Twin weight discordance and maternal weight gain in twin pregnancies

Objective: To evaluate the association between twin weight discordance and maternal weight change during the gestational period. Method: One hundred forty‐seven twin pregnancies (Group A: < 25%, Group B: ≥ 25% birth weight discordance) were analyzed using Student’s t‐test, χ2‐test, and two‐way ANOVA at three gestational intervals: before 18 weeks, 18 to 28 weeks, and 28 weeks to birth. Result: There was no statistically significant difference between the two groups involving maternal age, parity, duration of pregnancy, height, pregravid weight, and conception method. Group A showed a pattern of constantly increasing maternal weight without a significant change in the twin weight discordance throughout gestation. However, Group B showed a fluctuation in maternal BMI with remarkably elevated twin weight discordance at 28 weeks to birth. Conclusion: The results suggest that in twin pregnancies constant maternal weight gain throughout gestation is important for maintaining a twin weight discordance of less than 25%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135432/1/ijgo176.pd

Birth weight discordance in spontaneous versus induced twins: impact on perinatal outcome

Purpose: To compare the rate of birth weight discordance and perinatal outcome of twin pregnancies after assisted reproduction with that of spontaneous twins. Method: A total of 12,920 deliveries were analyzed retrospectively. Seventy-five twin pregnancies after ART were compared to the 94 spontaneous counterparts. Birth weight discordance was defined as a difference of 20% or more. Results: Discordance rate was elevated (25.3% vs. 17.0%) among ART twins. SGA was increased and NICU admission was more frequent in discordant group. Unlike-sexed twins were more prevalent (73.7% vs. 37.5%) among discordants after ART. Conclusions: ART can increase discordance rate which can elevate perinatal risk

Birth status and twin birth weight discordance

Abstract Objectives: The aim of the research was to estimate the influence of birth weight discordance on birth status of twins. Material and methods: Material of the research consisted of 560 foetuses derived from successful twin pregnancies. In the analysis the following factors were taken into consideration: birth status, gasometry, and birth weight discordance. Results: The degree of birth weight discordance under 10% was noted in 50% of twin pregnancies (n=140), discordance of 10%-20% was observed in 30.7% (n=86), and >20 % - in 19,3% (n=54). Conclusions: Birth weight discordance is an important risk factor for fetal and neonatal morbidity which is higher in smaller twins than in larger ones. Along with the degree of birth weight discordance, an increased risk of neonatal complications was observed

Discordance of prenatal and neonatal brain development in twins

pre-printBackground: Discordance of birth weight has been observed in twin pairs, though little is known about prenatal and early neonatal discordance of head and brain size, and the role that zygosity and chorionicity play in discordances of early brain development in twins. Aims: To compare prenatal and neonatal discordances of head size in monozygotic - monochorionic (MZ-MC), monozygotic-dichorionic (MZ-DC), and same-sex dizygoticdichorionic twin pairs (DZ-DC). Study Design: Subjects prospectively had ultrasounds at 22 and 32 weeks gestational age, and magnetic resonance imaging (MRI) of the brain MRI after birth. Subjects: 88 twin pairs recruited from two university hospital prenatal diagnostic clinics; 22 MZ-MC, 17 MZ-DC, and 49 same sex DZ-DC pairs. Outcome measures: Discordance of head circumference (HC) and weight at 22 weeks, 32 weeks and birth, as well as intracranial volume (ICV) on neonatal MRI. Results: There were no group differences in discordance of head circumference and weight on the 22 or 32 week ultrasounds, or at birth. MZ-MC twins tended to have numerically greater discordances of HC and weight. There was a significant group difference in ICV on neonatal MRI (ANOVA, p = 0.0143), with DZ-DC twins having significantly greater discordance than MZ-MC (p = 0.028) or MZ-DC (p = 0.0131) twins. Conclusions: This study indicates that zygosity and chorionicity do not contribute to significant discordances of head size in late prenatal development. DZ twins do have significantly greater discordances of ICV on neonatal MRI, suggesting a relatively greater genetic influence on brain growth in the first weeks after birth

Intrauterine growth pattern and birthweight discordance in twin pregnancies: a retrospective study

