Selective feticide in monochorionic pregnancies: toys for the boys or standard of care?

Successful ablation of acardiac twin with Histoacryl

OBJECTIVE

Acardiac twin occurs in 1:35,000 pregnancies. Several techniques have been described to treat this condition. Some techniques have been suggested as golden standard; however, new are still being tried.

CASE REPORT

This is a case of a 32-year-old patient who had successful ablation of the acardiac twin with Histoacryl. The diagnosis of the acardiac twin was made in the 11 weeks + 3 weeks of pregnancy. Due to the development of myocardial hypertrophy and pericardial transudate of the pumping fetus, we had performed ablation of the acardiac twin with Histoacryl in the 21 weeks' +5 weeks' gestation. The procedure was uneventful, and the healthy fetus had no signs of distress. In the 33 weeks' +5 weeks' gestation, she had Cesarean section due to distress of the healthy fetus. The female baby was healthy, weighing 2380 g, Apgar score 9/10. The mummified mass of acardiac fetus weighted 300 g. Nine months later, the child is doing well.

CONCLUSION

Histoacryl is suitable for the ablation of an acardiac twin. Further studies are needed to prove the efficacy of this technique.

[Selective termination of pregnancy for monochorionic twins: a national survey of professional practice]

OBJECTIVES

Selective Termination of Pregnancy (STOP) for discordant fetal condition in monochorionic twin pregnancy is a rarely performed procedure raising technical and ethical considerations. There are no epidemiological data available in France concerning STOP and no guideline or scientific consensus on how or when to perform has been published.

MATERIALS AND METHODS

We conducted a study of national practice using a declarative questionnaire sent by e-mail to each medical coordinator of every 48 Multidisciplinary Center for Prenatal Diagnosis in France. The questions focused on the issues of 2010 and 2011. Two reminders were sent in case of no answer.

RESULTS

The response rate to the questionnaire was 56 %; 81 % of centers have experienced at least once during the two years 2010-2011 a discordant fetal anomaly in monochorionic twin pregnancy. Only 59 % of centers perform all the techniques of STOP. When interruption of the umbilical blood flow is considered, bipolar forceps coagulation is the most used (75 %). Achieving STOP during a cesarean section is a common practice (75 % of centers). Locoregional anesthesia is the preferred mode of anesthesia for STOP.

DISCUSSION AND CONCLUSION

STOP on monochorionic twin pregnancy is not practiced in all Multidisciplinary Center for Prenatal Diagnosis in France. The most widely practiced and most studied technique is bipolar forceps coagulation. The option of an expectant management should always be considered and its risks should be balanced with those of STOP. The practice of STOP during cesarean section is not unusual.

Differences between selective termination of pregnancy and fetal reduction in multiple pregnancy: a narrative review

Although selective termination of pregnancy and fetal reduction in multiple pregnancy both involve the termination in utero of the development of live fetuses, these two procedures are different in several aspects. Nevertheless, several authors tend to amalgamate and confuse their psychosocial consequences and the ethical issues they raise. Therefore, this narrative review, derived from a comparative analysis of 91 articles, shines a light on these amalgamations and confusions, as well as on the medical, contextual, experiential and ethical differences specific to selective termination and fetal reduction.

Radiofrequency driven cord occlusion for selective termination of pregnancy: evaluation in the fetal sheep

OBJECTIVE

This study was designed to assess the ability of an ultrasound-guided radiofrequency (RF)-driven procedure to induce complete and irreversible cord occlusion using a 90 days fetal sheep model.

STUDY DESIGN

Twenty 90 days gestation sheep underwent general anesthesia. The first ten fetuses were exposed under hysterotomy, and RF electrode was inserted visually in the middle of the umbilical cord and deployed. Fetuses were then replaced into the amniotic fluid and RF procedure (average target temperature of 100 degrees C during 10 minutes) was applied. For the next ten fetuses, RF electrode was inserted into the cords under trans-parietal ultrasound guidance and the same RF procedure was applied. Cord occlusion was assessed by Doppler examination (absence of cordonal flows at the end of the procedure and until fetal heart failure occurred) and by subsequent histopathological analysis.

