The Outcome of Monochorionic Diamniotic Twins Discordant at 11 to 13⁺⁶ Weeks’ Gestation

Abstract

NT discordance is more predictive for adverse fetal outcome in MCDA twins than CRL discordance. Neither NT nor CRL discordance are likely to modify the intensive monitoring required for these very high-risk pregnancies.

Retrospective validation of ultrasound characteristics at 19–24 weeks as predictive tools for selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies: a diagnostic study

“…Monochorionic diamniotic (MCDA) twins represent 70% of monozygotic twins that split between 4 and 8 days after fertilization (1)(2)(3). Increased perinatal mortality and morbidity are found in MCDA twins due to shared placentation (4)(5)(6) and the presence of inter-twin placental vascular anastomoses (7). Selective intrauterine growth restriction (sIUGR) is one of the main risks in MCDA twins, and has a prevalence of 15-20% (3,8).…”

The Association between Intertwin Difference in First Trimester Crown-Rump Length, Nuchal Translucency, and Birth Weight Discordance in Twin Pregnancies: A Retrospective Cohort Study

“…Lewi et al [ 9 ] reported that differences in CRL predicted TTTS, severe discordant growth, or intrauterine death in a prospective cohort of 202 monochorionic diamniotic (MCDA) twin pregnancies. Zipori et al [ 10 ] studied 89 MCDA twin pregnancies and constructed receiver operating curves (ROC) to determine the ideal intertwin NT discordance cut points. They concluded that NT discordance > 23.7% had high a negative predictive value (86.8%) but a positive predictive value of only 52.4% for the discrimination of a composite score of adverse fetal outcomes that included death of one or both fetuses, development of TTTS, the presence of fetal anomalies, estimated fetal weight discordance > 25% at 28-week ultrasound, or birth weight discordance > 25%.…”

“…In a multicenter retrospective cohort study, Allaf et al [11] reported that NT, CRL, and combined discordances in MCDA twin pregnancies were not predictive of adverse composite obstetric and neonatal outcomes. Despite the heterogeneity in both methodology and measured outcomes for the aforementioned studies, fetal CRL and NT measurement at 11-14 weeks' gestation continues to be scrutinized as a screening method used to predict diverse pregnancy outcomes including aneuploidy, cardiac abnormalities, genetic syndromes, and TTTS [9][10][11][12][13].…”

“…In our region NT measurement, as part of early aneuploidy screening, is offered to all pregnant women as part of standard obstetrical care. As opposed to looking specifically at loss rates or adverse outcome data as has been reported previously [7][8][9][10][11][12][13], we aimed to evaluate the impact of NT and CRL discordance in twins on live births with a specific focus on intertwin growth discrepancies as this tends to proceed adverse outcomes. Thus, our primary objective was to determine whether intertwin CRL and NT discordance measured via ultrasound at 11-14 weeks gestation is associated with birth weight discordance.…”

Retrospective validation of 11–13 weeks’ gestation ultrasound characteristics as predictive tools for twin-twin transfusion syndrome and selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies

“…Monochorionic diamniotic (MCDA) twins account for 70% of monozygotic (MZ) twins that result from division between 4 to 8 days after fertilization (1)(2)(3), and are associated with increased perinatal mortality and morbidity resulting from shared placenta (4)(5)(6) and the presence of inter-twin placental vascular anastomoses (7). Twin to twin transfusion syndrome (TTTS) and selective intrauterine growth restriction (sIUGR) are the 2 main risks of MDCA, with prevalence rates of 15-20% and 15%, respectively (3,8).…”