The association between maternal and foetal factors with birth weight discordance in twins from Yucatan, Mexico.

Birth weight discordance (BWD) is not an uncommon event in twin pregnancies and can be associated with maternal and newborn characteristics. We aimed to analyse the association between maternal sociodemographic and newborn characteristics with BWD in twin infants born in Yucatan, Mexico, during 2008-2017 (n = 2091 pairs). BWD was calculated as the percentage of birth weight of the heavier twin. We defined three categories of BWD: concordant twins: <15%, mild-discordant: 15-24%, and severe discordant: ≥25%. A multinomial logistic regression model was used to analyse the association between maternal sociodemographic and newborn characteristics with BWD. Seventy-four percent (n = 1547) of twin pairs were classified as concordant, 17% (n = 356) met the criteria for mild-discordance and 9% (n = 188) for severe discordance. The odds for mild-discordance were significantly lower for mothers with medium level of education and in the highest quartile of total twin birth weight (TBW). Opposite-sex twin pairs showed increased odds for mild-discordance compared with same-sex pairs. The odds for severe discordance increased as mothers were in older age groups and decreased as TBW increased. Our rates of BWD are similar to those reported in populations from wealthier countries and maternal age and education, infants' sex, and TBW are associated with BWD.

Perinatal outcomes in twin pregnancies complicated by maternal morbidity: evidence from the WHO Multicountry Survey on Maternal and Newborn Health.

BACKGROUND: Twin pregnancy was associated with significantly higher rates of adverse neonatal and perinatal outcomes, especially for the second twin. In addition, the maternal complications (potentially life-threatening conditions-PLTC, maternal near miss-MNM, and maternal mortality-MM) are directly related to twin pregnancy and independently associated with adverse perinatal outcome. The objective of the preset study is to evaluate perinatal outcomes associated with twin pregnancies, stratified by severe maternal morbidity and order of birth. METHODS: Secondary analysis of the WHO Multicountry Survey on Maternal and Newborn Health (WHOMCS), a cross-sectional study implemented in 29 countries. Data from 8568 twin deliveries were compared with 308,127 singleton deliveries. The occurrence of adverse perinatal outcomes and maternal complications were assessed. Factors independently associated with adverse perinatal outcomes were reported with adjusted PR (Prevalence Ratio) and 95%CI. RESULTS: The occurrence of severe maternal morbidity and maternal death was significantly higher among twin compared to singleton pregnancies in all regions. Twin deliveries were associated with higher rates of preterm delivery (37.1%), Apgar scores less than 7 at 5th minute (7.8 and 10.1% respectively for first and second twins), low birth weight (53.2% for the first and 61.1% for the second twin), stillbirth (3.6% for the first and 5.7% for the second twin), early neonatal death (3.5% for the first and 5.2% for the second twin), admission to NICU (23.6% for the first and 29.3% for the second twin) and any adverse perinatal outcomes (67% for the first twin and 72.3% for the second). Outcomes were consistently worse for the second twin across all outcomes. Poisson multiple regression analysis identified several factors independently associated with an adverse perinatal outcome, including both maternal complications and twin pregnancy. CONCLUSION: Twin pregnancy is significantly associated with severe maternal morbidity and with worse perinatal outcomes, especially for the second twin.

Twin Peaks: A spatial and temporal study of twinning rates in Brazil.

