Perinatal outcome of monochorionic diamniotic twin pregnancy complicated by selective intrauterine growth restriction according to umbilical artery Doppler flow pattern: single-center study using strict fetal surveillance protocol.

OBJECTIVE: To determine the perinatal outcome of monochorionic diamniotic (MCDA) twin pregnancies complicated by selective intrauterine growth restriction (sIUGR), which were classified according to the umbilical artery (UA) Doppler flow pattern of the IUGR twin. METHODS: This was a retrospective cohort study of all MCDA twin pregnancies diagnosed with sIUGR and managed at a single tertiary referral center between 2012 and 2018. Cases were classified according to the UA Doppler flow pattern of the IUGR twin as Type I (positive end-diastolic flow), Type II (persistently absent/reversed end-diastolic flow) or Type III (intermittently absent/reversed end-diastolic flow). Patients with Type-II or -III sIUGR were hospitalized at 26-28 weeks of gestation for increased fetal surveillance. Perinatal and immediate and long-term neurodevelopmental outcomes were stratified according to the UA Doppler flow pattern at the final examination. Intact survival rate was defined as the number of infants surviving without neurological impairment, divided by the total number of fetuses. Composite adverse outcome, defined as any mortality, presence of severe brain lesions on postnatal transcranial ultrasound or severe neurological morbidity, was also assessed. RESULTS: Of 88 MCDA twin pregnancies with sIUGR included in the study, 28 underwent selective termination by cord occlusion using radiofrequency ablation, resulting in a perinatal survival rate of 89.3% and a median gestational age (GA) at delivery of 33.8 (interquartile range (IQR), 28.8-38.2) weeks for the large cotwin. Expectant management was employed in 60 cases. In 26 (43.3%) cases in the expectant-management group, the classification according to the UA Doppler flow pattern changed during gestation, resulting in 26 (43.3%) cases of Type-I, 22 (36.7%) cases of Type-II and 12 (20.0%) cases of Type-III sIUGR at the final examination. The perinatal survival rate of both twins with sIUGR Types I, II and III at the final examination was 100%, 81.8% and 75.0%, respectively (P = 0.04). Two cases of double fetal death and one case of single fetal death occurred 1-4 weeks after the Doppler pattern had changed from Type I or Type II to Type III. The median GA at delivery was 34.8 (IQR, 33.1-35.7) weeks in Type I, 30.3 (IQR, 28.6-32.1) weeks in Type II and 32.0 (IQR, 31.3-32.6) weeks in Type III (P < 0.01). The total intact survival rate was 100% for Type I, 77.3% for Type II and 75.0% for Type III (P < 0.001). Multivariate analysis demonstrated that early GA at diagnosis (odds ratio (OR), 0.83 (95% CI, 0.69-0.99); P = 0.04) and the presence of Type II or III vs Type I at the last examination (OR, 13.16 (95% CI, 1.53-113.32); P = 0.02) were associated with preterm birth < 32 weeks' gestation. Early GA at diagnosis was also associated with the composite adverse outcome (OR, 0.60 (95% CI, 0.36-0.99); P = 0.04). CONCLUSIONS: The classification system of MCDA pregnancy complicated by sIUGR, according to the UA Doppler flow pattern of the IUGR twin at final examination, is associated with perinatal outcome. Importantly, the UA Doppler flow pattern can change during gestation, which has an impact on the risk of fetal death. Nevertheless, under strict fetal surveillance, the perinatal outcome of these pregnancies is favorable. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Heredabilidad de las capacidades motoras: estudio con gemelos monocigóticos y dicigóticos / Heritability of motor skills: study with monozygotic and dizygotic twins

