Subject(s)
Body Weights and Measures/standards , Growth Charts , Adolescent , Body Weights and Measures/methods , Child , Child Development/physiology , Child, Preschool , Decision Support Systems, Clinical/standards , Developmental Disabilities/diagnosis , Endocrinology/methods , Endocrinology/standards , Female , Growth Disorders/diagnosis , Humans , Internationality , Male , Patient Selection , Pediatrics/methods , Pediatrics/standards , Reference Standards , Reference Values , World Health Organization , Young AdultABSTRACT
BACKGROUND: Few studies have compared the growth of a twin with its co-twin and particularly in relation to birth weight discordance. AIM: The study investigated how the degree of birth weight discordance affected subsequent growth. METHODS: Birth weight discordance of 762 twin pairs was determined. Subsequent weight, height and occipital-frontal head circumference (OFC) measurements were obtained between the ages of 2-9 years. Corresponding standard deviations scores (SDS) were analysed according to birth weight discordance, sex and zygosity. Weight status was taken into account by assigning twins into sub-groups according to whether they were the heavier twin at birth and remained heavier, became the lighter of the twin pair or had the same weight, for subsequent measurements. RESULTS AND CONCLUSIONS: The degree of birth weight discordance had little effect on subsequent growth except in monozygotic (MZ) twins with >20% discordance. Severe low birth weight ( < 1.95 kg) is more significant in suppressing subsequent growth than the degree of discordance per se. A surprisingly high proportion of twins reversed their weight status when reviewed at an older age.
Subject(s)
Birth Weight/physiology , Growth and Development/physiology , Twins/physiology , Body Height/physiology , Cephalometry , Female , Humans , Male , Puberty/physiology , Twins, Dizygotic/physiology , Twins, Monozygotic/physiologyABSTRACT
BACKGROUND: Size at birth has an important relationship to subsequent growth. Many reports subgroup subjects according to birth weight or birth weight in relation to the duration of gestation, and it is not clear whether one of these methods is more relevant to subsequent growth or if in fact they are comparable. AIM: The present study compared the outcome of twins in terms of pre-pubertal weight and height when sub-grouped according to birth weight (BW), or the appropriateness of birth weight for the duration of gestation (BW-SDS). SUBJECTS AND METHODS: The birth weights of 1533 twins were graded into four subgroups according to BW or BW-SDS. The relationship of birth weight to subsequent weight and height standard deviation scores, obtained between the ages of 2 and 9 years, were compared on the basis of these two methods. RESULTS: There was a marked difference in identity of the twins who fell into each of the four subgroups by the two methods. Despite this, no difference was found in the subsequent weight and height of the twins. CONCLUSIONS: Analysis of data relating BW-SDS to subsequent growth shows no significant difference to those groups using BW alone.
Subject(s)
Birth Weight , Child Development , Gestational Age , Twins , Anthropology/methods , Body Height , Body Weight , Child , Child Development/physiology , Child, Preschool , Female , Follow-Up Studies , Humans , Infant, Newborn , Male , Twins/physiologyABSTRACT
BACKGROUND: Twin growth studies are mostly based on pooled data without consideration of zygosity, parental heights or birth weight. AIM: The study investigated the effects of gender, zygosity, parental height and birth weight on subsequent twin growth. METHODS: Height and weight measurements of 1533 twins (n = 1077 for occipito-frontal head circumference (OFC)), age range 2-9 years, were converted to standard deviation scores derived from singleton standards. Their growth was evaluated in relation to gender, zygosity, parental heights and birth weight. RESULTS: Mean stature of twins fell only slightly below the reference values of singletons, but they were underweight to a greater extent (boys more than girls). Twins' OFC were low (girls more so than boys). Monozygotic (MZ) twin boys were lighter and shorter than dizygotic twins and MZ twin girls. Deficient growth was most evident in those babies light at birth. Parental heights only partly accounted for the difference in height of twins. CONCLUSIONS: Birth weight and parental height are important in relation to subsequent growth. Boy twins are at a disadvantage compared with girls in terms of their growth in height and weight, particularly in the low birth weight and MZ groups.
Subject(s)
Body Height/genetics , Body Weight/genetics , Parents , Twins , Age Factors , Anthropometry , Birth Weight , Body Mass Index , Child , Child, Preschool , Female , Humans , Male , Sex Factors , Twin Studies as TopicABSTRACT
BACKGROUND: It is well known that the birth weight of twins is less than that of singletons, but there is less information about how birth lengths compare and how twins grow in the postnatal and early childhood period. The implications of the shorter duration of gestation of twins in comparing their postnatal progress with that of singletons are seldom taken into consideration. AIMS: The study aimed to compare the growth of healthy twins and singletons over the first 4 years of life. SUBJECTS AND METHODS: Birth length data on English twins born between 1990 and 1997 were used to produce reference values for gestational ages from 33 to 40 weeks. Follow-up data of weights and lengths up to the equivalent of 40 weeks' gestation are reported on some of these infants who were born pre-term. On the basis of questionnaires, the growth of twins in terms of weight, length/height and head circumference has been followed up to 4 years of age. RESULTS: Mean birth length of twins showed a fall-off when compared with singletons at comparable gestational ages, which was more marked in boys than girls and evident earlier. Extrauterine growth of twins born pre-term was comparable to that of adequately nourished twins remaining in utero until term. Much of the smallness of twins at birth was because of their shorter gestation. Subsequently singletons gained weight faster. Lengths/heights showed no deficit compared with singletons. Head circumferences of twins were, however, smaller than singletons throughout. CONCLUSIONS: The early growth of normal twins differs markedly from that of singletons. It is important to recognize that singleton reference values do not correctly reflect the growth of twins.
Subject(s)
Growth , Twins , Age Factors , Body Height , Body Weight/physiology , Child, Preschool , Female , Gestational Age , Head/anatomy & histology , Head/physiology , Humans , Infant , Infant, Newborn , Male , Reference Values , Sex FactorsABSTRACT
Since the introduction of new growth charts in the mid 1990s, there has been confusion about which charts should be used, with many districts using more than one version. Because of this uncertainty, an expert working party, the Growth Reference Review Group, was convened by the Royal College of Paediatrics and Child Health to provide guidance on the validity and comparability of the different charts currently in use. This paper describes the technical background to the construction and evaluation of growth charts and outlines the group's findings on the validity of each growth reference in relation to contemporary British children. The group concluded that for most clinical purposes the UK90 reference is superior and for many measures is the only usable reference that can be recommended, while the original Tanner-Whitehouse and the Gairdner-Pearson charts are no longer reliable for use at any age. After the age of 2 the revised Buckler-Tanner references are still suitable for assessing height. There are presently no reliable head circumference reference charts for use beyond infancy. The group propose that apart from refinements of chart design and layout, the new UK90 reference should now be "frozen", with any future revisions only undertaken after careful planning and widespread consultation.