Twin births are an important public health issue due to health complications for both mother and children. While it is known that contemporary factors have drastically changed the epidemiology of twins in certain developed countries, in Brazil, relevant data are still scarce. Thus, we carried out a population-based study of live births in spatial and temporal dimensions using data from Brazil's Live Birth Information System, which covers the entire country. Over 41 million births registered between 2001 and 2014 were classified as singleton, twin or multiple. Twinning rates (TR) averaged 9.41 per 1,000 for the study period and a first-order autoregressive model of time-series analysis revealed a global upward trend over time; however, there were important regional differences. In fact, a Cluster and Outlier Analysis (Anselin Local Moran's I) was performed and identified clusters of high TR in an area stretching from the south of Brazil's Northeast Region to the South Region (Global Moran Index = 0.062, P < 0.001). Spearman's correlation coefficient and a Wilcoxon matched pairs test revealed a positive association between Human Development Index (HDI) and TRs in different scenarios, suggesting that the HDI might be an important indicator of childbearing age and assisted reproduction techniques in Brazil. Furthermore, there was a sharp increase of 26.42% in TR in women aged 45 and over during study period. The upward temporal trend in TRs is in line with recent observations from other countries, while the spatial analysis has revealed two very different realities within the same country. Our approach to TR using HDI as a proxy for underlying socioeconomic changes can be applied to other developing countries with regional inequalities resembling those found in Brazil.

Breastfeeding Twins: Factors Related to Weaning.

BACKGROUND: Many factors may influence a woman's decision to start and maintain breastfeeding. Research aim: This study aimed to investigate the factors associated with breastfeeding cessation in twin infants during the first 6 months after birth and to describe the main reasons for weaning cited by mothers of twins. METHODS: This is a secondary data analysis of a prospective randomized trial conducted in Brazil. Data were obtained through longitudinal quantitative and qualitative self-reported interviews. One hundred twenty-eight women pregnant with twins and their 256 infants were followed for up to approximately 6 months, during which time breastfeeding data were obtained through face-to-face interviews at three different points after birth: 30 to 40 days (Time 1), 90 days (Time 2), and 180 days (Time 3). The association between weaning and the investigated factors was examined using survival analysis methodologies. RESULTS: Nonexclusive breastfeeding ( p = .004, Cox proportional hazards regression model), a lack of support during the lactation period ( p = .001), difficulty breastfeeding ( p = .003), a breastfeeding duration shorter than 12 months in a previous pregnancy ( p = .001), and infants' birth weight less than 2,300 g ( p < .001) were the factors associated with breastfeeding cessation. The main reasons for weaning cited by mothers of twins were insufficient human milk supply, infants' behavior, and returning to work. CONCLUSION: We have identified the factors associated with weaning in twin infants during the first 180 days of life. This knowledge can help improve strategies to increase breastfeeding rates in twins.

Racial Inequality in Education in Brazil: A Twins Fixed-Effects Approach.

Racial disparities in education in Brazil (and elsewhere) are well documented. Because this research typically examines educational variation between individuals in different families, however, it cannot disentangle whether racial differences in education are due to racial discrimination or to structural differences in unobserved neighborhood and family characteristics. To address this common data limitation, we use an innovative within-family twin approach that takes advantage of the large sample of Brazilian adolescent twins classified as different races in the 1982 and 1987-2009 Pesquisa Nacional por Amostra de Domicílios. We first examine the contexts within which adolescent twins in the same family are labeled as different races to determine the characteristics of families crossing racial boundaries. Then, as a way to hold constant shared unobserved and observed neighborhood and family characteristics, we use twins fixed-effects models to assess whether racial disparities in education exist between twins and whether such disparities vary by gender. We find that even under this stringent test of racial inequality, the nonwhite educational disadvantage persists and is especially pronounced for nonwhite adolescent boys.

I. 'Street of twins': multiple births in Cuba II. The Cuban twin registry: an update / twin research reports: cord entanglement; heritability of clubfoot; school separation / twins and twin researchers in the news: reunited at seventy-eight; basketball duo dissolved; delivered holding hands; the better brew; award winners.

I was part of a people-to-people tour of Havana, Cuba during the first week in April 2014. Among the many highlights of that adventure were an informal meeting with Dr Beatriz Marcheco-Teruel, from Cuba's National Center for Medical Genetics, and a visit to the famous 'Street of Twins'. A fortuitous meeting with parents of twins in the fishing town of Jaimanitas was also an extraordinary event. The Cuban experience is followed by summaries of recent twin research, covering umbilical cord entanglement, the heritability of clubfoot and school separation policies for twins. Media reports include twins reunited at age 78, the future of UCLA's twin basketball players, MZ twins born holding hands, a twin conflict over beer and a pair of American Psychological Association honors for Drs Nancy L. Segal and Thomas J. Bouchard, Jr.

