Unequal placental sharing and birth weight discordance in monochorionic diamniotic twins

Fick, Andrea; Feldstein, Vickie A.; Norton, Mary E.; Fyr, Christina Wassel; Caughey, Aaron B.; Machin, Geoffrey A.

doi:10.1016/j.ajog.2006.01.015

Cited by 168 publications

(119 citation statements)

References 15 publications

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“…Apart from cord entanglement, other complications such as fetal abnormalities, twin-to-twin transfusion syndromes and selective IUGR are possible reasons for the high loss rate in MCMA twins (Acosta-Rojas et al, 2007;Fick et al, 2006;Gratacós et al, 2008). The latter two complications are more likely to develop if inter-twin anastomoses are fewer and if the placental cord insertions are far apart (Denbow et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Pregnancy Outcome of Monochorionic Twins: Does Amnionicity Matter?

et al. 2011

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Objective: To compare the fetal loss rate of monochorionic (MC) twin pregnancies according to their amnionicity. Methods: A retrospective review of all MC pregnancy outcomes in a tertiary centre. Pregnancy outcomes were compared for monochorionic monoamniotic (MCMA) versus monochorionic diamniotic (MCDA) pregnancies. Results: 29 MCMA and 117 MCDA twin pregnancies were identified. The overall fetal loss rate was significantly higher in MCMA (23/52, 44.2%) compared to MCDA pregnancies (28/233, 12%, Chi squared = 30.03, p < .001). Kaplan-Meier analysis showed that fetal survival rate in MCDA twins were significantly higher than in MCMA twins (Log-rank Chi-squared = 27.9, p < .0005). Early pregnancy ultrasound identified the causes for these fetal losses in some MCMA twins. After exclusion of identifiable causes, the difference in fetal survival was not significant in the two groups (Log-rank chi-squared = 0.373, p = .54). Conclusion: The loss rate for MCMA twins is high and occurs mainly due to discordant congenital abnormality, conjoint twins or twin reversed arterial perfusion (TRAP) sequence. Although the fetal loss rate in MCDA is lower than in MCMA pregnancies, the majority of fetal loss in MCDA pregnancies cannot be predicted at the first scan at presentation. The data of this study questions the widespread policy of a difference in the scheduling of elective delivery for MCMA and MCDA twins.

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Section: Discussionmentioning

confidence: 99%

Pregnancy Outcome of Monochorionic Twins: Does Amnionicity Matter?

et al. 2011

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“…In keeping with this notion, most studies of the mechanisms underlying BW differences between MZ twins have focused on the placenta as the chief determinant of the in utero environment, linking withintwin differences in prenatal growth to inequitable access to placental tissue (35). The capacity of placental mechanisms for BW variation to also impact brain development has been established through experimental modification of effective placental transfer in animal models of placental insufficiency (1) and maternal undernutrition (36,37).…”

Section: Modeling Prenatal Environmental Influences On Brain Developmentmentioning

