Why zygosity of multiple births is not always obvious: an examination of zygosity testing requests from twins or their parents.

This paper examines why parents of twins or adult twins themselves request zygosity testing. Of 405 multiples including 8 sets of triplets, the majority (93%) were monozygotic. Age of testing ranged from 0 days to 73 years. About 50% of requests came from parents or twins who were curious about, or expressed a need to be certain of, their zygosity. Other reasons included health concerns (current or future), other twins in the family, and misinformation about zygosity, frequently because of the erroneous assumption that all dichorionic twins are dizygotic. Parents of monozygotic twins may expect their twins to be 'identical' and believe their twins to be dizygotic because of minor phenotypic differences between them. Dizygotic twins like other siblings may share a phenotypic resemblance. Health professionals should be aware that zygosity of multiples may not always be obvious to parents and that accurate knowledge of zygosity may be justified.     

A Conversation with Bakhtin : On Inquiry and Dialogic Thinking

Two different traditions in psychology emphasize the study of twin-twin and mother-twin relationships. One line of research, the twin development approach, has compared parenting styles and sibling relationships in families with twin and singleton offspring. This research tradition is based on the assumption that twins, relative to singletons, may be at risk for developmental delays in motor, cognitive [1-3], linguistic [1,4,5], and social-emotional functioning [6,7] because of their increased rate of prematurity, lower birth weight [8-11], increased parenting demands that result in less interactive maternal speech [12-18], shared peer time [19], and other experiences that distinguish twins from singletons [7,8,19-21]. Although recent studies have not replicated the developmental concerns [22-26] or concerns about specific birth defects [27] that emerged from earlier studies comparing twins and singletons, there continues to be interest in the relational differences that may be present in twin and singleton families and in the need to address educational and social policies that promote twin development [28,29]. Within the framework of this approach, distinctions between twins and singletons have received more attention than distinctions between fraternal, dizygotic (DZ) and identical, monozygotic (MZ) twins.     

Expectant Parents’ Understanding of the Implications and Management of Fever in the Neonate

Objective

We estimated the extent to which Canadian expectant parents would seek medical care in a febrile neonate (age 30 days or less). We also evaluated expectant parents’ knowledge of signs and symptoms of fever in a neonate, and explored the actions Canadian expectant parents would take to optimize the health of their child.

Methods

We conducted a cross-sectional survey of a sample of expectant parents from a large urban center in Canada. We recruited participants from waiting rooms in an obstetrical ultrasound clinic located in an urban tertiary care hospital in Montreal, Canada. We asked participants nine questions about fever in neonates including if, and how, they would seek care for their neonate if they suspected he/she were febrile.

Results

Among the 355 respondents, (response rate 87%) we found that 75% of parents reported that they would take their febrile neonate for immediate medical assessment, with nearly one fifth of the sample reporting that they would not seek medical care. We found no significant associations between the choice to seek medical care and expectant parents socio-demographic characteristics.

Conclusions

Despite universal access to high quality health care in Canada, our study highlights concerning gaps in the knowledge of the care of the febrile infant in one fifth of expectant parents. Physicians and health providers should strive to provide early education to expectant parents about how to recognize signs of fever in the neonate and how best to seek medical care. This may improve neonatal health outcomes in Canada.     

Monoamniotic twins: what should be the optimal antenatal management?

Monoamniotic twinning is a rare event with an incidence of 1% of all monozygotic twins and associated with a high fetal morbidity and mortality. Confident early diagnosis is possible, but optimal management is not yet established. This article presents the experience of a single centre in managing all monoamniotic twins diagnosed during 1994-2000. Seven pairs of monoamniotic twins were identified for analysis. All were managed in accord with a unit protocol that involved early diagnosis, serial ultrasound examination and elective early delivery. In four cases, the detection of monoamnionicity was made during a first trimester nuchal scan. Discordance for structural abnormality was found in three cases where the co-twin was normal. Cord entanglement was detected antenatally in four cases. Two pairs of twins died before 20 weeks. One of these had early onset twin-twin transfusion syndrome. In five cases, the pregnancy continued beyond 20 weeks. A live birth rate of 90% and intact survival of 70% were achieved in this group. We believe that ultrasound is reliable in diagnosing monoamniotic twins and the detection of cord entanglement. Timing of elective delivery is a balance between the risks of preterm birth at a specific gestational age in an individual centre compared with the unquantifiable risks of fetal death if an expectant policy were pursued. The decision to deliver and at which gestational age should combine input from the parents, neonatologist, fetal medicine consultant and the obstetrician.     

