Bases informacionales para el estudio morfométrico de placentas en embarazos gemelares

RESUMEN Introducción: En Cuba existen muy pocos estudios morfofuncionales de placentas procedentes de embarazos gemelares que permitan establecer un patrón morfométrico general. Implementar estas bases informacionales contribuiría a perfeccionar las acciones del Programa Nacional de Salud Sexual y Reproductiva en el país. Objetivo: Sistematizar información sobre estudios morfométricos en placentas gemelares para construir la base epistémica de la caracterización del patrón morfométrico de las placentas gemelares y su relación con la corionicidad, la función de este órgano y el grado de bienestar fetal y neonatal. Método: Se aplicó una estrategia de búsqueda en el período enero de 2020 hasta abril de 2021, en bases de datos internacionales (Medline, EMBASE, LILACS, Scopus, Google Académico) para la revisión bibliográfica, mediante la utilización del método de análisis y crítica de las fuentes desde el procedimiento de análisis de contenido. Se empleó un algoritmo para la toma de decisiones en torno a la pertinencia, actualidad novedad y aportes. Resultados: Se hallaron 16 fuentes bibliográficas sobre el tema de investigación, entre ellas: solo una tesis (6,25 %) y 4 textos editados (25 %). Predominaron los artículos científicos (68,75 %) de los últimos cinco años (93,75 %). Todas las fuentes contribuyeron a la construcción de los referentes teóricos. Conclusiones: El estudio morfométrico de la placenta en embarazos gemelares es un área insuficientemente desarrollada en el conocimiento de las ciencias básicas biomédicas, dada la escasa producción bibliográfica sobre el tema.

ABSTRACT Introduction: In Cuba there are very few morphofunctional studies of placentas from twin pregnancies that allow establishing a general morphometric pattern. Implementing these informational databases would help to improve the actions of the National Sexual and Reproductive Health Program in the country. Objective: To systematize information on morphometric studies in twin placentas to build the epistemic basis for the characterization of the morphometric pattern of twin placentas and its relationship with chorionicity, the function of this organ and the degree of fetal and neonatal well-being. Method: A search strategy was applied in the period January 2020 to April 2021, in international databases (Medline, EMBASE, LILACS, Scopus, Google Scholar) for the bibliographic review, using the analysis and criticism method. of the sources from the content analysis procedure. An algorithm was used to make decisions about relevance, news, news and contributions. Results: 16 bibliographic sources were found on the research topic, among them: only one thesis (6.25%) and 4 edited texts (25.0%). Scientific articles (68.75%) from the last five years (93.75%) predominated. All the sources contributed to the construction of the theoretical referents. Conclusions: The morphometric study of the placenta in twin pregnancies is an insufficiently developed area in the knowledge of basic biomedical sciences, given the scarce bibliographic production on the subject.

RESUMO Introdução: Em Cuba existem poucos estudos morfofuncionais de placentas de gestações gemelares que permitam estabelecer um padrão morfométrico geral. A implementação desses bancos de dados informativos ajudaria a melhorar as ações do Programa Nacional de Saúde Sexual e Reprodutiva no país. Objetivo: Sistematizar informações sobre estudos morfométricos em placentas gêmeas para construir a base epistêmica para a caracterização do padrão morfométrico de placentas gêmeas e sua relação com a corionicidade, a função desse órgão e o grau de bem-estar fetal e neonatal. Método: Foi aplicada uma estratégia de busca no período de janeiro de 2020 a abril de 2021, em bases de dados internacionais (Medline, EMBASE, LILACS, Scopus, Google Scholar) para a revisão bibliográfica, utilizando o método de análise e crítica das fontes da análise de conteúdo procedimento. Um algoritmo foi usado para tomar decisões sobre relevância, notícias, notícias e contribuições. Resultados: Foram encontradas 16 fontes bibliográficas sobre o tema da pesquisa, entre elas: apenas uma tese (6,25%) e 4 textos editados (25,0%). Predominaram artigos científicos (68,75%) dos últimos cinco anos (93,75%). Todas as fontes contribuíram para a construção dos referentes teóricos. Conclusões: O estudo morfométrico da placenta em gestações gemelares é uma área pouco desenvolvida no conhecimento das ciências biomédicas básicas, dada a escassa produção bibliográfica sobre o assunto.

Importancia social del estudio morfométrico en placentas procedentes de embarazos gemelares / Social importance of the morphometric study in placentas from twin pregnancies / Importância social do estudo morfométrico em placentas de gestações gemelares

RESUMEN Se fundamenta la necesidad de la investigación científica para el estudio morfométrico en placentas procedentes de embarazos gemelares, como aproximación a la correlación entre el patrón morfométrico, la corionicidad y el bienestar fetal y neonatal, en tanto criterios básico/clínicos a tomar en cuenta para perfeccionar las acciones del programa nacional de salud sexual y reproductiva en Cuba. Se destaca la importancia social de un diseño de investigación en este campo, al constatar las carencias epistémicas desde una búsqueda sistematizada de información bibliográfica sobre el tema.