RESULTS

Cord occlusion was always complete at Doppler examination at the end of RF procedure for the ten experiments realized under hysterotomy. No cordonal reperfusion was observed until fetal heart failure. Histopathological analysis confirmed cordonal occlusion at the site of impact. Neither cordonal rupture nor cordonal bleeding was observed for any of the ten experiments. When RF electrode was inserted under ultrasound guidance, complete occlusion could be obtained only for 6 of the ten experiments.

CONCLUSION

Our results suggest that RF might be an appropriate method for selective termination of pregnancy. Yet, optimal insertion of the electrode is required to engender a complete and irreversible cord occlusion, and ultrasound-guidance training seems necessary before current human application.

Selective cord coagulation in acardiac twins

The twin reverse arterial perfusion (TRAP) sequence is a serious complication of monochorionic multiple pregnancies in which the affected twin is reversely perfused from the healthy co-twin, resulting in severely abnormal or absent cardiac development, severe malformations, and massive hydrops fetalis. The acardiac twin threatens the survival of the pump twin either by increasing the risk of congestive cardiac failure or by the development of polyhydramnios, preterm premature rupture of membranes, preterm labour and premature delivery. A wide spectrum of surgical interventions has been applied in the management of TRAP; however, because of the rarity of this condition and the heterogeneity of its presentation, no single technique has been shown to be unequivocally optimal. In our experience, fetoscopic laser coagulation of the placental vascular anastomoses or the umbilical cord of the acardiac twin, with the possibility of applying bipolar forceps as an additional minimally invasive surgical technique, offers an effective treatment option in the management of the TRAP sequence; this treatment has a survival rate of 80%, and 67% of pregnancies with surviving pump twins go beyond 36 weeks of gestation without further complications.

Application of QF-PCR for the prenatal assessment of discordant monozygotic twins for fetal sex

OBJECTIVE

To establish the utility of quantitative fluorescent polymerase chain reaction (QF-PCR) in order to determine the zygosity of multiple pregnancies, as well as to define the origin of the most frequent aneuploidies in amniotic fluid samples.

METHODS

We describe the case of a monochorionic (MC) diamniotic (DA) pregnancy with phenotypically discordant twins (nuchal cystic hygroma and non-immune hydrops in twin A and no anomalies in twin B). QF-PCR was performed for rapid prenatal diagnosis in uncultured amniocytes and subsequently in cultured cells. Polymorphic markers for chromosomes X, Y, 13, 18 and 21 were used for determination of zygosity as well as sex chromosome aneuploidy.

RESULTS

Twin A showed a Turner Syndrome (TS) mosaicism pattern by QF-PCR in uncultured amniocytes. The monozygotic origin of the pregnancy was determined. Interphase fluorescence in situ hybridization (I-FISH) in this sample showed a mosaicism X0/XY (83/17%). Cytogenetic analysis revealed a 45,X0 karyotype in twin A and a 46,XY karyotype in twin B.

CONCLUSIONS

QF-PCR is a reliable tool for the determination of the zygosity independently of the chorionicity and the fetal sex in case of twin pregnancy. Testing both direct and cultured cells can provide useful results for genetic counselling in chromosomal mosaicisms.

Dilemmas in the management of twins discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation

OBJECTIVE

To help develop an evidence-based approach to the best management of twin pregnancies discordant for anencephaly.

METHODS

We retrospectively examined the management and outcome of 18 pregnancies discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation in our center. We combined these data with those from other publications. In total, there were 44 dichorionic pregnancies that were managed expectantly (n = 35) or by selective feticide (n = 9) and 19 monochorionic pregnancies that were managed expectantly. We also reviewed the literature to ascertain the outcome of monochorionic twin pregnancies undergoing cord occlusion.