Coital frequency and twinning

In a comparative study to enquire whether parents of twins, especially of dizygotic twins, have a higher frequency of sexual intercourse than parents of singleton infants, data on sociodemographic status, coital frequency and other variables were collected using a postal questionnaire. Parents of all twins born alive in Denmark in 1984 or 1985 were included as cases and a random sample of parents of singleton infants born in the same period were controls. No evidence of any difference in coital frequency was found between parents of twins (neither dizygotic twins nor monozygotic) and parents of singleton infants.     

Predictors of Fat Stereotypes among 9‐Year‐Old Girls and Their Parents

Objective:To assess familial links in fat stereotypes and predictors of stereotypes among girls and their parents. Research Methods and Procedures:Fat stereotypes were assessed using a questionnaire developed for this study. Participants indicated the extent to which they agreed with nine statements about thin people (e.g., thin people are smart) and the same statements about fat people (e.g., fat people are smart). Predictors of fat stereotypes that were examined include weight status (BMI; girls and parents), education (parents), income (parents), self‐investment in physical appearance (parents), maladaptive eating attitudes (girls), and parenting practices and peer interactions focused on body shape and weight loss (girls). Results:Girls and parents exhibited fat stereotypes. Fathers who were more educated and had a higher family income were more likely to endorse fat stereotypes, as were mothers and fathers with a high investment in their physical appearance. Although no associations were found between girls’ and parents’ fat stereotypes, girls were more likely to endorse fat stereotypes when interactions with parents and peers focused on body shape and weight loss. Girls were also more likely to endorse fat stereotypes when they reported higher levels of maladaptive eating attitudes. No associations were found between weight status and fat stereotypes. Discussion:Although there was no association between girls’ and parents’ fat stereotypes, girls were more likely to express negative attitudes about obesity and obese persons when parenting practices and interactions with peers promoted a lean body type, suggesting that there may be an implicit link between the lean ideal and fat stereotypes.     

Towards a Model of Contemporary Parenting: The Parenting Behaviours and Dimensions Questionnaire

The assessment of parenting has been problematic due to theoretical disagreement, concerns over generalisability, and problems with the psychometric properties of current parenting measures. The aim of this study was to develop a comprehensive, psychometrically sound self-report parenting measure for use with parents of preadolescent children, and to use this empirical scale development process to identify the core dimensions of contemporary parenting behaviour. Following item generation and parent review, 846 parents completed an online survey comprising 116 parenting items. Exploratory and confirmatory factor analyses supported a six factor parenting model, comprising Emotional Warmth, Punitive Discipline, Anxious Intrusiveness, Autonomy Support, Permissive Discipline and Democratic Discipline. This measure will allow for the comprehensive and consistent assessment of parenting in future research and practice.     

Protease inhibitor (Pi) locus,fertility and twinning

Summary In a sample of 160 Dutch twin pairs and their parents, we found that mothers of dizygotic twins had frequencies of the S and Z alleles at the protease inhibitor (Pi) locus that were 3 times higher than a control sample. Mothers of identical twins also had a higher frequency of S than controls. The S allele may thus both increase ovulation rate and enhance the success of multiple pregnancies. There was also an increased frequency of the S allele in fathers of dizygotic twins; however, this may be a secondary effect of assortative mating for family size (indicating by the number of siblings of the parents), for which a correlation of 0.2 was observed. Parents of dizygotic twins came from larger families than parents of monozygotic twins, but no effect of Pi type on family size was seen.     

Parents, ADHD and the internet

The objective of this study is to examine the potential impact of using the internet on medical consultations by analysing the attitudes, attributions, and emotional responses of parents who have been informed by specialists that their child does not have attention-deficit hyperactivity disorder (ADHD) and to examine the nature of the feedback they obtained from members of online internet support groups. Over 40,000 messages from the five most popular international internet forums discussing children with ADHD were analysed. Messages from parents who reported that they had seen at least one specialist (e.g. paediatrician, psychiatrist or psychologist) because of their concerns that their child had ADHD were identified. The children included boys and girls with an age range from 2 to 16?years. Of these, we analysed messages where the parents additionally reported that the specialist had excluded a diagnosis of ADHD. Using these criteria, 91 messages from parents who had consulted over 200 different specialists and 398 replies to these messages were identified for content analysis. The replies to concerned parents were analysed to determine whether they were offered impartial advice. A majority of the parents reported that they did not believe the specialist and were unhappy about their child not being diagnosed with ADHD. They expressed dissatisfaction with the professional's opinions and the implication that their child's conduct was caused by their poor parenting skills. Importantly, 87.6?% of the responses that these parents received, from other members of online forums, reinforced the parent's negative attitude towards the professional's judgement. It was generally suggested that the parents should not believe the expert and should seek a further opinion. The use of the internet may encourage "doctor shopping" and mistrust in health services. Medical professionals and others may need to be aware of this, and parents may need more support than is generally offered to be able to accept alternative explanations for their child's behaviour.     

