Changes in the Intra-Amniotic Pressure following Transabdominal Amnioinfusion during Pregnancy

OBJECTIVE: The aim of the article was to investigate the changes in intra-amniotic pressure following transabdominal amnioinfusion during pregnancy. DESIGN: This retrospective study included 19 pregnant women who underwent transabdominal amnioinfusion during pregnancy to relieve umbilical cord compression and improve the intrauterine environment or to increase the accuracy of ultrasonography. MATERIALS AND METHODS: We measured and analyzed the changes in intra-amniotic pressure, single deepest pocket, and the amniotic fluid index before and after amnioinfusion. We also determined the incidence of maternal or fetal adverse events, such as preterm premature rupture of membranes, preterm delivery, fetal death within 48 h, placental abruption, infection, hemorrhage, and peripheral organ injury. RESULTS: A total of 41 amnioinfusion procedures were performed for 19 patients. The median gestational age during the procedure was 24.3 weeks. The median volume of the injected amniotic fluid was 250 mL. The median single deepest pocket and amniotic fluid index after amnioinfusion were significantly higher than those before amnioinfusion (4.0 cm vs. 2.65 cm; p < 0.001 and 13.4 cm vs. 6.0 cm; p < 0.001). However, the median (range) intra-amniotic pressure after amnioinfusion was not significantly different compared to that before amnioinfusion (11 mm Hg vs. 11 mm Hg; p = 0.134). Maternal or fetal adverse events were not observed following amnioinfusion. CONCLUSION: Intra-amniotic pressure remained unchanged following amnioinfusion. The complications associated with increased intra-amniotic pressure are not likely to develop if the amniotic fluid index and/or single deepest pocket remains within the normal range after amnioinfusion. Studies of groups with and without complications are warranted to clarify the relationship between the intra-amniotic pressure and incidence of complications.