Twin pregnancies, crown-rump length and birthweight discordancy: the influence of chorionicity / Gestações gemelares, comprimento craniocaudal e discordância de peso ao nascimento: a influência da corionicidade

Abstract Objective The purpose of the present study was to analyze the influence of chorionicity in the biometric parameters crown-rump length (CRL), birthweight (BW), crown-rump length discordancy (CRLD) and birthweight discordancy (BWD), determine the correlation between these latter two in cases of intertwin discordancy, and to analyze the influence of chronicity in the presence of these discordancies with clinical relevance (> 10% and > 15%, respectively). Methods The present study was a retrospective study based on the twin pregnancy database of the Centro Hospitalar S. João (2010-2015), including 486 fetuses among 66 monochorionic (MC) and 177 dichorionic gestations (DC). The inclusion criteria were multiple pregnancies with 2 fetuses and healthy twin gestations. The exclusion criteria were trichorionic gestations and pregnancies with inconclusive chorionicity, multiple pregnancy with ≥ 3 fetuses and pathological twin gestations. Results No statistically significant difference was found in BW (p = 0.09) and in its discordancy (p = 0.06) nor in CRL (p = 0.48) and its discordancy (p = 0.74) between MCs and DCs. Crown-rump length discordancy and birthweight discordancy were correlated by the regression line "BWD = 0.8864 x CRLD + 0.0743," with r2 = 0.1599. Crown-rump length discordancy > 10% was found in 7.58% of monochorionic and in 13.56% of dichorionic twins. Birthweight discordancy > 15% was detected in 16.67% of monochorionic and in 31.64% of dichorionic twins. Conclusion No statistically significant influence of chorionicity was identified in both birthweight and birthweight discordancy, as in crown-rump length and crown-rump length discordancy. Birthweight discordancy was correlated to crown-rump length discordancy in 20% of cases.

Resumo Objetivo O objetivo do presente estudo foi analisar a influência da corionicidade nos parâmetros biométricos comprimento craniocaudal, peso ao nascimento, discordância de comprimento craniocaudal e discordância de peso ao nascimento, determinar a correlação entre estes dois últimos caso haja discordância intergemelar e analisar a influência da corionicidade na presença destas discordâncias com relevância clínica (> 10% e > 15%, respectivamente). Métodos O presente estudo foi um estudo retrospectivo baseado na base de dados de gestações gemelares do Centro Hospitalar S. João (2010-2015), incluindo 486 fetos de 66 gestações monocoriônicas e 177 dicoriônicas. Os critérios de inclusão foram gestações múltiplas de 2 fetos e gestações gemelares saudáveis. Os critérios de exclusão foram gestações tricoriônicas ou de corionicidade inconclusiva, gestações múltiplas com ≥ 3 fetos e gestações gemelares patológicas. Resultados Não se encontrou diferença estatisticamente significativa no peso ao nascimento (p =0,09) e sua discordância (p = 0,06) nem no comprimento craniocaudal (p = 0,48) e sua discordância (p = 0,74) entre gestações monocoriônicas e dicoriônicas. Considerando todas as gestações, as discordâncias de comprimento craniocaudal e peso ao nascimento foram correlacionadas pela reta de regressão "discordância de peso ao nascimento = 0.8864 x discordância de comprimento craniocaudal + 0.0743," com r2 = 0,1599. A discordância de comprimento craniocaudal > 10% descobriu-se em 7.58% das gestações monocoriônicas e em 13.56% das dicoriônicas. A discordância de peso ao nascimento > 15% detectou-se em 16.67% das gestações monocoriônicas e em 31.64% das dicoriônicas. Conclusão Não se identificou influência estatisticamente significativa no peso ao nascimento e sua discordância, bem como no comprimento craniocaudal e sua discordância. A discordância de peso ao nascimento correlacionou-se com a discordância de comprimento craniocaudal em 20% dos casos.