confidence: 99%

Prenatal growth in humans and postnatal brain maturation into late adolescence

Raznahan

Greenstein²,

Lee³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

180

179

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Prenatal life encompasses a critical phase of human brain development, but neurodevelopmental consequences of normative differences in prenatal growth among full-term pregnancies remain largely uncharted. Here, we combine the power of a withinmonozygotic twin study design with longitudinal neuroimaging methods that parse dissociable components of structural brain development between ages 3 and 30 y, to show that subtle variations of the in utero environment, as indexed by mild birth weight (BW) variation within monozygotic pairs, are accompanied by statistically significant (i) differences in postnatal intelligence quotient (IQ) and (ii) alterations of brain anatomy that persist at least into late adolescence. Greater BW within the normal range confers a sustained and generalized increase in brain volume, which in the cortical sheet, is specifically driven by altered surface area rather than cortical thickness. Surface area is maximally sensitive to BW variation within cortical regions implicated in the biology of several mental disorders, the risk for which is modified by normative BW variation. We complement this near-experimental test of prenatal environmental influences on human brain development by replicating anatomical findings in dizygotic twins and unrelated singletons. Thus, using over 1,000 brain scans, across three independent samples, we link subtle differences in prenatal growth, within ranges seen among the majority of human pregnancies, to protracted surface area alterations, that preferentially impact later-maturing associative cortices important for higher cognition. By mapping the sensitivity of postnatal human brain development to prenatal influences, our findings underline the potency of in utero life in shaping postnatal outcomes of neuroscientific and public health importance.P renatal life encompasses a foundational and universally critical phase of human brain development. Consequently, research aimed at understanding how prenatal influences play out in later life cannot only illuminate mechanisms of fundamental importance to basic developmental neuroscience, but may also have public health implications.Exquisite sensitivity of the developing brain to prenatal environmental insults has been well established through experimental animal models (1). In humans, where experimental approaches are not feasible, numerous observational studies have linked frank insults during prenatal life [as indexed by premature delivery (2); abnormally low birth weight for gestational age (3); and maternal exposure to radiation (4) or starvation (5)], to altered postnatal brain development. However, by virtue of their relative rarity, such frank prenatal insults may be less impactful at the population level than more subtle variations of the in utero environment occurring among the uncomplicated pregnancies from which most people are born (6). Evidence that subtle alterations of the prenatal environment may have meaningful consequences for postnatal development in humans can be found in large-scale epidemiolog...

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“…This parameter is based on the fact that MC twins have lower and more discordant birthweights than DC twins (Blickstein & Keith, 2004;Fick et al, 2006;Gielen et al, 2008;GonzalezQuintero et al, 2003). One would expect MZ DC twins to be the least discordant, because they are genetically identical, have their own placenta and, therefore, do not have to compete for nutrients.…”

mentioning

confidence: 99%

Can Birthweight Discordancy Within Monozygotic Twin Pairs Be Used as an Indicator of Chorionicity?

Gielen

Derom

Derom³

et al. 2009

Twin Res Hum Genet

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Both zygosity and chorionicity provide important information in twin research. The East Flanders Prospective Twin Survey (EFPTS) determines zygosity and chorionicity at birth and therefore provides a gold standard for the testing of diagnostic parameters that can be used to determine chorionicity. The aim of the present study was to investigate whether birthweight discordancy can be used as an indicator of chorionicity. The study sample consisted of 4,060 live-born twin pairs from the EFPTS. We studied MZ twins, using univariate and multivariate logistic regression analyses to calculate odds ratios (OR) and 95% confidence intervals (CI) of being MC in relation to discordancy level. Diagnostic parameters, including sensitivity and specificity, were calculated. A two-fold cross-validation was carried out and a bootstrap distribution with 10,000 samples was created to estimate the standard deviations. For discordancy levels of below 10%, 10-15%, 15-20%, 20-25% and above 25%, the ORs (95% CI) were 1.16 (0.91-1.47), 1.38 (1.05-1.80), 2.13 (1.51-3.01), 2.73 (1.73-4.29) and 2.81 (2.81-4.35) respectively. There were no gender differences. Sensitivity was 42.2% (SD 5.6%), specificity was 72.8% (SD 6.3%), positive predictive value was 72.8% (1.5%) and the negative predictive value was 39.2% (0.7%). In conclusion, although a higher discordancy level resulted in higher ORs of being an MC twin, birthweight discordancy level can only be used to some weak extent as a proxy for chorionicity, highlighting the need to assess and record chorionicity data in obstetrical units.

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Unequal placental sharing and birth weight discordance in monochorionic diamniotic twins

Cited by 168 publications

References 15 publications

Pregnancy Outcome of Monochorionic Twins: Does Amnionicity Matter?

Pregnancy Outcome of Monochorionic Twins: Does Amnionicity Matter?

Prenatal growth in humans and postnatal brain maturation into late adolescence

Can Birthweight Discordancy Within Monozygotic Twin Pairs Be Used as an Indicator of Chorionicity?

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