RESULTS

In the 35 dichorionic pregnancies that were managed expectantly, 20 (57.1%) developed polyhydramnios at 25-31 weeks; 13 were managed expectantly, five had amniodrainage and two had selective feticide. In 34 of the 35 cases the non-anencephalic twin was liveborn at a median gestation of 36 (range, 28-39) weeks and in six (17.6%) of these it was born before 33 weeks. In the dichorionic pregnancies that had selective feticide, there was one miscarriage and eight (88.9%) live births at a median gestation of 37 (range, 30-40) weeks and in one (12.5%) of these it was born before 33 weeks. In the monochorionic pregnancies, four (21.1%) anencephalic fetuses died at 20-32 weeks and in three of these the normal co-twin also died. In the 16 (84.2%) cases resulting in the live birth of the normal twin, delivery occurred at a median gestation of 33 (range, 27-39) weeks and in six (37.5%) of these it was before 33 weeks. Ultrasound-guided bipolar cord coagulation in 92 pregnancies, mostly complicated by twin reversed arterial perfusion sequence or severe twin-to-twin transfusion syndrome, was associated with a survival rate of 77.2% and early preterm delivery rate of 31.0%.

CONCLUSION

Dichorionic twins discordant for anencephaly are best managed with serial ultrasound examinations for early diagnosis of polyhydramnios, which can then be treated either by amniodrainage or selective feticide. In monochorionic twins it is uncertain whether the best management is expectant or by cord occlusion.

Twin reversed arterial perfusion: fetoscopic laser coagulation of placental anastomoses or the umbilical cord

OBJECTIVE

To assess the feasibility and outcome of fetoscopic laser coagulation in pregnancies with twin reversed arterial perfusion (TRAP) sequence.

METHODS

In a prospective multicenter study, percutaneous fetoscopic laser coagulation of placental anastomoses (n = 18) or the umbilical cord of the acardiac twin (n = 42) was performed in 60 consecutive pregnancies at a median gestational age of 18.3 (range, 14.3-24.7) weeks under local or locoregional anesthesia.

RESULTS

Vascular coagulation with arrest of blood flow was achieved in 82% (49/60) of cases by laser alone and in a further 15% (9/60) by laser coagulation in combination with bipolar forceps. The overall survival rate of the pump twin was 80% (48/60). Median gestational age at delivery was 37.4 (range, 23.7-41.4) weeks and the median interval between the procedure and delivery was 18.2 (range, 1.1-25.7) weeks. Median birth weight was 2720 (range, 540-3840) g. Preterm premature rupture of membranes before 34 weeks' gestation occurred in 18% (11/60) at a median of 62 (range, 1-102) days after the procedure. However, only two (3%) women delivered within 28 days of the procedure.

CONCLUSIONS

Fetoscopic laser coagulation of placental vascular anastomoses or the umbilical cord of the acardiac twin is an effective treatment of TRAP sequence, with a survival rate of 80%, and 67% of pregnancies with surviving pump twins going beyond 36 weeks' gestation without further complications.

Ultrasound-guided radiofrequency-driven umbilical cord occlusion: an in-vitro study

OBJECTIVES

To assess the ability and safety of radiofrequency (RF) to induce cord thermal lesions using in-vitro perfused umbilical cords.

METHODS

Nineteen human term umbilical cords were cannulated at both ends and perfused continuously with saline serum in a saline serum bath (37 degrees C). The RF electrode was then inserted into the cord close to the umbilical vein. Different RF power and temperature controls were applied to determine the optimal RF procedure in terms of cord tissue injury and safety in nine experiments. The safety of RF procedures was investigated in ten cords by measuring temperature changes at different sites close to the RF electrode insertion and the impact of RF on cord narrowing was evaluated by continuous monitoring of intraluminal pressure. Subsequent histopathological analysis was carried out in all cases.

RESULTS

The optimal RF procedure reached a temperature of 100 degrees C in 10 min. RF produced a significant increase in intraluminal pressure (from 54.2 +/- 16.4 mmHg at baseline to 118.3 +/- 42.7 mmHg after 10 min, P < 0.05). There was no significant increase in temperature next to the site of insertion during the RF procedure. Histopathological analysis confirmed a > 30% decrease in cord and vein diameter. Cord tissue lesions were characterized by damage in the vessel walls and in the surrounding Wharton's jelly.

CONCLUSION

Our results suggest that RF might be a feasible and safe technique to induce occlusion of umbilical vessels. Further in-vivo experiments are needed to assess its ability to induce a complete occlusion of the umbilical cord.

