Twin Pregnancies Complicated by a Single Malformed Fetus: Chorionicity, Outcome and Management

Abstract

T he objective of this study was to evaluate the impact of one abnormal fetus in a twin pregnancy, to compare impact of chorionicity and clinical outcome of intervention and expectant management. Thirty-seven dichorionic (DC) twins and 18 monochorionic (MC) twins complicated with one malformed fetus were evaluated for gestational age, birthweight and perinatal outcome. Six hundred and forty-two twin pregnancies were evaluated in the database. The control groups consisted of 429 DC and 86 MC twins without anomalous fetus. Mean birthweight and gestational age at birth for DC control group were (n = 429; 2137g and 34.71 weeks), DC study group, n = 37; 2117g (p = .338) and 33.97 weeks (p = .311), and DC study group with major malformations, n = 30; 2019g (p = .289) and 33.3 weeks (p = .01), and showed only significance for gestational age. There was no statistical significance between MC control group, n = 86; 2097g and 34.93 weeks, and MC study group, n = 18; 2237g (p = .338), and 34.42 weeks (p = .502). Because of limited data, the preliminary evaluation for expectant management and intervention, and survival of at least one normal fetus showed no impact. We conclude that, although, all DC twin pregnancies have a risk for preterm delivery, DC twins complicated with major malformation of one twin, have a lower mean gestational age at birth. Preliminary results for intervention does not improve fetal outcome for DC and MC twins and needs further evaluation with greater studies of impact or review.

Transabdominal selective feticide in dichorionic twins: Ten years’ experience at a single center

“…Chromosomal anomalies like trisomy 21 and 18 are associated with increased risks of miscarriage, fetal growth restriction, preterm delivery and fetal demise in multiple pregnancies . In anencephalic twins, when treated conservatively, there is a 50% risk of developing polyhydramnios, which can result in preterm labor and preterm delivery . A review that compared expectant management with SF showed significantly longer gestation periods and a higher birth weight in the SF group …”

“…In twin pregnancies discordant for genetic or congenital anomalies such as major anatomical malformation or chromosomal anomaly, in nearly 85% of cases, the anomaly is confined to one fetus, and the co‐twin is normal . There are some circumstances, however, in which the genetic or congenital anomaly present in the affected twin can be potentially threatening to the healthy co‐twin . Anencephaly, with the potential for polyhydramnios and subsequent preterm delivery, is the most common situation in which selective feticide (SF) is indicated for the management of a congenital anomaly .…”

“…Anencephaly, with the potential for polyhydramnios and subsequent preterm delivery, is the most common situation in which selective feticide (SF) is indicated for the management of a congenital anomaly . The presence of one anomalous fetus in a twin pregnancy significantly increases the risk of preterm delivery and perinatal mortality, and this risk increases with the severity of the anomaly . So, before the twins are screened, the parents should be informed about the possible implications of discordant results and the available options, which include expectant management, termination of the whole pregnancy, or SF …”

Chromosomal aberrations and CNVs in twin fetuses with cardiovascular anomalies: Comparison between monochorionic diamniotic and dichorionic diamniotic twins

“…Best and Rankin reported that the risk of developing CHD is increased by 172% for MC twins and by 49% for DC twins compared with singletons. The anomalies are frequently complex, and they are often associated with poor perinatal outcomes …”

“…The anomalies are frequently complex, and they are often associated with poor perinatal outcomes. 19,20 In this cohort, there was a differential distribution of cardiovascular anomalies in MCDA and DCDA groups. Primary structural defects such as VSD/AVSD, TOF, and UIH/SA were more common in DCDA group than those in MCDA group.…”