Amnioreduction safety in singleton pregnancies; systematic review and meta-analysis

Prenatal ultrasound identifies polyhydramnios in approximately 0.7 % of pregnancies. Polyhydramnios (defined as amniotic fluid index >24 cm) is associated with maternal symptoms and preterm delivery. However, amnioreduction (AR) can effectively alleviate symptoms and reduce preterm delivery risks; its advantages remain controversial. This study aims to assess maternal safety following AR in singleton pregnancies systematically.

Databases searched included PubMed, Embase, Scopus, and Web of Science until April 2024. Pregnant patients with singleton pregnancy and polyhydramnios undergo AR included in our study. Statistical analyses were conducted using R software.

From 574 initially identified articles, seven studies with 390 singleton pregnancies who underwent AR were included. The primary outcomes showed low odds of placental abruption 0.04 (95 % CI: 0.02-0.09, I²=12 %) and chorioamnionitis 0.03 (95 % CI: 0.01-0.08, I²=0 %). Secondary outcomes indicated a mean gestational age at birth of almost 36 weeks (95 % CI: 35.51-36.41, I²=49 %) and low odds of cesarean delivery 0.45 (95 % CI: 0.30-0.61, I2=58 %), preterm delivery within 48 h after AR 0.10 (95 % CI: 0.07-0.15, I²=9 %) and PPROM within 48 h after AR 0.03 (95 % CI: 0.02-0.04, I²=0 %).

This study demonstrates that maternal complications are expected to be low following the AR procedure. However, given the lack of evidence for fetal benefit and pregnancy prolongation, future studies should directly compare the effects of AR with expectant management. Additionally, fetal survival is likely influenced more by the underlying fetal diagnosis or the etiology of polyhydramnios rather than AR itself. The current meta-analyses will serve as a guide for shared decision-making, and highlight the need for continued clinical trials powered to establish superiority or benefit with AR for singleton pregnancies.