Birthweight and growth discordancy in twin pregnancies according to the type of placenta and the portion of umbilical cord insertion / 대한산부인과학회잡지

OBJECTIVE: To investigate the effect of the type of placenta and the portion of umbilical cord insertion on birthweight and growth discordancy in twin pregnancies. METHODS: We selected 120 twins of 146 multiple pregnancies between March, 2000 and March, 2002, and one fetus of all cases at least weighed 500 g or more and over 24 weeks of gestation. The fetuses were included that 44 twins (88 fetuses) had monochorionic placentas and the 76 twins (152 fetuses) had dichorionic placentas. The dichorionic twins were divided into two groups; one (38 twins, 76 fetuses) showed the fused type of placenta and the other (38 twins, 76 fetuses) showed the separate type of placenta. The types of umbilical cord insertion were also divided into the central portion and the peripheral portion, the peripheral portion was defined within 2 cm of margin of placenta, and included marginal and velamentous insertion of umbilical cord. Stastical analysis were performed with Student t-test and runs test. p<0.05 was defined significantly. RESULTS: 1. The central type of umbilical cord insertion in dichorionic placenta was more frequent than that of monochorionic placenta (p<0.01). 2. The dichorionic infants, regardless the number of placenta, who weighed more than monochorionic infants at birth (p<0.01). 3. Twin pairs with over 25% of growth discordancy were 16 cases (13.3%), which included 9 cases (9/76, 11.8%) of dichorionic placenta and 7 cases (7/44, 15.9%) of monochorionic placenta. The severe growth discordancy was more commonly developed in monochorionic twins than dichorionic twins (p<0.01). 4. Perinatal deaths in twin pairs with over 25% of GD were 12 cases, which included 3 cases (3/18, 16.7%) of dichorions, and 9 cases (9/14, 64.3%) of monochorions. Therefore, perinatal death was showed more commonly in monochorinic twin infants (p<0.01). CONCLUSION: The type of umbilical cord insertion affected the birthweight of dichorionic separated infants. Monochorionic placenta attributed to more severe growth discordancy and increased perinatal death rate than the dichorionic placenta. Antenatal detection of chorionicity and the portion of umbilical cord insertion may improve the perinatal outcome.

The Clinical Assessment of Discordant Fetal Growth in Dichorionic and Monochorionic Twins / 대한산부인과학회잡지

OBJECTIVE: The purpose of this study was to evaluate the clinical course of discordant fetal growth and perinatal outcome in relation to dichorionic and monochorionic twin for different degrees of birth weight difference. METHODS: Between Jan. 1992 and Dec, 1997, 154 twin pairs were born at Yonsei medical center and there were 36 pairs of twins which had 20% or more birth weight difference. The placental examination were performed routinely on all multiple births and 13 pairs of dichorionic twins and 23 pairs of monochorionic twins were consisted of the study population. These twin pairs were divided into three groups based on birth weight difference: 20-29%(as group A), 30-39%(as group B), and 40% or more(as group C). Gestational age, birth weight, gender and perinatal outcomes were observed for each twin pairs. RESULTS: The perinatal death in the monochorionic twin pairs showed 9(34.6%) as group A, 4(50%) as group B, and 5(41,7%) as group C and in the dichorionic twin paus 1(10.0%) as youp A, 0 as group B and 5(62.5%) as group C. Up to 40% of birth weight difference, dichorionic twin pairs showed good perinatal outcomes compared with monochorionic twin pairs but over 40% or more of birth weight diffaence, however there were no significant difference of perinatal outcomes by chorionicity. In the monochorionic twin pairs, the cause of perinatal death showed 3 cases of prematurity, 2 cases of congenital anomalies and 2 cases of IIOC and 2 cases of cord lesions in group A whenas in the group B and C 3 cases of prematurity and 6 cases of congenital anomalies. In the dichorionic twin pairs, different-sex twin pairs showed no perinatal death in all three groups but in same-sex twin pairs there were 6 perinatal deaths. CONCLUSION: More recent improved fetal ultrasonographic surveillance such as determination of chorionicity, identification of fetal sex and evaluation of fetal anomalies help to make a clinical decision in growth discordant twin up to 40% of weight difference each other.