Selective reduction in complicated monochorionic pregnancies: a systematic review and meta-analysis of different techniques

Perinatal Outcomes Following Selective Fetal Terminations of Complicated Monochorionic Pregnancies: Experience From a Referral Center in Southern Spain

The objective of this study was to to describe perinatal outcomes in monochorionic twin pregnancies after selective fetal reduction using bipolar cord coagulation (BCC) or interstitial laser ablation (ILA). This retrospective cohort study included monochorionic twin pregnancies requiring selective fetal reduction between 2008 and 2023 at a referral center in Spain. Maternal and perinatal data were collected and analyzed to compare outcomes between BCC and ILA techniques. The primary outcome was the survival of the co-twin, while secondary outcomes included gestational age at delivery, the incidence of PPROM, birth weight and long-term neurodevelopmental outcomes. Eighty-four procedures were performed (30 ILA, 54 BCC). The overall co-twin survival rate was 80%, with BCC showing a higher survival rate (87%) compared to ILA (67%, p = .026). Fetal death before 24 weeks was more common in ILA (30%) than BCC (7.4%, p = .010). The mean gestational age at delivery was lower in BCC (36.6 weeks) than ILA (38.6 weeks, p = .021), and preterm delivery was more frequent in BCC (50%) compared to ILA (14%, p = .005). BCC seems to have a better overall survival than ILA in complicated monochorionic twins' selective terminations. However, we could not clarify whether this difference was due to the technique itself or the different gestational age at the time of the procedure as well as the specific indication.

A novel technique with cool-tip radiofrequency ablation for selective fetal reduction in complicated monochorionic twin

OBJECTIVE

To invent a novel method for selective fetal reduction in monochorionic (MC) twin using cool-tip radiofrequency ablation (RFA) and analysis the perinatal outcome.

MATERIAL AND METHODS

Complicated MC twins including twin-to twin transfusion syndrome (TTTS), selective fetal growth restriction (sFGR) and twin reverse arterial perfusion sequence (TRAP) were enrolled from 2020 to 2024. All cases were indicated for selective fetal reduction due to expected poor outcome. Equilateral triangle method using single puncture 4 times ablation with 17G cool-tip RFA to cord insertion site, umbilical vein and two umbilical arteries for complete stopping the blood flow. The power was starting from 60 W, 80 W, 80 W and 100 W 1 min each site. Outcome were analyzed.

RESULTS

A total of 51 cases were collected and treated in a single medical center. We divided first 20 cases as tradition group using single point ablation and novel 4-point ablation group after 21st cases. The overall co-twin survival rate after RFA procedure was 88 % (45 out of 51) in whole series. However, the co-twin survival rate in the novel 4-point group was better than single point group (93.5 % vs 80 %) with statistically significance. The maternal age, procedure at gestational age, procedure time and preterm birth rate did not show statistically difference between two groups.

CONCLUSIONS

This novel equilateral triangle method to stop all the umbilical blood flow achieved the high successful rate without maternal complication. The 17 g cool-tip RFA worked at low temperature to avoid thermal damage. This might be the new choice of RFA in monochorionic pregnancies.

Learning curve for the perinatal outcomes of radiofrequency ablation for selective fetal reduction: a single-center, 10-year experience from 2013 to 2023

OBJECTIVES

To investigate the perinatal outcomes of SR using radiofrequency ablation (RFA) in MC pregnancies, identified factors affecting these outcomes, and assessed the associated learning curve.

METHODS

This retrospective cohort study included all consecutive MC pregnancies that required RFA from September 2013 to April 2023 at our institution. The perinatal outcomes were compared on the basis of various indications, and binary logistic regression analysis was performed to identify the risk factors for cotwin loss. Clinical datas of two periods (2013-2018 vs. 2019-2023) were compared to demonstrate the learning curve.

RESULTS

The 107 cases composed of 40 (37.4 %) twin-twin transfusion syndrome (TTTS), 17 (15.9 %) selective intrauterine growth restriction (sFGR), 12 (11.2 %) twin reversed arterial perfusion sequence (TRAPS), 25 (23.4 %) fetal discordant anomalies, 10 (9.3 %) elective fetal reduction (EFR), and three (2.8 %) twin anemia polycythemia sequence (TAPS) cases. The overall live birth rate for cotwins was 83.2 %. The earliest gestational age at delivery was noted in the TTTS group (p=0.021). The procedure-to-delivery interval was the shortest in the TTTS group and the longest in the EFR group (p<0.001). Comparing the 2013-2018 period with the 2019-2023 period, we noted a significant increase in the live birth rate (p=0.01) and the procedure-to-delivery interval (p=0.003), mainly due to improved outcomes in TTTS cases.

CONCLUSIONS

RFA for SR is a safe and effective method for managing complicated MC pregnancies. The type of indication affects postoperative perinatal outcomes, with TTTS showing the most adverse effects. With the increasing number of cases and accumulation of experiences with simultaneous enhancement of technique proficiency, the postprocedural outcomes can be further improved.

Short- and Long-Term Outcome of Selective Reduction by Fetoscopy-Guided Bipolar Cord Coagulation in Monochronic Twin Pregnancies

INTRODUCTION

The aim of this study was to assess the short- and long-term outcome of selective reduction by fetoscopy-guided bipolar cord coagulation in monochronic twin pregnancies.

