Weight growth of triplet infants from birth to twelve years of age

The New West Japan Twins and Higher Order Multiple Births Registry

The new West Japan Twins and Higher Order Multiple Births Registry was established by recruiting young twins and multiple births and by referrals from public health centers in the 1990s. The participants included in the survey comprised over 7800 twins and 4241 higher order multiples, and their families. Specifically, the present registry contains one of the largest triplet samples in the world. For these twins and multiples, data on year of delivery, mode of delivery, gestational age, intrapartum complications, longitudinal physical measures, motor milestones, cerebral palsy and feeding methods were obtained from records in the Maternal and Child Health Handbooks and schools. Participating mothers were asked to indicate family structure, parental educational history, maternal sleeping time, maternal health condition, maternal and paternal age at multiple delivery, complications during pregnancy, handedness of multiples and age at menarche of multiples. However, the zygosity differed among the various collaborating public health centers according to factors such as the time of investigation. Follow-up questionnaires have been mailed out every 3-4 years for longitudinal studies. This article describes the goals of this registry, recruitment of multiples and the focus of the study. The goals of this registry are not only to conduct research on human genetics and maternal and child health, but also to contribute to providing appropriate information for families with multiples.

Social modifications of the multiple birth effect on IQ and body size: a population-based study of young adult males

BACKGROUND

Twins and triplets fall behind singletons in cognitive and physical development. We analysed whether these differences are modified by family social position.

METHODS

IQ, height, body mass index (BMI) and elbow flexion, handgrip and knee extension strength were measured in Swedish men born between 1951 and 1976 during the conscription examination at 17 to 20 years of age. Information from Swedish registers on all siblings and parental socio-economic position were linked to these measures. Together, the measures were available for 1,140,329 singletons, 19,55 twins and 207 triplets. The data were analysed using regression analyses and fixed-effect models which compare twins and triplets with their singleton brothers.

RESULTS

Twins and triplets had slightly lower IQ, height, BMI and muscle strength than did singletons both at the population level as well as when compared with their singleton brothers. Although the differences between twins and triplets were small, they were largest in families with lower socio-economic position. We also found larger differences in IQ among the sons of mothers born before 1940.

CONCLUSIONS

Twins and triplets fall slightly behind singletons in cognitive and physical development, even in early adulthood, but twins and triplets show no major differences. These differences are largest in families in a low socio-economic position. Our results underscore the importance of the postnatal environment in the development of twins and triplets and suggest that their parents, especially those in a low socio-economic position, need special support.

Development of body mass index of Japanese triplets from birth until the onset of puberty

We aimed to analyze the characteristics of development of relative weight in Japanese triplets from birth until 12 years of age. Data were collected through a mailed questionnaire sent to mothers of triplets asking for information recorded in medical records. Altogether we had information on 1,061 triplet children of 354 mothers born between 1978 and 2006. For these births, data on triplets' height and weight growth, gestational age, sex, parity, and maternal age at delivery were obtained from records in the maternal and child health handbooks and records from the schools where children receive health check-ups. In addition, information on maternal height and weight was obtained. Triplets have a lower ponderal index at birth and lower body mass index (BMI) compared with the general population until 12 years of age, except for the period during 1 and 3 years of age. Moreover, birth weight had the strongest contribution to BMI of triplets until 6 years of age. After 9 years of age, maternal BMI was a significant factor affecting BMI of triplets.

The West Japan Twins and Higher Order Multiple Births Registry

The West Japan Twins and Higher Order Multiple Births Registry was established in the 1990s by recruiting young twins and multiples and through referrals from public health centers. To date, over 7,000 twins and 4,300 higher order multiple births and their families have been registered in the survey, and it includes one of the largest triplet samples in the world. Follow-up questionnaires are also mailed every 2 to 3 years as part of longitudinal survey studies. This article describes the goals of the registry, the recruitment of multiples, and the overall focus of the study. The goals of the registry are not only to provide data for research on human genetics and maternal and child health, but also to provide appropriate information for families with multiples.