El objetivo del estudio fue evaluar el poder relativo de contribución genética y ambiental de la variación de capacidades motoras en gemelos monocigóticos y dicigóticos. MÉTODO:participado 88 sujetos divididos en 56 monocigóticos y 32 dicigóticos de ambos sexos. Para la evaluación de la flexibilidad fue realizado el test de flexión de cadera; para la potencia de miembros inferiores fue aplicado el test contra movimiento y para la velocidad de desplazamiento, el test de carrera de 30m. Para determinar el índice de heredabilidad, utilizamos la ecuación: (h²) = (S²DZ-S²MZ)/S²DZx100. Fue utilizado tratamiento descriptivo y el test Shapiro-Wilk. Con la varianza de datos fueron calculados valores de tendencia central. Los datos fueron categorizados en percentiles de 25%. RESULTADOS: flexibilidad 16%, velocidad de desplazamiento 83% y potencia de los miembros inferiores 70%. CONCLUSIÓN: Fue evidenciado mayor heredabilidad para las variables de potencia y velocidad, y mayor influencia ambiental para la flexibilidad

The aim of the study was to assess the relative power of genetic and environmental contributions to the variation of motor skills in monozygotic and dizygotic twins. Method: For this study, participated 88 people divided in 56 monozygotic and 32 dizygotic twins of both sexes. For the assessment the flexibility, was performed hip flexion test, for assessment the lower limbpower, was applied the test against movement and the speed of movement, the 30m running test. To determine the index of heritability, was used an equation: (h ²) = (S ²MZ- S²DZ) / S²DZx100. For the statistic, was used the descriptive treatment and Shapiro-Wilk test. The variance values were calculated, through the tendency central values. Data were categorized into percentiles of 25%. RESULTS: Flexibility was 16% by heritability influence, speed of movement 83% of influence and for the lower limbs power were 70%. CONCLUSIONS: In this study was demonstrated higher heritability for the variables of lower limbs power and the speed of movement, and for the flexibility, a greater influence was linked for environmental factors

Embarazo gemelar parápago diencéfalo / Twin pregnancy parápago diencéfalo

Introducción: Los gemelos unidos son monocigóticos, monoamnióticos, monocoriales, unidos por alguna región anatómica, resultado de una división incompleta del disco embrionario que ocurre después del día 13 de la concepción, es raro...

Introduction: The conjoinet twins are monozygotic, monoamnioticos, monochorionic joined by so meanatomical region. the result of anin complete division of the embryonic disc that occut after the 13th day of conception, is rare...

Restricción selectiva del crecimiento intrauterino en la gestación gemelar monocorial: diagnóstico y manejo / Selective intrauterine growth restriction in monochorionic-diamniotic twins: diagnosis and management

La Restricción Selectiva del Crecimiento Intrauterino se produce en 10 a 19% de los gemelos monocoriónicos, y se asocia con un aumento importante de la mortalidad y la morbilidad perinatal. La evolución clínica está dada en gran parte por la presencia de anastomosis vaculares y la distribución placentaria asimétrica. Se propuso una clasificación en tres tipos según el Doppler de la arteria umbilical del gemelo más pequeño, la que sé que se correlaciona con distintos comportamientos clínicos y características de la placenta, lo que ayuda en el asesoramiento y conducta obstétrica. Los del tipo I tienen un pronóstico favorable por el resultado perinatal satisfactorio por lo que se recomienda un seguimiento cercano por ecografía y Doppler. Los de tipo II tienen un mal pronóstico y el tipo III un pronóstico intermedio e impredecible. En estos dos últimos se puede realizar un manejo expectante hasta que se observe deterioro del feto pequeño, considerando la posibilidad de la coagulación con láser o la oclusión del cordón (feticidio selectivo). Ambas conductas aparentemente aumentan las posibilidades de supervivencia del feto de peso normal.