Background: Twins, compared to singletons, have an increased risk of perinatal mortality and morbidity, due mainly to a higher prevalence of preterm birth and low birthweight. Intrauterine growth restriction (IUGR) is also common and can affect one or both fetuses. In some cases, however, one twin is much smaller than the other (growth discordance). Usually, high birthweight discordance is associated with increased perinatal morbidity. The aim of this study is to describe the epidemiological features of a population of twins at birth, with particular reference to the interpretation and clinical effects of birthweight discordance. Methods: We evaluated retrospectively the clinical features of 70 infants born from twin pregnancies and assessed birthweight discordance in 31 pregnancies where both twins were followed at our institution. Discordance was treated both as a continuous and a categorical variable, using a cutoff of 18%. Possible relationships between birthweight discordance and other variables, such as maternal age, gestational age, birthweight percentile, number of SGA newborns in the pair, Hematocrit (Ht) discordance and neonatal anemia, prevalence of malformations, neonatal morbidity and death, were analyzed. Results: In our cohort birthweight percentile decreased slightly with increasing gestational age. Birthweight discordance, on the contrary, increased slightly with the increase of gestational age. A high discordance is associated to the presence of one SGA twin, with the other AGA or LGA. In our population, all 6 pregnancies in which discordance exceeded 18% belonged to this category (one SGA twin). Ht discordance at birth is associated to the presence of neonatal anemia in a twin, but it is not significantly related to weight discordance. Finally, in our case history, weight discordance is not associated in any way with the prevalence of malformations, morbidity and mortality. Conclusions: Birthweight discordance is an important indicator of complications that act asymmetrically on the two fetuses, affecting intrauterine growth in one of them, and usually determining the birth of a SGA infant. Our case history shows a significant statistical association between pair discordance and IUGR in one of the twins, but we could not demonstrate any relationship between discordance and the prevalence of malformations, morbidity and mortality

Significance of placental cord insertion site in twin pregnancy

Objective To investigate the association between abnormal cord insertion and the development of twin‐specific complications, including birth‐weight discordance, selective fetal growth restriction (sFGR) and twin‐to‐twin transfusion syndrome (TTTS). Methods This was a single center retrospective cohort study of twin pregnancies. Abnormal cord insertion was defined as either marginal (umbilical cord attachment site less than 2 cm to the nearest margin of the placental disc) or velamentous (cord attached to the membrane before reaching the placental disc with clear evidence of vessels traversing the membranes to connect with the placental disc), as described in placental pathology reports. Twins with major structural or chromosomal abnormalities and monochorionic monoamniotic twins were not included in the study. Information on the pregnancies, ultrasound findings, prenatal investigations and interventions was obtained from the electronic ultrasound database, while data on placental histopathological findings, pregnancy outcome, mode of delivery, birth weight, gestational age at delivery and admission to the neonatal intensive care unit were obtained from maternity records. Categorical variables were compared using the chi‐square or Fisher's exact test, while continuous variables were compared using the Student's t‐test, ANOVA for multiple comparisons and the Kruskal–Wallis test. Results Of the 497 twin pregnancies included in the analysis, 351 (70.6%) were dichorionic and 146 (29.4%) were monochorionic. The incidence of birth‐weight discordance of 25% or more was significantly higher in pregnancies with velamentous and those with marginal cord insertions compared to those with normal cord insertion (24.0%, 15.3% vs 7.6%, P < 0.001 and P = 0.020, respectively). In pregnancies with birth‐weight discordance of 25% or more, the smaller twins had significantly higher prevalence of velamentous (13.8%) and marginal (34.2%) cord insertions compared with the larger twins (1.8% and 18.5%, respectively, P < 0.001). The smaller twins of the monochorionic diamniotic pregnancies showed an even higher prevalence of velamentous (29.5%) and marginal (40.9%) cord insertions compared with the larger twins (2.3% and 31.5%, respectively, P < 0.001). Compared with the normal cord insertion group, only velamentous insertion was associated significantly with the risk of sFGR (odds ratio (OR), 9.24 (95% CI, 2.05–58.84), P < 0.001) and birth‐weight discordance of 20% or more (OR, 4.34 (95% CI, 1.36–14.61), P = 0.007) and 25% or more (OR, 6.81 (95% CI, 1.67–34.12), P = 0.003) in monochorionic twin pregnancies. There was no significant association between velamentous cord insertion and TTTS (P = 0.591), or between marginal cord insertion and the development of sFGR (P = 0.233), birth‐weight discordance of 25% or more (P = 0.114) or TTTS (P = 0.487). Subgroup analysis of dichorionic twins showed that abnormal cord insertion was not associated with the risk of birth‐weight discordance (P = 0.999), sFGR (P = 0.308), composite neonatal adverse outcome (P = 0.637) or intrauterine death (P = 0.349). Conclusion Monochorionic twins with velamentous cord insertion are at increased risk of birth‐weight discordance and sFGR. Sonographic delineation of placental cord insertion could be of value in the antenatal stratification of twin pregnancies. Prospective studies are required to assess the value and predictive accuracy of this potential screening marker