Celiac disease and dermatitis herpetiformis in Brazilian twins: a long-term follow-up and screening of their relatives.

OBJECTIVES: To investigate three pairs of twins with celiac disease (CD) concerning clinical presentation, diagnostic procedures, and long-follow-up, besides screening CD in their first-degree relatives. PATIENTS/METHODS: CD was diagnosed in childhood by endoscopic duodenal biopsy in two monozygotic (MZ) female pairs (A1 and A2, B1 and B2) and one dizygotic (DZ) pair, in which the male (C1) had CD and the female (C2) was negative. The patients had periodic evaluations after a gluten-free diet (GFD) for 16 to 21 years. Nine first-degree relatives were screened by serological tests and when positive, referred for intestinal biopsies. RESULTS: At diagnosis, all CD patients had the classic presentation. A1/A2: scalloped duodenal mucosa with atrophic areas, Marsh III-b, after 16 years of GFD was antiendomysium antibody (EmA) negative, normal mucosa. B1/B2 at diagnosis: mucosal atrophy, Marsh III-b, after 21 years was EmA negative, decreased folds. Patient C1: decreased folds, Marsh III-b, after 16 years was EmA positive, decreased folds, admitted to gluten ingestion. A1, A2, and B1 presented dermatitis herpetiformis. The father of A1/A2 and the mother of C1/C2 were celiac. CONCLUSIONS: The long-term follow-up of the patients allowed some observations such as the concordance for CD in MZ twins, both in relation to the time of onset and the severity of the disease. Also, the findings of serological, endoscopic, and histological analyses were similar. Dermatitis herpetiformis was present in patients with CD, with partial concordance in MZ twins.

The changing impact of family size on adolescents' schooling: assessing the exogenous variation in fertility using twins in Brazil.

Researchers have long been interested in the influence of family size on children's educational outcomes. Simply put, theories have suggested that resources are diluted within families that have more children. Although the empirical literature on developed countries has generally confirmed the theoretical prediction that family size is negatively related to children's education, studies focusing on developing societies have reported heterogeneity in this association. Recent studies addressing the endogeneity between family size and children's education have also cast doubt on the homogeneity of the negative role of family size on children's education. The goal of this study is to examine the causal effect of family size on children's education in Brazil over a 30-year period marked by important social and demographic change, and across extremely different regions within the country. We implement a twin birth instrumental variable approach to the nationally representative 1977-2009 PNAD data. Our results suggest an effect of family size on education that is not uniform throughout a period of significant social, economic, and demographic change. Rather, the causal effect of family size on adolescents' schooling resembles a gradient that ranges from positive to no effect, trending to negative.

Influence of socioeconomic levels on birthweight of twins and singletons.

This study aimed to compare birthweight distribution of twins and singletons from three different socioeconomic level hospitals and evaluate the possible contribution of assisted reproduction technologies (ART). Data for twins and singletons were collected in the 1990s from hospitals A (370 twins, 370 singletons), B (306 twins, 306 singletons), and C (562 twins, 562 singletons). Only hospitals B and C have ART procedures. Gestational age was significantly lower in hospital C for singletons and twins. Birthweight for singletons was lower at hospital A (p <.005 for hospital B and p =.000 for hospital C); however, birthweight for twins was lower for hospitals A and C compared to hospital B (p =.000 for both comparisons). There were no differences between the mean birthweight for singletons and twins either to primigravidae or multigravidae in hospital A; nevertheless, for B and C the mean birthweight of twins was significantly lower in primigravidae than in multigravidae (p =.029 and p =.006, respectively). Considering twins up to 37-weeks of gestational age, hospital C showed the highest percentage of twin births (73.3%). These data suggest that the use of ART accounts for a disproportionate number of low birthweight and/or premature infants in primigravidae of higher socioeconomic level.