Selective intrauterine growth restriction occurs in 10-19% of monochorionic twins, and is associated with increased mortality important and perinatal morbidity. The clinical course is given largely by the presence of placental vascular anastomosis and asymmetric distribution. It classified into three types according to the proposed Doppler umbilical artery smaller twin, the one that correlates with different clinical behaviors and characteristics of the placenta, which helps in counseling and obstetric conduct. The type I have a favorable prognosis for satisfactory perinatal outcome so closely monitored by ultrasound and Doppler is recommended. The type II has a poor prognosis and type III intermediate and unpredictable prognosis. In these last two you can make an expectant management until deterioration of the small fetus is observed, considering laser coagulation or cord occlusion (selective feticide). Both behaviors appear to increase the chances of survival of the fetus of normal weight.

Determination of twin zygosity: a comparison of DNA with various questionnaire indices.

This study examined cross-validation and test-retest reliability of questions and questionnaire indices commonly used for twin zygosity classification. Mothers of 58 monozygotic (MZ) and 52 dizygotic (DZ) same sex twin pairs were interviewed by telephone to answer questions regarding the similarity of their twins (mean age = 14.6 +/- 2.8 years). A logistic regression equation correctly classified 91% of both MZ and DZ twin pairs in our sample using 7 of the 12 zygosity questions. The internal consistency for the total questionnaire (Cronbach's alpha) was 0.88. The median two month temporal stability estimate for the individual questions was r = .56 and r = .79 for the test total. For the cross-validation, zygosity classification indices taken from 9 previous studies were applied to our sample and compared to classification according to DNA microsatellite analyses (agreement range = 44 to 100%). The accuracy of the classification indices was significantly lower than the original studies for 62% of the comparisons. If zygosity determination with DNA markers or blood group typing for all subjects is not feasible, rather than using classification indices based on other studies, an optimal classification scheme can be achieved by using a zygosity questionnaire of which the reliability and validity of the questions is established in a random subsample of the same twin cohort.

Zygosity of twins: is it time for a new terminology?

The term zygosity reflects the origin of twins--when twins are monozygotic, they are derived from a single fertilized ovum; when twins are dizygotic--the come from two fertilized ova. Zygosity assessment seemed straightforward 50 years ago. Currently, as more information and more technology becomes available, zygosity testing becomes a real problem. It is important to realize the importance of correct zygosity testing not only in the antepartum care of the pregnant mother, but more importantly--during the whole lifetime of twin individuals. This paper discusses revolving around zygosity, methods of assessment, their limitations and proposes new terminology which incorporates the recent knowledge about early human development.

Acardius acephalus. Informe de un caso y revisión de la literatura / Acardius acephalus. A case report and review of the literature

Se presenta el caso de un producto acardius acephalus gemelar de la tercera gesta, con peso de 2375 g, de término, cuyo primer gemelo se obtuvo a término, y sin malformaciones. La descripción anatómica lo incluye dentro de los productos clasificados como acárdicos amorfos, reportándose vesículas ópticas, placoda auditiva, columna vertebral incompleta, esbozos de intestino grueso, así como de tejido cerebral, duramadre y plexos coroideos. No se encontró la presencia de cavidades torácica ni abdominal. Se realizó registro, diagnóstico y clasificación del caso, con revisión de la literatura

Validation of a telephone zygosity questionnaire in twins of known zygosity.

The aim of this study was to validate a zygosity questionnaire that can be administered over the telephone. Mothers of same-sexed twins of known zygosity and chronicity between 2 and 31 years of age were interviewed on a nine-item questionnaire. From the answers one unweighted and four weighted indices were computed. As single questions, the mother's opinion and the "two peas in a pod" question differentiated best between monozygotic and dizygotic twins. One independent well-trained observer assessed the zygosity based on the questionnaire and made the correct diagnosis in 96% of the cases. A weighted index of eight similarity questions yielded an accuracy of 98%. This study shows that the zygosity of same-sexed twins more than 2 years old and without gross physical malformation can reliably be determined by a telephone questionnaire with a high accuracy.

Zygosity testing. Current status and evolving issues.

This paper reviews the current status and evolving issues in the field of zygosity testing. Monozygotic twins are seldom absolutely identical. Traditional methods of zygosity testing, mathematical ones and assessment of physical characteristics are reviewed. The proper delineation of zygosity based on placentation and chorionicity is outlined. Genetic and environmental discordance patterns are described, with a discussion of why "identical" twins are never identical preceding specific guidelines for clinical practice.