Birth weight in a large series of triplets

Background: Triplets are often born premature and with a low birth weight. Because the incidence of triplet births is rare, there are relatively few studies describing triplet birth weight characteristics. Earlier studies are often characterized by small sample sizes and lack information on important background variables such as zygosity. The objective of this study is to examine factors associated with birth weight in a large, population-based sample of triplets registered with the Netherlands Twin Register (NTR).Methods: In a sample of 1230 triplets from 410 families, the effects of assisted reproductive techniques, zygosity, birth order, gestational age, sex, maternal smoking and alcohol consumption during pregnancy on birth weight were assessed. The resemblance among triplets for birth weight was estimated as a function of zygosity. Birth weight discordance within families was studied by the pair-wise difference between triplets, expressed as a percentage of the birth weight of the heaviest child. We compare data from triplets registered with the NTR with data from population records, which include live births, stillbirths and children that have deceased within days after birth.Results: There was no effect of assisted reproductive techniques on triplet birth weight. At gestational age 24 to 40 weeks triplets gained on average 130 grams per week; boys weighed 110 grams more than girls and triplets of smoking mothers weighted 104 grams less than children of non-smoking mothers. Monozygotic triplets had lower birth weights than di- and trizygotic triplets and birth weight discordance was smaller in monozygotic triplets than in di- and trizygotic triplets. The correlation in birth weight among monozygotic and dizygotic triplets was 0.42 and 0.32, respectively. In nearly two-thirds of the families, the heaviest and the lightest triplet had a birth weight discordance over 15%. The NTR sample is representative for the Dutch triplet population that is still alive 28 days after birth.Conclusion: Birth weight is an important determinant of childhood development. Triplet status, gestational age, sex, zygosity and maternal smoking affect birth weight. The combined effects amount to a difference of 364 grams between monozygotic girl triplets of smoking mothers compared to dizygotic boy triplets of non-smoking mothers of the same gestational age. Birth weight in triplets is also influenced by genetic factors, as indicated by a larger correlation in monozygotic than in di- and trizygotic triplets

Neonatal DNA methylation profile in human twins is specified by a complex interplay between intrauterine environmental and genetic factors, subject to tissue-specific influence

Comparison between groups of monozygotic (MZ) and dizygotic (DZ) twins enables an estimation of the relative contribution of genetic and shared and nonshared environmental factors to phenotypic variability. Using DNA methylation profiling of ∼20,000 CpG sites as a phenotype, we have examined discordance levels in three neonatal tissues from 22 MZ and 12 DZ twin pairs. MZ twins exhibit a wide range of within-pair differences at birth, but show discordance levels generally lower than DZ pairs. Within-pair methylation discordance was lowest in CpG islands in all twins and increased as a function of distance from islands. Variance component decomposition analysis of DNA methylation in MZ and DZ pairs revealed a low mean heritability across all tissues, although a wide range of heritabilities was detected for specific genomic CpG sites. The largest component of variation was attributed to the combined effects of nonshared intrauterine environment and stochastic factors. Regression analysis of methylation on birth weight revealed a general association between methylation of genes involved in metabolism and biosynthesis, providing further support for epigenetic change in the previously described link between low birth weight and increasing risk for cardiovascular, metabolic, and other complex diseases. Finally, comparison of our data with that of several older twins revealed little evidence for genome-wide epigenetic drift with increasing age. This is the first study to analyze DNA methylation on a genome scale in twins at birth, further highlighting the importance of the intrauterine environment on shaping the neonatal epigenome

Neurocognitive outcome of monochorionic twins with different birth weights

M.D.Background: Although the long term effect of intrauterine growth restriction has been assessed in a number of singleton studies, they all suffer from multiple confounding effects. A model that utilises monozygotic twins may markedly reduce the effect of confounders as monochorionic twins share the same gestational age length, family background, gender and genetic influences on growth and cognition. Comparison of monochorionic twins with birth weight discordance of 20% or more could be used as a model of in utero growth constraint. This model will still involve certain limitations and assumptions nevertheless; we used this to determine the level of cognitive function of in-utero growth discordant monochorionic twins in later childhood along with any differences in auxology and behavioural problems. Methods: This was a retrospective cohort study. Eligible twins were identified from the Northern Survey of Twins and Multiple Pregnancies register. Cognitive function was assessed by a single observer using the British Ability Scales 2 to measure the general conceptual ability. Strength and Difficulties Questionnaire was used to identify behavioral problems. Height, weight, mid arm circumference, waist measurement and head circumference were also collected. Generalised estimating equations were used to determine the effect of birth weight on general conceptual ability scores. Statistical analyses were performed using SPSS v19. Results: Between 2000 and 2004, a total of 51 twin pairs were assessed (n=23 female) with mean birth weight discordance 664gm and mean gestational age 34.7 weeks. The mean difference in the general conceptual ability score between the heavier and lighter twins was 3 points. Significant association between within pair differences in birth weight and general conceptual ability scores was found. Increasing birth weight discordance was not associated with a decrease of general conceptual ability scores. The differences in the size seen at birth between the twins were still detectable at the age of 5-8 years. There was a trend to increased prevalence of behavioural problems in the lighter twin compared to the heavier twin as reported by both teachers and parents but this result was not statistically significant. Conclusions: The smaller twin of a monochorionic growth discrepant pair was statistically significantly more likely to have a lower cognitive score compared to their co-twin at 5-8 years of age. This suggests that growth restriction in-utero is associated with lower cognitive scores in later childhood