Factor and latent class analysis of DSM-IVADHD symptoms in a school sample of Brazilian adolescents.

OBJECTIVE: To evaluate the validity of the multidimensional construct proposed by DSM-IV for the diagnosis of attention-deficit/hyperactivity disorder (ADHD) in a school sample of young Brazilian adolescents. METHOD: An instrument including all 18 DSM-IVADHD symptoms was administered to 1,013 students aged 12 to 14 years at 64 state schools by trained research assistants. Each symptom was rated on a Likert scale with five levels of severity (never, almost never, sometimes, frequently, and always). RESULTS: Using an exploratory factor analytic approach (principal components analysis), two factors were extracted. Factor I (hyperactivity-impulsivity) comprised eight DSM-IV hyperactive-impulsive symptoms with loadings > or =0.40. Factor II (inattention) included also eight DSM-IV symptoms of inattention. The two factors explained 34% of the total variance and had an interfactor correlation of 0.45. Latent class analysis demonstrated similar classes in males and females, but class structures were markedly different from previous analyses of parent report data. CONCLUSION: The findings support the appropriateness of the multidimensional construct introduced by DSM-IV in the diagnosis of ADHD in a different culture but emphasize the possible impact of different reporters on the results of structural model-testing.

Biological and social traits associated with twinning among Caucasoids and Negroids

Os prontuários das mäes de gêmeos causasóides (589) e negróides (142) nascidos entre 1984 e 1993 e de um grupo controle de mäes de crianças nascidas de parto único (1267 caucasóides e 248 negróides) na maior maternidade de Campinas, SP, Brasil (Maternidade de Campinas) foram investigados para a análise das seguintes informaçöes: categoria da internaçäo hospitalar (clínica particular, INSS e indigentes), estado civil, idade materna, ocorrência de trabalho de parto, tipo de parto, paridade (partos anteriores), abortamentos espontâneos anteriores ao parto, idade gestacional e peso e estatura dos gêmeos e dos nascituros únicos. As principais conclusöes foram as seguintes: 1) as mäes caucasóides usufruiram, em maior proporçäo, de internaçäo hospitalar de categoria mais alta, mas a gemelaridade näo mostrou associaçäo com a classe social das parturientes; 2) a proporçäo de mulheres casadas entre as mäes caucasóides foi maior do que entre as negróides, e as mäes caucasóides de gêmeos incluíram maior proporçäo de mulheres casadas do que as que tiveram parto único; 3) näo se constatou diferença entre caucasóides e negróides quanto a idade média materna, ocorrência de trabalho de parto, tipo de parto, taxa de abortos espontâneos anteriores e idade gestacional; 4) quando comparadas as mäes que tiveram parto único, as mäes de gêmeos foram, em média, dois anos mais velhas, entraram menos freqüentemente em trabalho de parto, foram submetidas mais freqüentemente à cirurgia cesariana e tiveram maior taxa de abortos espontâneos, enquanto que os gêmeos tiveram menor idade média gestacional (três semanas) que os nascidos de parto único; 5) as mulheres caucasóides tiveram menor paridade que as negróides e as mäes de gêmeos maior paridade que as de partos únicos; 6) os gêmeos mostraram peso médio e estatura média menor que os nascidos de parto único, os recém-nascidos do sexo masculino mostraram peso levemente superior aos do sexo feminino, sendo os negróides mais leves e menores do que os caucasóides ao nascimento.

Twinning trend in Escazú, Costa Rica, 1851-1901.

The cross-cultural study of secular trends in twinning has been of interest to students of human biology. Although recent vital statistics are likely to be more reliable, older vital records allow a long-term study of twinning trends and of the effect of epidemics on twin incidence. Here, I report the results of an investigation of the secular trend of twin maternities from 1851 to 1901 in Escazú, Costa Rica. The research also investigates whether epidemics affected twin incidence in a consistent manner. Because the church records did not state the mother's age, it was not possible to standardize the raw twinning rate for maternal age. Thus the moving averages of the raw rates for every 33 years (the average length of a generation) were computed to minimize the effect of changing average maternal age on twin incidence. No consistent response to epidemics is apparent in the twinning rates. However, both the raw twinning rates and their moving averages indicate that the frequency of twinning decreased in Escazú during the second part of the nineteenth century. A decline in the twinning rate in other populations is usually attributed to environmental changes caused by the process of industrialization. However, the decline in the twin maternity incidence in Escazú could not be the result of such an environment because the population was rural and nonindustrialized. This study indicates that a decline in twin maternities may result from more diverse causes than was previously thought.

