Monochorionic Triplet Pregnancies With Twin Reversed Arterial Perfusion and Acardiac Triplet: Report of Two Cases and Literature Review

Abstract

TRAP pregnancies involving monochorionic triplets are extremely rare, calculated to be 1 in 4.5 million. We report two cases of monochorionic triplet pregnancies with an acardiac triplet. In one case, the mother was a 33-year-old G2P1 who underwent dilation and evacuation at 20 weeks due to poor prognosis. The other case involved a 21-year-old G1P0 mother presenting in advanced preterm labor at 21 weeks who elected expectant management. Seventeen cases of monochorionic triplets with TRAP were identified in the literature. Invasive intervention was performed in 10 cases; 9 cases resulted in the survival of the nonacardiac twins and 1 case resulted in the survival of 1 fetus. Our two cases had common sonographic features which included polyhydramnios of all fetuses. Placental features shared between both cases included being large for gestational age and velamentous insertion of the acardiac twin. The acardiac twins in both of our cases were hydropic and demonstrated developed pelvis and lower extremities. One had an omphalocele. Most case reports in the literature review demonstrate similar findings. Two cases of monochorionic triplets with TRAP and acardiac twin are herein described. Successful treatment by invasive interventions have been described in this condition, highlighting the importance of early diagnosis.

Early prenatal diagnosis of acardiac anomaly: A triplet case report

“…20 Two cases of monochorionic triplet pregnancies with an acardiac triplet diagnosed at 18 and 19 weeks respectively showed poor prognosis without any intervention. 23 The acardiac anomaly detectable from early pregnancy in this case was helpful for subsequent effective monitoring and the choice of intervention timing. The management for this case was successful.…”

“…It was proposed that elective intervention at an early stage before 16 weeks may improve the outcomes and reduces the frequency of adverse pregnancy outcomes. 15,[20][21][22][23] In this regard, ultrasound-guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches; the survival rate reported in untreated acardiac multiple pregnancies was about 50% or more; 70% or more after laser coagulation/radiofrequency ablation. 20 Two cases of monochorionic triplet pregnancies with an acardiac triplet diagnosed at 18 and 19 weeks respectively showed poor prognosis without any intervention.…”

“…The management of acardiac anomaly should focus on maximizing the non‐acardiac fetus' chances of survival, whereas the best timing of intervention is still controversial. It was proposed that elective intervention at an early stage before 16 weeks may improve the outcomes and reduces the frequency of adverse pregnancy outcomes 15,20–23 . In this regard, ultrasound‐guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches; the survival rate reported in untreated acardiac multiple pregnancies was about 50% or more; 70% or more after laser coagulation/radiofrequency ablation 20 .…”

“…In this regard, ultrasound‐guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches; the survival rate reported in untreated acardiac multiple pregnancies was about 50% or more; 70% or more after laser coagulation/radiofrequency ablation 20 . Two cases of monochorionic triplet pregnancies with an acardiac triplet diagnosed at 18 and 19 weeks respectively showed poor prognosis without any intervention 23 . The acardiac anomaly detectable from early pregnancy in this case was helpful for subsequent effective monitoring and the choice of intervention timing.…”