Preliminary experience with microwave ablation for selective feticide in monochorionic twin pregnancies

Clinical value of high-intensity focused ultrasound in fetal reduction

Complex twin reduction surgery is a common but challenging procedure that aims to reduce the risks and complications of multiple pregnancies. The search for safer and more effective methods has led to the development of high-intensity focused ultrasound (HIFU) technology in the field of fetal reduction. This technology utilizes high-energy sound waves to focus precisely on specific areas, achieving non-invasive therapeutic effects. This paper discusses the principles and features of HIFU technology, as well as its application in complex twin reduction surgery. The paper aims to elucidate the important role of this technology in improving surgical outcomes and reducing risks, explore the current limitations of the modality, and propose directions for future development. Through these investigations, it is hoped to improve overall understanding of HIFU, and thereby promote the application of this technology in the field of fetal reduction.

Perinatal and neurodevelopmental outcome in complicated monochorionic pregnancy after selective fetal reduction: radiofrequency ablation vs microwave ablation

OBJECTIVES

To summarize our experience in the application of radiofrequency ablation (RFA) and microwave ablation (MWA) for selective fetal reduction in complicated monochorionic pregnancies and compare the perinatal outcome of the two techniques.

METHODS

This was a retrospective study of data from a consecutive cohort of all monochorionic twin pregnancies that underwent selective fetal reduction with RFA or MWA at Peking University Third Hospital, Beijing, China from January 2012 to December 2018. All surviving cotwins were followed up to assess their neurodevelopment using the Age & Stage Questionnaire, Chinese version. Perinatal and neurodevelopmental outcomes were compared between the RFA and MWA groups. We also fitted multivariable models to test the association between procedure-related factors and the main perinatal outcomes, including preterm birth (PTB) < 37 weeks' gestation, intrauterine fetal death (IUFD) of the cotwin, adverse outcome (defined as occurrence of IUFD of the cotwin, termination of pregnancy or PTB < 28 weeks) and overall survival.

RESULTS

In total, 45 cases (42 twin and three triplet pregnancies) underwent RFA and 126 cases (105 twin and 21 triplet pregnancies) underwent MWA. The overall survival rates in monochorionic diamniotic twin pregnancies were similar between the RFA and MWA groups (61.0% vs 67.0%; P = 0.494). However, pregnancies whose indication for fetal reduction was selective intrauterine growth restriction or twin reversed arterial perfusion had higher overall survival rates (75.5% and 82.6%, respectively) compared with those in other indication groups. A total of 104 children were followed up (20 in the RFA group and 84 in the MWA group); four (20.0%) and eight (9.5%) children were assessed as having overall developmental delay in the RFA and MWA groups, respectively, with no significant difference between the two groups. Multivariable analyses showed that procedure indication, number of ablation cycles and gestational age at procedure were associated significantly with the main perinatal outcomes.

CONCLUSIONS

RFA and MWA for selective fetal reduction in complicated monochorionic pregnancies can achieve similar overall survival rate and neurodevelopmental outcome, but MWA is associated with a lower risk of preterm birth. Moreover, procedure-related factors are associated significantly with perinatal outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Care Levels for Fetal Therapy Centers

Fetal therapies undertaken to improve fetal outcome or to optimize transition to neonate life often entail some level of maternal, fetal, or neonatal risk. A fetal therapy center needs access to resources to carry out such therapies and to manage maternal, fetal, and neonatal complications that might arise, either related to the therapy per se or as part of the underlying fetal or maternal condition. Accordingly, a fetal therapy center requires a dedicated operational infrastructure and necessary resources to allow for appropriate oversight and monitoring of clinical performance and to facilitate multidisciplinary collaboration between the relevant specialties. Three care levels for fetal therapy centers are proposed to match the anticipated care complexity, with appropriate resources to achieve an optimal outcome at an institutional and regional level. A level I fetal therapy center should be capable of offering fetal interventions that may be associated with obstetric risks of preterm birth or membrane rupture but that would be very unlikely to require maternal medical subspecialty or intensive care, with neonatal risks not exceeding those of moderate prematurity. A level II center should have the incremental capacity to provide maternal intensive care and to manage extreme neonatal prematurity. A level III therapy center should offer the full range of fetal interventions (including open fetal surgery) and be able manage any of the associated maternal complications and comorbidities, as well as have access to neonatal and pediatric surgical intervention including indicated surgery for neonates with congenital anomalies.

Perinatal outcomes after selective feticide via umbilical cord occlusion in complicated monochorionic pregnancies: A systematic review and meta-analysis

OBJECTIVE

We aimed to compare perinatal outcomes between umbilical cord occlusion techniques in monochorionic pregnancies, including umbilical cord ligation, fetoscopic laser coagulation, interstitial laser coagulation, bipolar cord occlusion, radiofrequency ablation, and microwave ablation.

METHODS

This study was registered with PROSPERO (CRD42020158861). PubMed, Web of Science, Cochrane Library, and Embase were searched for studies published up to May 2020. The DerSimonian-Laird random-effects model was used for the meta-analysis. Subgroup analyses were performed to compare the outcomes among the six techniques. Meta-regression was used to adjust for confounders.

RESULTS

Thirty-four studies with 1646 participants were included. The overall survival was 76.5% after umbilical cord ligation, 78.8% after fetoscopic laser coagulation, 60.3% after interstitial laser coagulation, 79.2% after bipolar cord occlusion, 77.5% after radiofrequency ablation, and 75.0% after microwave ablation. Subgroup comparison showed the rates of overall survival and preterm premature rupture of membranes were not significant different among six techniques. However, rates of fetal loss, premature birth, live birth, and neonatal death differed significantly among the six groups.

