In this study we examine the hypothesis that monozygotic (MZ) twins in historical databases are less discordant for birth weight due to negative selection of severely discordant MZ twins. Furthermore, we test the hypothesis that MZ twins are less discordant for birth weight when comparing a volunteer based twin registry with a population based twin registry, due to selective registration. Data ...

BACKGROUND Chronic placental inflammation, such as villitis of unknown etiology (VUE) and chronic chorioamnionitis (CCA), is considered a placental manifestation of maternal anti-fetal rejection. The aim of this study is to investigate its frequency in twin pregnancies compared to singleton pregnancies. METHODS Three hundred twin placentas and 1,270 singleton placentas were consecutively coll...

BACKGROUND Pre-Eclampsia (PE) affects 6-31% of pregnant women with multiple gestations. There are conflicting reports on the association of PE with Chorionicity and zygosity; however, there is a lack of information on this potential association in a population of pregnant Asian Indian women. AIM To determine as to whether chorionicity and zygosity were associated with PE in a population of As...

BACKGROUND Twin pregnancy is associated with more pregnancy complications and poorer pregnancy outcome than singleton pregnancy. Hence periodic review is necessary to improve on the pregnancy outcome. OBJECTIVE To determine the incidence and compare pregnancy complications and obstetric outcomes of twin pregnancies and singleton pregnancies. MATERIALS AND METHODS The twin pregnancies (study...

PURPOSE Twin studies have demonstrated a high heritability for refractive error of up to 90%, but some family studies have suggested up to one-third of population variance is attributable to the effects of shared family environment. This large twin study aimed to explore the role of shared environment in refractive error. METHODS Refractive error was measured using autorefraction in 4602 subj...

A retrospective longitudinal study was performed to quantify foetal growth velocities in twin pregnancies and to determine the effect of variables specific to twin pregnancies on growth velocity. Foetal growth velocity standard deviation (Z) scores were calculated from serial ultrasound data using published singleton reference data for 131 consecutive sets of twins from 30 to 37 weeks' gestatio...

This study is the first report of genetic and environmental influences on birthweight using Korean twins. The sample consisted of 255 monozygotic (MZ) and 178 dizygotic (DZ) twin pairs drawn from the Seoul Twin Family Study. Intraclass twin correlations were computed for the twins' birthweights obtained from parents (typically mothers) of the twins. To estimate genetic and shared and nonshared ...

STUDY QUESTION Does the intergenerational influence on birthweight and birth length remain within female dizygotic and monozygotic twin pairs? SUMMARY ANSWER The intergenerational influence on birthweight and birth length remained within dizygotic but not within monozygotic twin pairs. WHAT IS KNOWN ALREADY Low birthweight is associated with increased morbidity and mortality in both the sho...

PURPOSE To report the frequency of adult-onset myopia in a large cohort of Caucasian twins that were assessed as part of the Genes in Myopia (GEM) twin study and to quantify the genetic contribution in adult-onset myopia using the classic twin model. METHODS All twins aged 18 years or older were invited to participate in the GEM twin study through the Australian Twin Registry (ATR). Each twin...