Bereavement in twin relationships: an exploration of themes from a study of twinship.

The primary foci of twin research have been on twins as a biological phenomenon, on the management of medical complications of twin pregnancy and birth and on the study of individual differences and development by psychologists and geneticists for whom twins provide a powerful research tool. The twin relationship - twinship - has received less research attention, including the aspect of bereavement which may occur at any stage of life. This paper presents some findings from a qualitative study that used grounded theory methodology to explore the nature of twinship especially issues relevant to psychological counselling with twins. Fourteen participants were interviewed in-depth about their understanding and experience of twinship. Participants were selected who had a rich knowledge and experience of twinship and of therapeutic work. Segments of transcribed interviews were constantly compared to describe and elaborate frequently repeated concepts in the data. Two of the main themes of discernment, the core category of the theory of twinship, are described. These are 'defining boundaries' and 'managing ambiguity'. Aspects of these as experienced by twins are discussed in the light of current psychological theories about bereavement.     

Twins and non-twin siblings: different estimates of shared environmental influence in early childhood.

Twin studies typically indicate shared environmental influence for cognitive abilities, especially in early childhood. However, across studies, DZ twin correlations tend to be greater than non-twin sibling correlations, suggesting that twin estimates of shared environment are to some extent specific to twins. We tested this hypothesis in a sample of more than 1800 MZ and 1800 same-sex DZ pairs from the Twins Early Development Study (TEDS), a study of twins born in England and Wales in 1994 and 1995. For this analysis, we obtained comparable data from more than 130 same-sex younger siblings of the twins. Twins and their younger siblings were assessed for language, cognitive abilities and behavior problems by their parents at 2 and 3 years of age. For language and cognitive measures at both 2 and 3 years, but not for behavior problems, estimates of shared environment were more than twice as large for twins as compared to non-twin siblings. We conclude that about half of twin study estimates of shared environment for cognitive abilities in early childhood are specific to twins. Although many possibilities exist for explaining the special shared environment effect for twins, we suggest that cognitive-relevant experiences that are not shared by siblings are shared by twins because they are exactly the same age.     

The cognitive and identity development of twins at 16 years of age: a follow-up study of 32 twin pairs.

This is a follow up study of twins within the Stockholm area, including 32 families and their twins attending grade nine. The twins have been followed from birth to 16 years of age. The main purpose of this study from its inception was to assess mental and cognitive development at different ages. Another aim was to see how the twins who were born prematurely are developing during the school ages. A third aim has been to gain a deeper insight into the relationship between co-twins and the development of their identities, which is the focus of this paper. Several ability tests have been used, as well as questionnaires about interests, attitudes toward school, and leisure activities. At the 16-year follow-up, a psychological method, the Wartegg drawing test, designed to examine identity, ego strength, dependency, ambition, anxiety, willpower, creativity, empathy and coping strategies has been used. The results indicate that it is difficult for twins to develop independence and a positive identity, as they have to emancipate themselves both from their parents and from their co-twins. Some differences in identity, anxiety and ambition were observed between female and male twins, MZ and DZ twins, preterm and fullterm twins. Prematurity, sex and zygosity no longer had any relation to cognitive development at 16 years of age.     

Acoustic signalling of hunger and thermal state by nestling tree swallows

The begging displays used by altricial nestling birds to solicit care from parents include vigorous movements and loud calling. These begging signals have attracted considerable interest, mainly because their intensity seems excessive for the function of transmitting information about nestling need to parents. However, how information on need is encoded in the various components of the signal, especially its acoustic components, is poorly understood. We examined how begging calls of large and small nestling tree swallows, Tachycineta bicolor, changed during a short period of food deprivation and cooling, as a first step in determining the role that various call characteristics played in advertising nestling need. In contrast to previous studies, we examined several call variables, and related them not only to need for food but also need for warmth. When nestlings were deprived of food, their calls increased in rate and length. Large nestlings also increased the amplitude of their calls. When nestlings were cooled during food deprivation, they decreased the frequency of their calls and their call rate. The latter trend was especially evident in small nestlings. Our results suggest that begging calls carry information not only on the overall hunger level of broods, as emphasized in previous studies, but also on the size, hunger and thermal need of individual nestlings. Further tests are needed to determine whether parents use this information and whether begging calls are optimally designed to convey it. Copyright 2001 The Association for the Study of Animal Behaviour.     