METHODS

Retrospective analysis was conducted of a consecutive cohort of all monochorionic twin pregnancies treated with fetoscopy-guided bipolar cord coagulation between December 2015 and December 2022 in a single center in China.

RESULTS

A total of 43 monochronic twin pregnancies undergoing fetoscopy-guided bipolar cord coagulation were analyzed. There were 5 intrauterine deaths with an 88.4% (38/43) survival rate overall. The preterm premature rupture of the membranes rate was 13.2%, and the preterm birth before 37 and 32 weeks was 42.1% and 13.1%, respectively. An uptrend in the survival rate (78.9 vs. 95.8%, p = 0.086) and a downtrend of procedure time (30 vs. 16.5 min, p = 0.036) were observed over time (period 1 from December 2015 to December 2019 verses period 2 from January 2020 to December 2022). Long-term outcome was assessed in 94.6% (35/37) of survivors, and 91.4% (32/35) had normal neurodevelopmental outcome.

CONCLUSION

Fetoscopy-guided bipolar cord coagulation for fetal reduction in complicated monochorionic twin pregnancies could achieve a favorable short- and long-term outcome, especially in experienced hands.

New radiofrequency ablation procedure for selective reduction in complicated monochorionic twin or triplet pregnancy using multistep, incremental expansion technique

OBJECTIVE

Radiofrequency ablation (RFA) is the preferred approach for selective reduction in complex monochorionic (MC) multiple pregnancies owing to the ease of operation and minimal invasiveness. To optimize the RFA technique and reduce the risk of adverse pregnancy outcome resulting from the heat-sink effect of RFA therapy, we used an innovative RFA method, in which an electrode needle was expanded incrementally and stepwise. This study aimed to assess the efficacy and safety profile of this novel multistep incremental expansion RFA method for selective fetal reduction in MC twin and triplet pregnancies.

METHODS

This was a single-center retrospective cohort study of all MC multiple pregnancies undergoing RFA between March 2016 and October 2022 at our center. The multistep RFA technique involved the use of an expandable needle, which was gradually expanded during the RFA procedure until cessation of umbilical cord blood flow was achieved. The needle used for the single-step RFA method was fully extended from the start of treatment.

RESULTS

In total, 132 MC multiple pregnancies underwent selective reduction using RFA, including 50 cases undergoing multistep RFA and 82 cases undergoing single-step RFA. The overall survival rates were not significantly different between the multistep and single-step RFA groups (81.1% vs 72.3%; P = 0.234). Similarly, the rates of preterm prelabor rupture of the membranes within 2 weeks after RFA, procedure-related complications, spontaneous preterm delivery and pathological findings on cranial ultrasound, as well as gestational age at delivery and birth weight, did not differ between the two groups. However, there was a trend towards a prolonged procedure-to-delivery interval following multistep RFA compared with single-step RFA (median, 109 vs 99 days; P = 0.377). Moreover, the fetal loss rate within 2 weeks after RFA in the multistep RFA group was significantly lower than that in the single-step RFA group (10.0% vs 24.4%; P = 0.041). The median ablation time was shorter (5.3 vs 7.8 min; P < 0.001) and the median ablation energy was lower (10.2 vs 18.0 kJ; P < 0.001) in multistep compared with single-step RFA. There were no significant differences in neonatal outcomes following multistep vs single-step RFA.

CONCLUSIONS

Overall survival rates were similar between the two RFA methods. However, the multistep RFA technique was associated with a lower risk of fetal loss within 2 weeks after RFA. The multistep RFA technique required significantly less ablation energy and a shorter ablation time compared with single-step RFA in selective fetal reduction of MC twin and triplet pregnancies. Additionally, there was a trend towards a prolonged procedure-to-delivery interval with the multistep RFA technique. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

Managing Monoamniotic Twin Pregnancies

Monoamniotic twins comprise a rare subset of twins at risk of unique and serious complications. In addition to the risks faced by all twins (premature birth, growth restriction), all monochorionic twins (twin-to-twin transfusion syndrome), and all monozygotic twins (congenital anomalies), monoamniotic twins face the unique risk of cord entanglement, in addition to a markedly increased risk of congenital anomalies. Early diagnosis, screening for fetal anomalies and surveillance for twin-twin transfusion syndrome are critical. After fetal viability, frequent fetal monitoring reduces the risk of intrauterine fetal demise.

Twin reverse arterial perfusion: Timing of intervention

Twin reverse arterial perfusion (TRAP) sequence is a severe anomaly in monochorionic twins where one twin has profound corporeal underdevelopment and acardia. The normal "pump" co-twin provides blood flow to the acardiac twin through placental anastomoses which may lead to cardiac failure and pump twin demise as well as preterm delivery from severe polyhydramnios. Treatments include radiofrequency ablation, bipolar cord coagulation, and intrafetal laser with each aimed at occluding blood flow to the acardiac twin. However, none of these modalities has proven superior in terms of either pump twin survival or minimization of complications, including preterm premature rupture of membranes, preterm birth, or unexpected co-twin demise. The optimal timing of treatment is also unknown, without clear indications for intervention versus expectant management. Very early treatment of TRAP (i.e., <16 weeks) has been proposed to reduce first-trimester demise; however, this approach remains experimental. Further investigation is required to determine the best treatment and timing of intervention for TRAP.