Anthropometric measurements for neonates, 23 to 29 weeks gestation, in the 1990s

Abstract

Reference data describing weight, length, and head circumference (anthropometric measurements) at birth were published by Lubchenco and Usher before 1970. Few attempts have been made to investigate whether these data are appropriate for today's cohort of preterm neonates. We analysed anthropometric data for neonates born between 23 and 29 weeks' gestation. Reference charts were developed from the measurements obtained from neonatal records, and gestational age, obtained from maternal charts, on 975 neonates delivered at four neonatal centres in Michigan during 1992 and 1997. The analysis was confined to children with gestational age that was consistent or within 7 days by last menstrual period, obstetric examination, ultrasound and neonatal determinations. At 23 to 29 weeks' gestation, ethnicity and multiple births did not have any significant impact on birthweight but girls were lighter. We compared our anthropometric charts with those presently being used at many neonatal centres. In our study, physical measurements at birth of preterm neonates born between 1992 and 1997 were significantly different from those currently used to assess growth status. Furthermore data derived from published studies that utilised birth certificates with gestational age based on last menstrual period seem to overestimate birthweight. For preterm infants, our findings are concordant with recently published values from 18 states of the US. Because of improved survival, gestational age assessment and perinatal care of preterm neonates, development of new reference anthropometric measurements for neonates is overdue. Our Michigan data of 23-29 weeks preterm provides new national reference values, which we recommend for use in US neonatal centres for extremely preterm neonates.

New Intrauterine Growth Curves Based on United States Data

“…Cross-sectional birth data do not represent growth over time; however, these do represent intrauterine growth of fetuses up to the time of birth, which is the American Academy of Pediatrics's recommended goal for preterm infants. 1 Preterm infants at birth are smaller in size than fetuses of the same GA, 16,33,34 and error in GA dating is a widely known concern because of the questions that it brings to the accuracy of the size/age relationships represented in growth curves 31,35,36 ; however, the use of ultrasound data for estimating size and GA dates has been associated with error, 9,37,38 it is not a direct measurement of fetal size, 9,32 and it is not feasible in a large study of infants. Despite the limitations, cross-sectional birth data from infants of varying ages remain the generally accepted best sources for creating growth curves for the assessment of infant size at birth and postnatally.…”

Recent Advances in Neonatal Gastroenterology and Neonatal Nutrition

“…There are more than 25 studies reporting on such 'intrauterine growth charts'. These have been best summarized by Karna et al (Karna et al 2005). Lubchenko 1963 (Lubchenco et al 1963) and Babson/Benda1976 (Babson andBenda 1976) charts are commonly used in many neonatal units around the world.…”

Neonatology fellowship training in research pertaining to development and follow-up

“…There is only one relatively small recent study of normative birth weightgestational age data in the United States. 36 …”