Very early and simple determination of chorionic and amniotic type in twin gestations by high-frequency transvaginal ultrasonography.

OBJECTIVE: The aim was to determine the chorionic and amniotic types in multifetal pregnancies with transvaginal ultrasonography at very early stage of gestation. STUDY DESIGN: Twenty-one spontaneous multifetal pregnancies were scanned transvaginally before 8 weeks' gestation (four of them from 4th week). The chorionic and amniotic type was determined ultrasonographically. All twin gestations had postpartum pathologic evaluation of the placenta and histologic determination of the chorionic and amniotic type. RESULTS: Ultrasonographic evaluation of the 21 pregnancies demonstrated 20 twin and 1 triplet gestation. Four of the twin pregnancies were monochorionic-diamniotic. Triplet was monochorionic-triamniotic (spontaneously aborted in 8th week of gestation). In all 20 twin pregnancies, transvaginal ultrasonography correctly predicted the chorionic and amniotic type before 8 weeks of gestation. CONCLUSION: Transvaginal ultrasonography allows a reliable, simple and rapid determination; the dichorionic twin pregnancy in 4 weeks, monochorionic in 5 weeks, and differentiation of mono- or diamniotic in 7 weeks of gestation.

Some perinatal characteristics of monozygotic twins who are dichorionic.

Zygosity testing of all multiple births allowed the identification of a subgroup of 42 monozygotic twin pairs who have dichorionic placentas, fused and separate. Perinatal outcomes of this group were compared with 110 pairs of monochorionic monozygotic twins and 148 pairs of dizygotic twins. Dichorionic monozygotic twins had the lowest incidence of preterm birth, perinatal mortality, and birth weight discordance. There was an excess of like-sexed over unlike-sexed pairs among the dizygotic twins.

Acardia: reporte de un caso y revisión de la literatura / Acardia: case one and literature review

Se presenta el caso de un feto acárdico, nacido de parto gemelar, siendo el primer caso reportado en la literatura peruana. Se describe los hallazgos de necropsia y estudio cromosómico. Se discute la etiología de esta anomalía y su incidencia en la población

Genetic variance and heritability of temperament among Chinese twin infants.

In order to examine the genetic variance and heritability of temperament among Chinese infants in Taiwan, a total of 62 pairs of same-sexed twin infants given birth in four major general teaching hospitals in Taipei City were studied. Based on placentation and 12 red blood cell antigens, 44 MZ and 18 DZ pairs were identified. Temperament was assessed at the age of six months by the Chinese edition of Carey's Temperament scale. Significant genetic variance was observed for activity level, approach or withdrawal, intensity of reaction, quality of mood, and threshold of responsiveness, with a heritability of 0.64, 0.56, 0.74, 0.39, and 0.45, respectively. There was no significant intrapair difference in temperamental characteristics between monochorionic and dichorionic MZ twins.

Evaluation of zygosity diagnosis in twin pairs below age seven by means of a mailed questionnaire.

The mothers of a consecutive series of 125 same sexed pairs of twins aged 6 months to 6 1/2 years completed a mailed questionnaire concerning the physical similarity of the twin partners. Zygosity diagnoses were first determined blindly on the basis of the answers given by the mothers, who did not know the result of the blood group test when fulfilling the questionnaire. Next, the results were compared with the zygosity determination based on examination of erythrocyte-, serum- and enzyme-groups. It turned out that a few simple questions distinguished well enough between MZ and DZ pairs, with a frequency of misclassification of 4%, leaving 5% as unclassifiable. It is concluded that twin zygosity can be estimated by a simple questionnaire with sufficient accuracy even in very young twin pairs. This has relevant implications for more extensive twin studies where the use of a wide spectrum of serological characters would imply too high expenses.