Investigation on seasonality of twin births in Brazil.

The hypothesis of seasonality of twin births was investigated in two important maternity hospitals in the State of São Paulo, Brazil. The study included 1,386 twin births that occurred among 154,699 deliveries from 1984 to 1993. No evidence of seasonality has been detected either for the twin birth rate considered as a whole or for dizygotic twinning rate. The distributions of these rates fitted well sinusoidal regression curves but the cyclic trend did not correspond to any specific season.

Study on possible increase in twinning rate at a small village in south Brazil.

A high frequency of twin births has been observed in Linha São Pedro, a small settlement which belongs to the city of Cãndido Godói, located 524 km Northwest from Porto Alegre, Rio Grande do Sul, Brazil, in an ethnically homogeneous population of German descent restricted to a small geographic region. From 1990 to 1994, the proportion of twin births in Linha São Pedro was 10%, significantly higher than the 1.8% rate for the state of Rio Grande do Sul as a whole. Genealogical analysis showed a high recurrence of multiple births within families, as well as a high level of inbreeding in the community. Zygosity data indicated that 9 of the 17 pairs of twins studied (53%) were dizygotic. No external environmental factors were detected that could be influencing the appearance of this characteristic. This preliminary investigation confirmed the presumed existence of a high twinning rate in the community. The high familial recurrence and the high inbreeding rate suggests the presence of genetic twinning factors. Complementary studies of twins that have yet to be evaluated and the search for additional risk factors, as well as linkage studies, should contribute to a further understanding of the biological factors related to twin births in the human species.

Maternal and neonatal variables in twins: an epidemiological approach.

Population studies on human twinning are scarce in Argentina. In order to analyze frequencies and certain maternal and neonatal variables related to twin births, we studied a series of 69.678 consecutive newborns with 500 g of weight and over, which occurred at a public hospital in the province Buenos Aires, during 14 years (1982-1995). The frequency of twin births (10 per 1000 deliveries) and sex ratio were similar to other studies reported in Caucasian population. Maternal age and order of gravity/parity were positively correlated with twinning rates, more markedly so in dissimilar sex-pairs. Stillbirths and neonatal deaths were more frequent in twins than in singletons, but less frequent when comparing groups of same weight. Congenital malformations were not found to be significantly more frequent in twins than in the total newborn population. However, their occurrence, predominantly in like-sexed pairs and the concordance for defect type in doubly affected same-sex pairs, suggests that monozygotic twinning carries an increased risk for malformation.

Perinatal outcomes of a large cohort of extremely low gestational age infants (twenty-three to twenty-eight completed weeks of gestation).

OBJECTIVES: To determine gestational age (GA)-specific mortality rates; the effects of GA, birth weight, sex, and multiple gestation on mortality rates; short-term morbidity for infants born at 23 to 28 weeks GA; and impairment rates at a corrected chronologic age of 18 months for those born at 23 to 25 weeks GA. METHODS: A data base analysis was performed with a linked obstetric and a neonatal database. GA was determined by obstetric data and confirmed by early ultrasonography (available in 88%) on all births < 30 weeks GA at British Columbia's tertiary perinatal center from 1983 to 1989. RESULTS: Of 1024 births occurring between 23 and 28 weeks GA, 911 were live born. The mortality rate decreased with increasing GA: 84% at 23 weeks; 57% at 24 weeks; 45% at 25 weeks; 37% at 26 weeks; 23% at 27 weeks; and 13% at 28 weeks GA. For each GA, mortality rate versus birth weight plots showed a decreasing mortality rate with increasing birth weight, except for infants who were large for GA. Male infants had a higher mortality rate than female infants (odds ratio, 1.8; confidence interval, 1.4 to 2.5). Twins fared worse than singletons with a decreasing effect from 24 weeks GA (odds ratio, 10.3) to no effect at 28 weeks GA. The median number of days supported by mechanical ventilation and the length of stay in the neonatal intensive care unit decreased markedly with increasing GA. Eighteen-month outcome of survivors between 23 and 25 weeks GA with 93% follow-up rate revealed an overall impairment rate of 36%, but 6 of the 9 surviving 23-week infants had major impairments. CONCLUSIONS: The GA-specific perinatal outcome results of this large cohort provide information to assist in perinatal management decision making and for counseling parents prenatally.

