Microwave ablation for selective feticide in complicated monochorionic twin pregnancies

Objective To evaluate the feasibility, safety and short-term fetal outcome of ultrasound-guided percutaneous microwave ablation for selective feticide in complicated monochorionic twin pregnancies. Methods Twenty-two patients who underwent microwave ablation for selective fetal reduction in Peking University Third Hospital between July 2015 and June 2016 were retrospectively studied. Surgical complications, fetal outcomes and neural development at age of 60 days were recorded. One-way ANOVA, Mann-Whitney U test, Chi-square or Fisher's exact test was used for statistical analysis. Results Indications of the 22 patients for selective feticide included five cases of twin pregnancy with one anomalous fetus, five cases of severe twin-twin transfusion syndrome (TTTS), three cases of twin reserved arterial perfusion (TRAP) and nine cases of selective intrauterine growth restriction (sIUGR). All surgeries were successful under regional anesthesia. Four pregnancies (18.2%, 4/22) ended in miscarriage following surgery, three of which were caused by intrauterine fetal death (13.6%, 3/22) and one by premature rupture of membranes before 26 weeks of gestation (4.5%, 1/22). Totally, 18 babies were born alive at an average gestational age of (35.5±4.2) weeks (26~40 weeks+2) and with an average birth weight of (2 380±778) g (800~3 430 g), and four of them were preterm infants less than 32 weeks of gestation. Except for one extremely low birth weight infant, whose gestational age was 26 weeks at birth and birth weight was 800 g, died two days after birth, 17 infants were discharged alive, giving an neonatal survival rate of 17/18. The total fetal survival rate was 77.3% (17/22). Polyhydramnios, placenta location, and position of the fetus being aborted showed no significant effect on miscarriage or fetal survival rate (all P>0.05). No severe maternal complications occurred. No brain injuries were detected by imaging examination in 17 infants who were followed up to 60 days of age. Conclusions Ultrasound-guided percutaneous microwave ablation can be used for selective feticide in complicated monochorionic twin pregnancies. Further studies are needed to evaluate its effects on long-term fetal outcome. Key words: Pregnancy reduction, multifetal; Pregnancy, twin; Surgical procedures, elective; Ablation techniques; Microwaves