Personal experiences of bereaved twins, parents of twins, and their carers.

We invited bereaved twins, parents of twins and carers to describe some of their personal experiences. We are grateful to all of them for their brave candour. We gave extra space to Kathy's story about the impacts of the loss of her own twin because it vividly illustrates the profound connections twinship can generate. Similarly we thought the cruelly long and complex saga of the life and death of Maxine's twins could help understanding of the distressing repercussions that often attend the low birth weight and prematurity that are so common amongst multiple births.     

Parental efficacy and child behavior in a community sample of children with and without attention-deficit hyperactivity disorder (ADHD)

Most studies of attention-deficit hyperactivity disorder (ADHD) youth have obtained data from the perspective of either children or parents, but not both simultaneously. The purpose of this study was to examine child and parent perspectives on parenting in a large community-based sample of children with and without ADHD. We identified children in grades 4?C6 and their parents through surveys administered to a random sample of public schools. We used multivariable logistic regression to determine independent associations between child and parent characteristics and the presence of ADHD while controlling for covariates and clustering by school. Sufficient data were achieved for 2,509 child/parent dyads. Ten percent of youths (n?=?240) had been diagnosed with ADHD. Compared with those without ADHD, those with ADHD were more commonly male (67.9 vs. 48.0?%, p?<?.001) and age 12 or over (16.3 vs. 10.3?%). After adjusting for covariates and clustering, compared to children without ADHD, children with ADHD were significantly more likely to report lower self-regulation (OR?=?0.68, 95?% CI?=?0.53, 0.88) and higher levels of rebelliousness (OR?=?2.00, 95?% CI?=?1.52, 2.69). Compared with parents whose children did not have ADHD, parents of children with ADHD rated their overall parental efficacy substantially lower (OR?=?0.23, 95?% CI?=?0.15, 0.33). However, child assessment of parenting style was similar by ADHD. Despite the internal challenges community-based youth with ADHD face, many parents of ADHD youth exhibit valuable parental skills from the perspective of their children. Feedback of this information to parents may improve parental self-efficacy, which is known to be positively associated with improved ADHD outcomes.     

Zygosity misclassification of twins at birth in Japan.

Though twinning rates have been rapidly increasing in Japan, the problem of zygosity misclassification at birth has been paid little attention. By analyzing four independent samples, the authors found that at a constant rate about 25-30% of monozygotic twins were misclassified as dizygotic twins at birth. This percentage is in very good accordance with that of monozygotic twins having dizygous placenta. Generally the obstetricians informed twins' parents about their children's zygosity. The number of placentas, as informed by obstetricians, was very strongly associated with zygosity. Concluding, even now many monozygotic twins in Japan may be misclassified as dizygotic at birth by obstetricians based solely on the number of placenta.     

What effect does classroom separation have on twins' behavior, progress at school, and reading abilities?

We investigated the effects of classroom separation on twins' behavior, progress at school, and reading abilities. This investigation was part of a longitudinal study of a nationally-representative sample of twins (the E-risk Study) who were assessed at the start of school (age 5) and followed up (age 7). We examined three groups of twins: pairs who were in the same class at both ages; pairs who were in separate classes at both ages; and pairs who were in the same class at age 5, but separated by age 7. When compared to those not separated, those separated early had significantly more teacher-rated internalizing problems and those separated later showed more internalizing problems and lower reading scores. Monozygotic (MZ) twins showed more problems as a result of separation than dizygotic (DZ) twins. No group differences emerged for externalizing problems, ADHD or prosocial behaviors. The implications of the findings for parents and teachers of twins, and for school practices about separating twins, are discussed.     

Parenting stress and affective symptoms in parents of autistic children

We examined parenting stress and mental health status in parents of autistic children and assessed factors associated with such stress. Participants were parents of 188 autistic children diagnosed with DSM-IV criteria and parents of 144 normally developing children. Parents of autistic children reported higher levels of stress, depression, and anxiety than parents of normally developing children. Mothers of autistic children had a higher risk of depression and anxiety than that did parents of normally developing children. Mothers compared to fathers of autistic children were more vulnerable to depression. Age, behavior problems of autistic children, and mothers' anxiety were significantly associated with parenting stress.