ABSTRACT The need for scientific research for the morphometric study in placentas from twin pregnancies is founded, as an approximation to the correlation between the morphometric pattern, chorionicity and fetal and neonatal well-being, as basic / clinical criteria to be taken into account to improve the actions of the national sexual and reproductive health program in Cuba. The social importance of a research design in this field is highlighted, when verifying the epistemic deficiencies from a systematized search of bibliographic information on the subject.

RESUMO Fundamenta-se a necessidade de pesquisas científicas para o estudo morfométrico em placentas de gestações gemelares, como uma aproximação da correlação entre o padrão morfométrico, corionicidade e bem-estar fetal e neonatal, como critérios básicos / clínicos a serem levados em consideração para melhorar a ações do programa nacional de saúde sexual e reprodutiva em Cuba. Ressalta-se a importância social de um desenho de pesquisa nessa área, ao verificar as deficiências epistêmicas a partir de uma busca sistematizada de informações bibliográficas sobre o assunto.

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.

Study of maternal and perinatal outcome among twin pregnancies with one twin demise

Background: To study the incidence, management and to determine maternal and perinatal outcome in cases of twin pregnancy with one twin demise in the second half of the pregnancy.Methods: This retrospective study was carried out at Cheluvamba Hospital, a tertiary care hospital attached to Mysore medical college and research institute between September 2009 and 2014. 19 twin pregnancies complicated by single intrauterine fetal demise (IUFD) after 20 weeks of gestation were identified from the hospital records. Data collected included maternal age, parity, antenatal complications, cause of IUFD, gestational age at diagnosis, time interval between diagnosis of IUFD and delivery, mode of delivery, birth details, type of placentation and neonatal complications.Results: The incidence of twin with one twin demise was 2.056%. Mean gestational age at presentation was 33.86 weeks. Most common cause of death was growth discordance in 7 cases followed by placental insufficiency in 4 cases. 57.89% of cases had monochorionic placentation. Neonatal course was most commonly complicated by prematurity. Maternal course was uneventful in majority (63.15%) of cases with two maternal deaths due to intravascular coagulopathy sequelae.Conclusions: Single fetal death occurs more often in monochorionic twins. The main problem for the surviving twin is prematurity. It is very important to identify the chorionicity by ultrasound examination in early pregnancy and implement specific surveillance of monochorial pregnancies.

Diagnóstico ecográfico de la corionicidad y amnionicidad en el embarazo múltiple

La determinación ecográfica de la corionicidad y de la amnionicidad constituye la piedra angular en el manejo obstétrico del embarazo múltiple. Esta debe hacerse en el primer trimestre del embarazo, no solamente por la mayor facilidad diagnóstica sino sobretodo porque constituye el inicio de la ruta a seguir en el control de este tipo de gestaciones. Por lo mencionado anteriormente, el profesional que lidie con esta clase de ecografías debe disponer de los conocimientos necesarios para llegar a un diagnóstico certero de la corionicidad y amnionicidad por ultrasonido.

Determination of chorionicity and amnionicity by ultrasound is the most important step in the management of multiple pregnancies. This diagnosis should be done in the first trimester of pregnancy not only because less difficulty but because it constitutes the beginning ofvarious steps in the control of these types of pregnancies. It is highly recommended that professionals dealing with this kind of study have the knowledge to assess correctly and promptly chorionicity and amnionicity in multiple pregnancies.