Análisis descriptivo de partos gemelares: Hospital de San Javier 1986-1991 / Descriptive analysis of twin labors: Hospital of San Javier 1986-1991

En el Hospital de San Javier, catalogado como tipo 4, se efectuó estudio retrsopectivo de los partos gemelares entre los años 1986 y 1991 con el objeto de evidenciar la realidad local en este tema y proponer conductas para mejorar la atención entregada a nuestra comunidad. Se recopiló la información del libro de registro de partos de nuestra maternidad. En el universo estudiado (5.304 partos), 35 partos fueron gemelares (0,66 por ciento), lo que se acerca a las cifras de la literatura nacional e internacional (menos del 1 por ciento). El porcentaje de partos gemelares fue resuelto por vía vaginal (63 por ciento), lo que concuerda con una conducta obstétrica actual en condiciones ideales. En relación a la puntuación del test de Apgar no encontramos diferencia importante entre los gemelos nacidos por vía alta o baja; si destacamos la existencia de recién nacidos con asfixia severa, en 3 casos (7 por ciento) de los naciods por vía vaginal. Concluímos que con los antecedentes expuestos podemos proponer, como conducta, la interrupción programada y electiva por vía cesárea de las madres embarazadas con gemelos, debido a lo distante que nos encontramos de una situación y realidad de trabajo ileal

The contribution of twins to perinatal mortality in Jamaica.

The Jamaican Perinatal Mortality Survey collected data that have been used in this paper to estimate: (1) the rate of multiple deliveries on the island; (2) the way in which this varies with demographic features; and (3) the causes of perinatal mortality among twins on the island. The survey consisted of two phases: a study of all births in the months of September and October 1986 (the cohort months) and a study of all perinatal deaths in the 12 months from 1 September 1986 to 31 August 1987. Among the 10,408 pregnancies in the cohort months, 99(1.0%) were multiple pregnancies. The twinning rate showed statistically significant trends with maternal age and parity but no association with social factors. Among the 2020 perinatal deaths occurring in the 12-month period, 173 (8.6%) were twins, with particularly high contribution to the Wiggles-worth group 'deaths from immaturity'. Mortality rate of twins was significantly lower if mothers resided in areas where there were good obstetric and paediatric facilities.

The contribution of twins to perinatal mortality in Jamaica

The Jamaican Perinatal Mortality Survey collected data that have been used in this paper to estimate: (1) the rate of multiple deliveries on the island; (2) the way in which this varies with demographic features; and (3) the causes of perinatal mortality among twins on the island. The survey consisted of two phases: a study of all births in the months of September and October 1986 (the cohort months) and a study of all perinatal deaths in the 12 months from 1 September 1986 to 31 August 1987. Among the 10408 pregnancies in the cohort months, 99 (1.0 percent) were multiple pregnancies. The Twinning rate showed statistically significant trends with maternal age and parity but no association with social factors. Among the 2020 perinatal deaths occurring in the 12-month period, 173 (8.6 percent) were twins, with particularly high contribution to the Wigglesworth group 'deaths from immaturity'. Mortality rate of twins was significantly lower if mothers resided in areas where there were good obstetric and paediatric facilities (Summary)