# Maternal and Neonatal Outcomes Following Ultrasound-Guided Microwave Ablation for Selective Fetal Reduction in Complicated Monochorionic Pregnancies: A Case Series

## TL;DR

This case series evaluates the outcomes of using microwave ablation for fetal reduction in complicated twin pregnancies, showing effectiveness with no maternal complications.

## Contribution

The study introduces microwave ablation as a new technique for selective fetal reduction in monochorionic pregnancies.

## Key findings

- Microwave ablation was successfully performed in all 21 cases with complete cessation of fetal blood circulation.
- The procedure had an 81% survival rate and no maternal complications, though 19% of fetuses were lost after the procedure.
- Babies had a 70.6% NICU admission rate, but all survived the neonatal period.

## Abstract

Microwave ablation (MWA) is a newly introduced technique for selective fetal reduction in complicated monochorionic (MC) pregnancies. This study aimed to describe maternal and neonatal outcomes after implementing MWA for selective fetal reduction in complicated MC pregnancies and analyze the procedure’s success rate.

This is a case series of 21 complicated MC pregnancies that underwent MWA in the Fetal-Maternal Center affiliated with Shiraz University of Medical Sciences (Shiraz, Iran) to occlude fetal blood circulation from May 2021 to May 2022. The participants were followed until delivery. Gestational age at the time of the procedure, duration of the procedure, survival rate, procedure-to-delivery time, gestational age at delivery, as well as maternal and neonatal outcomes were evaluated.

MWA was successfully performed in all 21 cases. The median (Q1-Q3) gestational age at the time of the procedure was 18 weeks. The fetus’s blood circulation was completely stopped in all cases.
The median (Q1-Q3) total ablation time was 4 (3-6) min, and the total ablation voltage was 100 (100-200) W. Fetal loss occurred in 19% (4/21) of cases after MWA. The duration of the surgery showed a significant negative correlation with the surgical outcome (P=0.012). The overall procedure-to-delivery time was 16 (14.5-19.5) weeks, with a survival rate of 81%. The median gestational age at delivery was 34 (30.5-37.5) weeks. Among the babies, 70.6% required admission to the neonatal intensive care unit; however, all survived the neonatal period. No maternal complications were observed.

MWA represents a potentially effective alternative modality for selective fetal reduction in complicated MC twin pregnancies. As a newly introduced technique, it is still in its early
stages of implementation, and there is a need for reporting and discussing the specific details of its application.

The abstract of this article was presented at the International Fetal Medicine Foundation Congress in the Emirates (28-29 September 2024).