Selective termination procedures in monochorionic pregnancies

Monochorionic twins have placental anastomoses that to varying degrees create a common circulation. This presents unique challenges for the performance of selective fetal termination in cases of twin-twin transfusion syndrome, twin reversed arterial perfusion sequence, or discordant twin abnormalities. Multiple methods of interrupting the affected twin's circulation have been attempted with variable success. One of the most frequent complications of any approach is iatrogenic preterm premature rupture of membranes. Laser coagulation in the midtrimester appears to be safe and effective; however, it is only available at limited centers. Currently, bipolar coagulation is the method of choice in the second half of pregnancy. The recently reported technique of radiofrequency ablation appears to be successful with minimal complications. Exploration of further percutaneous and noninvasive techniques, as well as interventions to decrease the morbidity arising from preterm membrane rupture, may lead to increased survival of the remaining twin and reduced risk of maternal complications.

Selective feticide in complicated monochorionic twin pregnancies using ultrasound-guided bipolar cord coagulation

OBJECTIVE

To review our experience with selective feticide in complicated monochorionic (MC) twin pregnancies, using ultrasound-guided cord coagulation with a bipolar forceps.

DESIGN

Retrospective analysis.

SETTING

All consecutive umbilical cord coagulations performed at our institution in the second trimester of pregnancy between November 1999 and 2003.

POPULATION

Consecutive cases of complicated MC pregnancies with an indication for selective termination.

METHODS

Ultrasound-guided coagulation of the umbilical cord with a 2.5-mm bipolar forceps under local anaesthesia.

MAIN OUTCOME MEASURES

Indications, gestational age at the procedure, perinatal outcome and neonatal follow up.

RESULTS

Forty-six patients with MC twin pregnancies underwent this procedure. Indications included twin reverse arterial perfusion sequence (n= 17), severe malformation in one twin (n= 7) and agonal presentation or cerebral anomalies of one twin in twin-to-twin transfusion syndrome (TTTS) after laser treatment or serial amniodrainage (n= 22). The procedure resulted in six intrauterine fetal demise (IUFD, 13%), with a rate of 41% and 3% when performed at 16-17 weeks or later, respectively (Fisher P= 0.002). Preterm rupture of the membranes (PROM) before 28 weeks and between 28 and 34 weeks occurred in 9% and 14% of the cases, respectively. All neonatal deaths (four) occurred in cases with PROM at 28 weeks or earlier. Paediatric follow up showed that all infants discharged alive but one were neurologically normal at 3-42 months, which corresponds to 70% of the 46 cases.

CONCLUSIONS

This technique is effective when the natural history is likely to severely affect the development of the normal co-twin. The overall intact survival rate was 70% and our results support justification of later surgery. Prematurity remains a significant complication of the procedure.

Invasive Antenatal Interventions in Complicated Multiple Pregnancies

Multiple pregnancies still pose challenging problems for modern medicine. Complications in monochorionic multiple pregnancies have sparked a revival of fetoscopy as a means surgery on the placenta and umbilical cord. As such, fetoscopic laser coagulation is currently the best first-line treatment for severe twin-to-twin transfusion syndrome. Also, fetoscopic or ultrasound-guided cord coagulation seems to be an effective technique for selective feticide in monochorionic twins, albeit with still considerably higher fetal loss rates compared with selective feticide by potassium chloride injection in dichorionic twins.

Successful selective termination at 17 weeks' gestation in monochorionic monoamniotic twin pregnancy affected by twin-twin transfusion syndrome and discordant for hypoplastic left heart syndrome

OBJECTIVES

To report a successful selective feticide in a complicated monochorionic monoamniotic (MCMA) pregnancy.

METHODS

A case of MCMA pregnancy with severe twin-twin transfusion syndrome and discordant for hypoplastic left heart syndrome was diagnosed at 16 weeks' gestation. A complete ultrasound and fetoscopic surveillance was performed, ruling out cord entanglement and, thus, precluding the necessity of transecting the cord.

RESULTS

The selective feticide was successfully performed by bipolar coagulation of the umbilical cord of the abnormal fetus under ultrasound guidance. The survivor twin developed normally during the rest of the pregnancy and was born at term. At 6 months of age, the infant was healthy.

CONCLUSION

Selective feticide in complicated monoamniotic pregnancies can be safely performed. Cord entanglement can be confidently excluded by both ultrasound and fetoscopy, thus making the systematic transection of the umbilical cord unnecessary.