Reference Birth Weight, Length, Chest Circumference, and Head Circumference by Gestational Age in Japanese Twins

Abstract

BACKGROUND: Numerous birth weight standards for twins have been reported in western countries , whereas little is in Japan. The aim of this study is to present birth weight , birth length, chest circumference, and head circumference references, clarifying features related to these body size parameters , and to compare our birth weight references with recent report of birth weight norms of Japanese twins using the vital statistics.METHODS: The subjects consisted of 1,061 twin pairs in total, with birth years ranging from 1968 through 1990. Data was obtained from the Twins Protocol Questionnaire , which asked for information about twins' growth and development in infancy , and the "Maternal and Child Health Handbook," which was presented by Ministry of Health and Welfare. Statistical means, standard deviations , and selected percentiles by gestational age were calculated and smoothed using data that contained at least gestational age and one of the four items.RESULTS: Birth weight was significantly lighter than that of singletons when three additional parameters, especially chest and head circumference, were not measured. Gestational age was correlated with weight, length, chest circumference, and head circumference, in that order , for both sexes. Compared with singletons, birth weight difference in twins was marked and slight difference was observed as to length, whereas no difference was observed as to chest and head circumference. The present results as to birth weight were consistently similar to the birth weight norms of twins using vital statistics in Japan.CONCLUSION: Growth standards for twins, especially as to birth weight, are essential to understand and evaluate intrauterine growth of twins.

Comparison of Obstetric and Birthweight Characteristics Between the Two Largest Databases of Japanese Twins Measured in Childhood

“…These included questions about family structure; obstetrical findings on the mothers; the twins' physical growth, zygosity, motor, language, and mental development; the twins' and parents' medical histories; and any behavioral problems the twins had had (Ooki & Yokoyama, 2003, 2004 tations and Japanese restrictions on epidemiological data collection. Obstetric findings were obtained from the Maternal and Child Health Handbook (which is presented by the Ministry of Health, Labor and Welfare to all pregnant women and whose format varies depending on the policies of each city).…”

Physical Growth Charts from Birth to Six Years of Age in Japanese Twins

“…As to height/length, the difference was nearly 6% at birth and gradually decreased after birth. Since there were many detailed standards for birth weight and length in twins according to gestational weeks 3 , growth charts after birth were calculated separately for males and females without taking gestational periods into consideration, following the system used to calculate standards for singletons. 20 The 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentile curves of weight and height/length from birth to 1 year of age are presented in Figure 2, and those from 1 to 6 years of age are presented in Figure 3.…”

“…However, compared with the hospital data, which usually include many high-risk subjects, the present data seem to reflect more closely the physical growth features of the general twin population. 3 Fourth, as the birth years of the present subjects ranged from 1968 to 2002, a period of 35 years, yearly trends in physical growth may also be considered. Fortunately, no birth-year effects were observed in the present study, as mentioned in the results of the stepwise regression analysis.…”

“…11 It is well known that the growth patterns of twins in utero and in childhood are very different from those of singletons. 3,[12][13][14] Because there are no growth standards for twins in Japan, the physical growth of twins in childhood must be evaluated using the standards for the general population 15 -that is, standards for singletons. As a result, many twins are regarded as having poor growth, especially when they are very young, and this causes both the twins and their parents much embarrassment and concern.…”

Strategy and Practice of Support for Families with Multiple Births Children: Combination of Evidence-Based Public Health (EBPH) and Community-Based Participatory Research (CBPR) Approach

“…Other body size parameters at birth, such as birth length, chest circumference, and head circumference have not been reported as consistently as birthweight. Selected percentiles by gestational age were calculated and smoothed (Ooki & Yokoyama, 2003). Compared with singletons, birth weight difference in twins was marked and slight difference was observed as to length, whereas no difference was observed as to chest and head circumference.…”