is an active area of research for patients. In review articles, the evidence shows that there is likely a prolongation of gestation and decreased perinatal mortality, neonatal sepsis, and pulmonary hypoplasia. Contraindications Relative contraindications for amnioinfusion include intrauterine infection and maternal immunosuppression to avoid systemic infection, placental abruption and evidence of fetal distress on fetal heart rate monitoring as these are more emergent conditions requiring surgery, and uterine contractions because these make it technically difficult to perform transabdominal amnioinfusion. Complications Amnioinfusion can be complicated by premature rupture of membranes, intrauterine infection, maternal pulmonary embolus, puncture and hemorrhage of umbilical cord, precipitous labor, and placental abruption. There are minimal literature addressing incidence rates of these various complications. There are also case reports showing concern for amniotic fluid embolus, polyhydramnios, and malpresentation. It is recommended that amnioinfusion be performed at centers specializing in fetal medicine and within the context of a multidisciplinary team. Technique The most common method of amnioinfusion is the transabdominal approach. The abdomen is generally numbed with local anesthesia and a small needle is inserted into the abdomen, through the uterus, and into the intrauterine cavity. This is performed under ultrasound guidance, often with doppler, to avoid injuring the fetus, placenta, or umbilical cord and aspiration is performed at the time to ensure intra-uterine placement. Warm normal saline is generally used to then increase the amniotic fluid index to over 5 cm. Amnioinfusion can also be performed transcervically (through the cervix) after the amniotic sac has ruptured. History Amnioinfusion was initially performed as a means of achieving first- and second-trimester abortion through the infusion of formalin and hypertonic glucose. Hypertonic saline was first used in the 1960s in the United States to induce labor in patients whose pregnancy ended in intrauterine death. In the 1970s, hypertonic saline overtook other solutions for performing abortions before 14 weeks of gestation. Due to its high risk for infection, hemorrhage, and retained placental tissue leading to a roughly 10% mortality rate, amnioinfusion was largely replaced by prostaglandin medications for performing abortions in the 1980s. It was at this time that medical providers began to use amnioinfusion for other therapeutic purposes. The first report of using isotonic saline or Lactated Ringers solution for repeated late decelerations on fetal heart tracing was in 1983 using either a spinal needle or transcervical catheter. In the following decade, medical providers found more applications, including preventing meconium aspiration