. AFV is typically assessed via transabdominal ultrasound using either the amniotic fluid index (AFI) or the single deepest vertical pocket (DVP) techniques. Oligohydramnios is defined as an AFI ≤5 cm or DVP, also referred to as the maximum vertical pocket (MVP) or single deepest pocket (SDP), <2 cm. Oligohydramnios develops when the mechanisms that regulate AFV are disrupted. Most often, this is due to reduced fetal urination, uteroplacental insufficiency, or loss of amniotic fluid with membrane rupture. However, in many cases, an etiology is never identified. As oligohydramnios is a symptomatic reflection of an underlying etiology, patients should be evaluated to identify the abnormal condition resulting in low AFV. Oligohydramnios assessment comprises a targeted history and physical examination, detailed ultrasound imaging, and amniocentesis for genetic testing if fetal anomalies or history-based risk factors are identified. The management and prognosis of oligohydramnios primarily depend on the underlying pathophysiology and the gestational age at diagnosis. Increased antepartum surveillance and early delivery are typically indicated in patients with idiopathic disease.
羊水过少定义为妊娠期间羊水体积（AFV）减少，且与新生儿发病率升高相关。AFV通常通过经腹超声检查，采用羊水指数（AFI）或单一最深垂直羊水池（DVP）技术进行评估。羊水过少定义为AFI≤5cm或DVP（也称为最大垂直羊水池（MVP）或单一最深羊水池（SDP））<2cm。当调节AFV的机制受到破坏时，就会发生羊水过少。最常见的原因是胎儿排尿减少、子宫胎盘功能不全或胎膜破裂导致羊水流失。然而，在许多情况下，病因始终无法确定。由于羊水过少是潜在病因的症状表现，应对患者进行评估，以确定导致AFV降低的异常情况。羊水过少的评估包括有针对性的病史和体格检查、详细的超声成像检查，以及如果发现胎儿异常或基于病史的风险因素，则进行羊膜腔穿刺术以进行基因检测。羊水过少的处理和预后主要取决于潜在的病理生理学以及诊断时的孕周。对于特发性疾病患者，通常需要加强产前监测并尽早分娩。