Doppler assessment of fetal aortic isthmus flow in twin

OBJECTIVE: The purpose of this study was to investigate the aortic isthmus (AoI) flow difference between larger fetus and smaller fetus of twin; and to evaluate the predictive value of early diagnosis of hemodynamic change in twin growth. METHODS: This prospective study on 49 pairs of twin fetuses was performed to obtain AoI blood flow data. Cases with structural or chromosomal abnormalities and co-twin death were excluded. The interval from examination to delivery was within 4 weeks and 3 cases over 4 weeks interval were re-examined. Assessment of fetal AoI Doppler parameters were peak systolic velocity (PSV), end-diastolic velocity, times-averaged maximum velocities, pulsatility index (PI), and resistance index (RI). According to the direction of the diastolic flow in the AoI, antegrade and retrograde flow were made and was used to analyze the perinatal outcomes of each fetus. The predictive value of AoI Doppler parameters in predicting fetal growth was obtained by using ANOVA and logistic regression analysis of quantitative variables in each fetus of twins. RESULTS: There were significant differences in the gestational weeks at delivery, birth weight and the incidence of growth discordance over 20% or more between monochorionic twin and dichorionic twin. The AoI PI and RI were significantly higher in smaller fetus than in larger regardless of chorionicity. Retrograde flow was noted in 8 of 98 cases (8.2%) and the only one case was of the larger fetus and the others were smaller fetuses of twin. Significant correlations were found between the AoI PI and birthweight (P=0.018) and between the PSV and growth discordance (P=0.032). In monochorionic twin, linear correlation was shown between the AoI PI and birthweight (P=0.004) and between AoI PI and growth discordance (P=0.031). Also, the meaningful correlation between the PSV and birthweight (P=0.036) was found by using logistic regression analyses. CONCLUSION: On the basis of our observation, AoI PI has revealed their hemodynamic status and this result may improve the understanding of growth patterns in twins.

Congenital Malformations in Twins: Effect of Chorionicity and Zygosity.

Twins suffer a high risk of congenital malformations but the data from our region is scanty. In this study, 133 twin pairs (266 twin babies) were studied and a 3.4% incidence of malformations was seen without gender preference. There was no association of chorionicity and zygosity with the risk for having congenital malformations

The rate and etiologies of second trimester fetal loss in twin pregnancies / 대한산부인과학회지

OBJECTIVE: To evaluate and compare the rate and etiologies of second trimester pregnancy loss in monochorionic (MC) or dichorionic (DC) twins, and natural or assisted reproductive technology (ART) twins. METHODS: Between January 1997 and December 2008, there were 146 cases of second trimester twin pregnancy losses (between 12 and 24 weeks gestation) from 2,467 twin pregnancies. They were divided into four groups according to chorionicity and fertilization. Chorionicity was established by ultrasound at early gestation and confirmed by histologic examination after delivery. From a total of 2,467 twin deliveries, 392 MC, 2058 DC, and 17 unknown chorionicity were observed. Fertilization methods were classified as 736 natural, 1,590 ART, and 141 unknown conceptions. The pregnancy loss rate and possible mechanisms were compared in each group. RESULTS: During the study period, there were 43 MC, 86 DC, and 17 unknown chorionicities and 45 natural, 78 ART, and 23 unknown fertilizations. Total twin pregnancy loss rate was 5.9% (146/2,467), with 11.0% (43/392) and 4.2% (86/2,058) for MC twin group and DC twin group, respectively. Likewise, it was 6.1% (45/736) and 4.9% (78/1,590) for natural twin group and ART twin group. The most common cause was intrauterine fetal death (IUFD) in 22 (51.2%) in MC twin group and preterm premature rupture of membranes (PPROM) in 40 (46.5%) in DC twin group, followed by preterm labor (PTL) in 37 (43%). In natural pregnancy, IUFD was the most common etiology in 20 (44.5%) and for ART twin group, it was PTL in 35 (44.9%). CONCLUSION: Twin pregnancy loss rate was higher in MC twin group compared with DC twin group in the second trimester. MC twin group had a higher incidence of IUFD as a cause of second trimester pregnancy loss. The etiologies in DC twin group were PPROM and PTL. It is suggested that antenatal care in twin pregnancy should be explored for preventing fetal loss and promoting neonatal well-being.

Perinatal outcomes of birth weight discordance according to the chorionicity / 대한산부인과학회지

OBJECTIVE: The purpose of this study was to examine the association between intrapair birth weight discordance and perinatal outcomes according to the chorionicity. METHODS: Twin births in St. Vincent's Hospital of Catholic University of Korea for the period 2000~2007 were retrospectively studied. Discordance was defined as an intertwin birth weight difference > or =20% and concordance was defined as weight difference <20% calculated from the larger newborn. Perinatal outcomes were compared between discordant and concordant pairs in monochorio-diamnionic and dichorionic twins. RESULTS: Among 38 monochorionic twin births, 34.2% was discordant and 66.8% was concordant. Among 144 dichorionic twin birth, 9.9% was discordant and 91.9% was concordant. The incidences of intrauterine fetal death (FDIU), twin-to-twin transfusion syndrome (TTTS), intrauterine growth restriction (IUGR) and neonatal hypoglycemia of discordant group of monochorionic twins were statistically increased compared with concordant group of monochorionic twins. The incidences of IUGR and neonatal hypoglycemia were statistically increased in the discordant group of dichorionic twins compared with concordant group of dichorionic twins. The others were not shown statistically significant between two groups in the both chorionic twins. CONCLUSIONS: Birth weight discordance in monochorionicity seems to predict fetal death, TTTS, IUGR and newborn hypoglycemia. Birth weight discordance in dichorionicity does not seem to be good predictor of adverse perinatal outcomes except IUGR and neonatal hypoglycemia.

