Comparison of serial amnioinfusion strategies for isolated early-onset fetal renal anhydramnios.
Academic Article
Overview
abstract
Introduction The optimal protocol for serial amnioinfusions to maintain amniotic fluid in pregnancies with early onset-fetal renal anhydramnios before 22 weeks is not known. We compared the performance of two different approaches. Methods A secondary analysis was conducted of serial amnioinfusions performed by a single center during the external pilot and feasibility phases of the Renal Agenesis Fetal Therapy (RAFT) trial. During the external pilot, higher amnioinfusion volumes were given less frequently; in the feasibility study, smaller volume amnioinfusions were administered more frequently. Procedural details, complications, and obstetric outcomes were compared between the two groups using Pearson's chi-squared or Fisher's Exact tests for categorical variables and Student's t-tests or Wilcoxon Rank-Sum tests for continuous variables. The adjusted association between procedural details and chorioamniotic separation was obtained through a multivariate repeated measure logistic regression model. Results Eleven participants underwent 159 amnioinfusions (external pilot: three patients, 21 amnioinfusions; feasibility: eight patients, 138 amnioinfusions). External pilot participants had fewer amnioinfusions (7 vs. 19.5 in the feasibility group, p = 0.04), larger amnioinfusion volume (750 vs. 500 mL, p < 0.01), and longer interval between amnioinfusions (6 [4-7] vs. 4 [3-5] days, p < 0.01). In the external pilot, chorioamniotic separation was more common (28.6% vs. 5.8%, p < 0.01), preterm prelabor rupture of membranes (PPROM) occurred sooner after amnioinfusion initiation (28 ± 21.5 vs. 75.6 ± 24.1 days, p = 0.03), and duration of maintained amniotic fluid between first and last amnioinfusion was shorter (38 ± 17.3 vs. 71 ± 19 days, p=0.03), compared to the feasibility group. While delivery gestational age was similar (35.1 ± 1.7 vs. 33.8 ± 1.5 weeks, p=0.21), feasibility participants maintained amniotic fluid longer. Conclusion Small volume serial amnioinfusions performed more frequently maintain normal amniotic fluid volume longer because of delayed occurrence of PPROM.
