Search

Background: The aim of this study was to validate a model for optimal birth weight derived from neonatal records, and to test the assumption that preterm births may be considered optimally grown if they are not exposed to common factors that perturb fetal growth. Methods: Weights of fetuses were estimated from serial biometric ultrasound scans (N = 2,848) and combined with neonatal weights for a prospective pregnancy cohort (N = 691). Non-Caucasians, fetuses subsequently born preterm and those with diagnosed or suspected determinants of aberrant growth were excluded leaving fetuses assumed to have experienced normal growth. A generalised linear longitudinal growth model for optimal weight was derived, including terms for gestational duration, infant sex, maternal height and birth order. This model was compared to a published model derived solely from birth weights. Results: Prior to 30 weeks gestation, the published model yielded systematically lower weights than the model derived from both fetal weight and neonatal weight. From 30 weeks gestation the two models were indistinguishable. Conclusion: The model for optimal birth weight was valid for births that have attained at least 30 weeks gestation. The model derived from both fetal and neonatal weights is recommended prior to this gestation. [ABSTRACT FROM AUTHOR]

Background: The appropriateness of an individual's intra uterine growth is now considered an important determinant of both short and long term outcomes, yet currently used measures have several shortcomings. This study demonstrates a method of assessing appropriateness of intrauterine growth based on the estimation of each individual's optimal newborn dimensions from routinely available perinatal data. Appropriateness of growth can then be inferred from the ratio of the value of the observed dimension to that of the optimal dimension. Methods: Fractional polynomial regression models including terms for non-pathological determinants of fetal size (gestational duration, fetal gender and maternal height, age and parity) were used to predict birth weight, birth length and head circumference from a population without any major risk factors for sub-optimal intra-uterine growth. This population was selected from a total population of all singleton, Caucasian births in Western Australia 1998-2002. Births were excluded if the pregnancy was exposed to factors known to influence fetal growth pathologically. The values predicted by these models were treated as the optimal values, given infant gender, gestational age, maternal height, parity, and age. Results: The selected sample (N = 62,746) comprised 60.5% of the total Caucasian singleton birth cohort. Equations are presented that predict optimal birth weight, birth length and head circumference given gestational duration, fetal gender, maternal height, age and parity. The best fitting models explained 40.5% of variance for birth weight, 32.2% for birth length, and 25.2% for head circumference at birth. Conclusion: Proportion of optimal birth weight (length or head circumference) provides a method of assessing appropriateness of intrauterine growth that is less dependent on the health of the reference population or the quality of their morphometric data than is percentile position on a birth weight distribution. [ABSTRACT FROM AUTHOR]

Background: Late Language Emergence (LLE) in the first two years of life is one of the most common parental concerns about child development and reasons for seeking advice from health professionals. LLE is much more prevalent in twins (38%) than singletons (20%). In studies of language development in twins without overt disability, adverse prenatal and perinatal environments have been reported to play a lesser role in the etiology of LLE than adverse postnatal environments. However, there is a lack of population-level evidence about prenatal and perinatal risk factors for LLE in twins. This study investigated the extent to which prenatal and perinatal risk factors were associated with LLE in a population-level sample of twins at age 2 without overt disability.Methods: The sample comprised 473 twin pairs drawn from a population sample frame comprising statutory notifications of all births in Western Australia (WA), 2000-2003. Twin pairs in which either twin had a known developmental disorder or exposure to language(s) other than English were excluded. Of the 946 twins, 47.9% were male. There were 313 dizygotic and 160 monozygotic twin pairs. LLE was defined as a score at or below the gender-specific 10th percentile on the MacArthur Communicative Development Inventories: Words and Sentences (CDI-WS) (Words Produced). Bivariate and multivariable logistic regression was used to investigate risk factors associated with LLE.Results: In the multivariable model, risk factors for LLE in order of decreasing magnitude were: Gestational diabetes had an adjusted odds ratio (aOR) of 19.5 (95% confidence interval (CI) 1.2, 313.1); prolonged TSR (aOR: 13.6 [2.0, 91.1]); multiparity (aOR: 7.6 [1.6, 37.5]), monozygosity (aOR: 6.9 [1.7, 27.9]) and fetal growth restriction (aOR: 4.6 [1.7, 12.7]). Sociodemographic risk factors (e.g., low maternal education, socioeconomic area disadvantage) were not associated with increased odds of LLE.Conclusions: The results suggest that adverse prenatal and perinatal environments are important in the etiology of LLE in twins at age 2. It is important that health professionals discuss twin pregnancy and birth risks for delayed speech and language milestones with parents and provide ongoing developmental monitoring for all twins, not just twins with overt disability. [ABSTRACT FROM AUTHOR]