CONCLUSIONS

The choice of umbilical cord occlusion techniques will affect perinatal outcomes. We suggested that the choice of umbilical cord occlusion techniques should fully consider these differences among techniques.

Microwave ablation versus radiofrequency ablation for the treatment of severe complicated monochorionic pregnancies in China：protocol for a pilot randomised controlled trial

INTRODUCTION

Complicated monochorionic twin pregnancies are often associated with high perinatal morbidity and mortality, some of which are severe enough to require a gestational reduction surgery to improve fetal survival and reduce disabilities. While radiofrequency ablation is currently the most commonly used procedure with higher fetal survival and fewer maternal and fetal complications compared with other surgical methods, the therapeutic effect of microwave ablation (MWA) is reported to be better, presumably due to the higher thermal effect and fewer restrictions. Currently there is limited evidence to prove the feasibility of MWA for selective reduction. The aim of this pilot study is to explore the feasibility, efficacy and safety of MWA reduction for severe complicated monochorionic pregnancies and may provide evidence for using the MWA in intrauterine surgeries extensively.

METHODS AND ANALYSIS

This is a study protocol for a parallel-design pilot randomised controlled trial. 60 eligible patients with severe complicated monochorionic pregnancies will be randomised in a ratio of 1:1 to MWA group and radiofrequency group. Patients will be followed up until 6 months of age of the retained fetal. The primary analysis will compare the rates of neonatal survival at 28 days to evaluate the effect of MWA. The study will also evaluate the safety profile of MWA including the occurrence of postoperative adverse events and maternal and fetal complications. Additional secondary outcomes to be explored include the condition of neonatal asphyxia and the growth of surviving fetus at 6 months. Outcomes will be analysed by both a frequentist and the Bayesian statistical approach.

ETHICS AND DISSEMINATION

This study was approved by the ethical review committee of the Peking University Third Hospital (Beijing, China). The results of this study will be published in peer-reviewed scientific journals and presented at relevant academic conferences.

TRIAL REGISTRATION NUMBER

NCT04014452; Pre-results.

Reduction of multiple pregnancy: Counselling and techniques

The incidence of multiple births has risen in the last few decades. This rise is mainly due to the widespread use of assisted reproduction techniques mainly as a result of increasing maternal age at conception. Twin and higher-order multiple pregnancies are associated with increased risk of perinatal, as well as maternal, mortality and morbidity compared to singleton pregnancies. There can also be psychosocial and socioeconomic implications for women and their families. In this chapter, we aim to discuss the risks associated with multiple pregnancies, the pros and cons of fetal reduction, the current techniques used in clinical practice, and how to approach counselling parents, enabling them to make informed decisions.

Successful Transvaginal Microwave Ablation of a Heterotopic Cervical Pregnancy. A Case Report

Heterotopic cervical pregnancy is a rare and potentially dangerous condition where the challenge is the removal of the ectopic pregnancy while preserving the intrauterine one. We present the case of an otherwise healthy 36-year-old woman with heterotopic cervical pregnancy after an IVF cycle for tubal infertility. At 6.5 weeks after a consultation with gynecologists and interventional radiologists, the patient agreed to undergo microwave ablation of the cervical pregnancy. Monthly ultrasound examination showed the persistence of non homogeneous and vascularized tissue in the cervix. Intrauterine pregnancy continued without complications until 37 weeks when a cesarean section was performed for sudden and profuse bleeding, in the presence of uterine contractions. A healthy baby girl was delivered, and the postoperative course was otherwise uncomplicated. Heterotopic cervical pregnancies are rare, and no consolidated and risk-free treatments are available at the moment. Here, we present a case of heterotopic cervical pregnancy treated successfully and without complications with microwave ablation.

Successful management of diaphragmatic ectopic pregnancy using ultrasound-guided percutaneous microwave ablation

Diaphragmatic ectopic pregnancy is a rare status during the perinatal period. We reported that a 24-year-old woman with diaphragmatic ectopic pregnancy successfully received ultrasound-guided percutaneous microwave ablation. It found that beta-human chorionic gonadotropin level decreased showing 1067, 311.3 and 118.4 mIU/mL within five postoperative days, and P level reduced from 3.64 to 1.59 nmol/L. Contrast-enhanced ultrasonography image on the third day after ablation indicated that there was no enhancement in the lesion. This case indicated that ultrasound-guided percutaneous microwave ablation could be critical for a good outcome in diaphragmatic ectopic pregnancy.

Forty-five consecutive cases of complicated monochorionic multiple pregnancy treated with microwave ablation: A single-center experience

OBJECTIVE

To describe our preliminary experience in the application of microwave ablation for selective fetal reduction in complicated monochorionic multiple pregnancies.

METHODS

In this prospective study, 45 consecutive complicated monochorionic multiple pregnancies that underwent microwave ablation for selective fetal reduction from July 2015 to February 2017 were analyzed from the first case onward. All patients were managed at the Peking University Third Hospital in Beijing, China.

RESULTS

There were 45 cases (twins in 40 and triplets in five) treated by microwave ablation. The median gestational age at surgery was 21.3 weeks (range, 15.9-25.7 wk), with a mean total ablation time of 8.5 ± 4.2 (7.2-9.7) minutes. There were 12 (26.7%) cases of postprocedural fetal loss. Thirty-three women delivered alive at a median gestational age of 37.6 weeks (range, 28.6-40.4 wk). There were no neonatal deaths in our cohort, and the overall survival rate was 73.3% (33/45). Preterm premature rupture of membranes occurred in 9 (20.0%) cases with a median of 7.0 weeks (range, 0.9-16.3 wk) after the surgery. None of the surviving cotwins had evidence of thermal injury or neurological abnormalities.

CONCLUSION

Microwave ablation appears to be a safe and effective method for selective feticide in complicated monochorionic pregnancies.