Tailored selective termination in second trimester in twin pregnancy / 대한산부인과학회지

OBJECTIVE: Recently, selective termination is employed in multifetal pregnancies, in the presence of an abnormal fetus, or in the complication of twin pregnancies. The purpose of this study is to evaluate effectiveness, safety of the tailored selective termination in multifetal pregnancies. METHODS: This study was retrospective and involved six cases. Indication of termination were 3 cases of structural anomalies (anencephaly, encephalocele, body stalk anomaly), 1 case of chromosomal anomaly (21 trisomy) and 2 cases of monochorionic twin complications (acardiac twin, twin to twin transfusion syndrome). RESULTS: We used KCL injection in 4 cases, they were all confirmed dichorionic twin, and in 2 cases of monochorionic twin, we used alcohol ablation of intra-abdominal umbilical artery in 1 case, and radiofrequency ablation of the cord in 1 case. CONCLUSION: All procedures were successful, and all normal infants were delivered in 3rd trimester. Tailored selective termination in 2nd trimester is effective and safe in abnormal multifetal pregnancies.

Comparison of pregnancy outcomes based on chorionicity between spontaneous and in vitro fertilization twins / 대한산부인과학회지

OBJECTIVE: To compare the pregnancy outcomes of in vitro fertilization (IVF) twins with those of spontaneous twins based on their chorionicities. METHODS: We performed a retrospective analysis of 598 twin pregnancies beyond 24 weeks of gestation delivered from October 1994 to December 2003. Subjects were grouped into the spontaneous group (n=392) and the IVF group (n=206) and then subgrouped into dichorionic (n=193, spontaneous vs. n=156, IVF) and monochorionic (n=154, spontaneous vs. n=34, IVF) subgroups. First, the obstetric and perinatal outcomes were compared between the spontaneous group and the IVF group regardless of their chorionicity. Second, the same outcome variables were compared between the spontaneous and the IVF group with same chorionicity. RESULTS: There was a significant increase in the incidence of preterm deliveries before 37 weeks of gestation in IVF twins (74.5% spontaneous vs. 82.5% IVF, p=0.031). However, the gestational age at delivery was not significantly different (34.5+/-2.86 weeks vs. 34.2+/-0.28 weeks). Antepartum admission was also significantly increased in IVF group (4.6% vs. 9.2%, p<0.001). We were unable to observe any significant difference in perinatal outcomes between the two groups other than increased in utero fetal demise in utero in the IVF group (0.3% vs. 1.5%, p<0.05). When we reanalyzed pregnancy outcomes based on chorionicity, there were more frequent admission to neonatal intensive care unit (42.7% vs. 52.6%, p<0.05) and necrotizing enterocolitis (0.5% vs. 3.5%, p<0.05) in dichorionic twins of the IVF group. In monochorionic twins, the incidence of placenta previa was increased in the IVF twin group (0% vs. 11.8%, p<0.001). CONCLUSION: In the IVF twins, the incidence of placenta previa was increased in monochrionic twins and the incidence of neonatal intensive care unit admission and necrotizing enterocolitis were also increased in dichorionic twins.

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.

Twin Pregnancies with One Fetal Demise / 대한산부인과학회잡지

OBJECTIVE: To evaluate the maternal complications and perinatal outcomes in twin pre-gnancies with one fetal demise PATIENTS: From January 1990 to December 1996, 20 twin pregnancies with single fetal death were observed in Seoul National University Hospital : in 6 cases(group 1) between 20 ~26 weeks and in 14 cases(group 2) after 26 weeks gestation by gestational age of fetal death ; in 7 cases of monochorionic and in 13 cases of dichorionic placentation. RESULTS: The incidence of one fetal death was 5.4% in twin pregnancy. Diagnosis-to- delivery interval of group 1 was longer than group 2(61.0 days : 8.9 days). So it was thou- ght that the gestational age of delivery in group 1 was not always earlier than in group 2. And other parameters(chorionicity, preterm delivery, cesarean section, coagulopathy, IUGR, perinatal mortality, neurologic sequelae, IVH) didn't show the statistical differences between group 1 and group 2. According to chorionicity, it seemed that the perinatal mortality rate of monochorionic group was higher than dichorionic(86% : 62%) and that cesarean section rate was higher in dichorionic group(54% : 14%). But there were no statistical significances between two gruops. All other parameters also didn't show differences statistically. CONCLUSION: We fail to demonstrate that monochorionic placentation is associated with increased risks for the survivor in twin pregnancies of single fetal demise. It may be part- ially explained due to small numbers of cases in this study.