High Risk of Unexpected Late Fetal Death in Monochorionic Twins Despite Intensive Ultrasound Surveillance: A Cohort Study

Abstract

BackgroundThe rationale for fetal surveillance in monochorionic twin pregnancies is timely intervention to prevent the increased fetal/perinatal morbidity and mortality attributed to twin–twin transfusion syndrome and intrauterine growth restriction. We investigated the residual risk of fetal death after viability in otherwise uncomplicated monochorionic diamniotic twin pregnancies.Methods and FindingsWe searched an electronic database of 480 completed monochorionic pregnancies that underwent fortnightly ultrasound surveillance in our tertiary referral fetal medicine service between 1992 and 2004. After excluding pregnancies with twin–twin transfusion syndrome, growth restriction, structural abnormalities, or twin reversed arterial perfusion sequence, and monoamniotic and high-order multiple pregnancies, we identified 151 uncomplicated monochorionic diamniotic twin pregnancies with normal growth, normal liquor volume, and normal Doppler studies on fortnightly ultrasound scans. Ten unexpected intrauterine deaths occurred in seven (4.6%) of 151 previously uncomplicated monochorionic diamniotic pregnancies, within 2 wk of a normal scan, at a median gestational age of 34+1 wk (weeks+days; range 28+0 to 36+3). Two of the five cases that underwent autopsy had features suggestive of acute late onset twin–twin transfusion syndrome, but no antenatal indicators of transfusional imbalance or growth restriction, either empirically or in a 1:3 gestation-matched case–control comparison. The prospective risk of unexpected antepartum stillbirth after 32 wk was 1/23 monochorionic diamniotic pregnancies (95% confidence interval 1/11 to 1/63).ConclusionDespite intensive fetal surveillance, structurally normal monochorionic diamniotic twin pregnancies without TTTS or IUGR are complicated by a high rate of unexpected intrauterine death. This prospective risk of fetal death in otherwise uncomplicated monochorionic diamniotic pregnancies after 32 wk of gestation might be obviated by a policy of elective preterm delivery, which now warrants evaluation.

The Role of Second and Third Trimester Umbilical Artery Doppler Ultrasonography in Determining Chorionicity of Twin Pregnancies

“…Therefore, early diagnosis of chorionicity is vital in twine or multiple pregnancies [6]. So, procedures have been suggested in precise monitoring of fetuses in monochorionic twin pregnancies to prevent morbidity and mortality [4,9,[11][12][13]. It should be noted, however, none of these pathologic entities were present, neither in the study by Ingec et al, nor in the present study.…”

“…The determination of chorionicity is important for predicting the prognosis of pregnancy, because it has been shown that in monochorionic cases, vascular anastomoses or imbalanced placental vascular distribution in the two placentas may lead into the twin insufficiency syndrome. In addition, hemodynamic imbalances may jeopardize the health of both fetuses and cause significant consequences [4,9,10]. A worse prognosis in monochorionic pregnancies is possibly due to the twin to twin transfusion syndrome, growth restriction, and the twin reverse arterial perfusion syndrome in such cases.…”

Non‐identical monozygotic twins, intermediate twin types, zygosity testing, and the non‐random nature of monozygotic twinning: A review

“…MZ twinning is an intrinsic feature of human reproduction. Because of the many disadvantages of MC placentation [Barigye et al, 2005], it is not clear what the evolutionary advantage of MZ twinning might be. It may merely be a phenocopy of DZ twinning, whose advantage would be a more rapid recovery per completed pregnancy following population loss through war, famine or disease.…”

Tratamiento Por Fetoscopia Del Síndrome De Transfusión Feto Fetal en Clínica Alemana De Santiago

“…A pesar de la falta de evidencia de esto, la recomendación ha sido aceptada por el Real Colegio de Obstetricia y Ginecología (21). Por otra parte, esta indicación no debe ser considerada tan extraña, pues existen estudios que reportan que los gemelares monocoriales biamnióticos, sin signos ecográficos de transfusión feto fetal, tienen una tasa de muerte fetal entre las 28 y 36 (promedio 34) semanas de hasta un 5% (22), lo que justificaría aún más una interrupción electiva a las 34-35 semanas en casos de STFF tratados por fetoscopia.…”