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Objectives This prospective birth cohort study evaluated the effect of occupational exposure to endocrine disrupting chemicals (EDC) during pregnancy on inadequate fetal growth as measured by small-for-gestational age (SGA) and inadequate fetal growth measured by percentage of optimal birth weight (POBW). The study also identified the maternal characteristics associated with an increased risk of exposure to EDC. Methods We studied 4142 pregnant women who were in paid employment during pregnancy and participated in a population-based, prospective 2007-2011 birth cohort study, the Born in Bradford Study, with an estimated participation of 80%. Job titles were coded at 26-28 weeks` gestation at a 4-digit level according to 353 unit groups in the 2000 UK Standard Occupational Classification. They were then linked to expert judgment on exposure to each of ten EDC groups as assessed through a job exposure matrix (JEM). We performed generalized estimation equation modelling by a modified Poisson regression to assess the risk of POBW and SGA associated with an increased risk of chemical exposures. Results The frequency of POBW<85 significantly increased for mothers exposed to pesticides [adjusted risk ratio (RRadj) 3.72, 95% confidence interval (CI) 1.40-9.91] and phthalates (RRadj 3.71, 95% CI 1.62-8.51). There was a 5-fold increase risk of SGA for mothers exposed to pesticides (RRadj 5.45, 95% CI 1.59-18.62). Veterinary nurses and horticultural trades were most frequently associated with exposure to pesticides while hairdressers, beauticians, and printing machine minders were associated with phthalates. Conclusion Maternal occupational exposure to estimated concentrations of pesticides and phthalates is associated with impaired fetal growth.

The etiology of childhood cancers is largely unknown, although the early age at diagnosis has led to particular interest in in utero and perinatal factors. Birth weight is the most frequently studied perinatal factor in relation to risk of childhood cancers, and results have been inconsistent. We investigated whether the risk of CNS tumors and lymphomas in children was associated with three measures of the appropriateness of intra-uterine growth: proportion of optimal birth weight (POBW), birth length (POBL) and weight for length (POWFL). A cohort of 576,633 infants born in Western Australia in 1980-2004 were followed from birth to diagnosis of a CNS tumor (n = 183) or lymphoma (n = 84) before age 15, death, or December 31, 2005, and analyzed with Cox regression. Overall, there was little evidence of any association between fetal growth and risk of CNS tumors, although risk of ependymoma/choroid plexus tumors was positively associated with POBL and negatively associated with POWFL. The risk of Hodgkin and Burkitt lymphoma increased with increasing fetal growth among boys only, whereas the increased risk observed with non-Hodgkin lymphoma was only in girls. These associations between fetal growth and disease risk were also observed among children not classified as high birth weight, suggesting that accelerated growth is more important than birth weight per se. Results were similar when cases were compared with their unaffected siblings, suggesting that the increased growth associated with cancer risk was not general to the family. The associations we observed are consistent with causal pathways involving fetal growth factors., ((c) 2008 Wiley-Liss, Inc.)

The authors examined the relation between birth weight, intrauterine growth, and risk of childhood leukemia using population-based linked health data from Western Australia. A cohort of 576,593 infants born in 1980-2004 were followed from birth to diagnosis of acute lymphoblastic leukemia (ALL) (n = 243) or acute myeloid leukemia (AML) (n = 36) before their 15th birthday, death, or the end of follow-up (December 31, 2005). Data were analyzed using Cox regression. Risk of ALL was positively associated with the proportion of optimal birth weight--a measure of the appropriateness of fetal growth--particularly among children younger than 5 years; the hazard ratio for a 1-standard-deviation increase in proportion of optimal birth weight was 1.25 (95% confidence interval: 1.07, 1.47). Among children younger than 5 years not classified as having high birth weight (defined as >3,500 g, >3,800 g, and >4,000 g), a 1-unit increase in proportion of optimal birth weight was associated with an approximately 40% increase in ALL risk. This suggests that accelerated growth, rather than high birth weight per se, is involved in the etiology of ALL. These findings are consistent with a role for insulin-like growth factor I in the causal pathway. Findings for AML were inconclusive, probably because of small numbers.

When birth weight for gestation is used as a surrogate for intrauterine growth, the prevalence of cerebral palsy varies continuously in a reversed J shape, with steep increases in the risk for infants lighter and heavier than the optimum size. Patterns of size-at-birth specific risk for cerebral palsy differ between male and female infants, as do the patterns for more severe versus milder cases. Although these excess risks with abnormal size at birth imply antenatal precursors, it is not clear whether or how intrauterine growth is involved in any of the suspected causal pathways resulting in cerebral palsy. The implication for clinicians is that serial measures of in utero growth may provide an important indicator of fetal health.

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.

Background Understanding the effect of occupational exposure to endocrine disrupting chemicals (EDC) during pregnancy on inadequate fetal growth as measured by small-for-gestational age (SGA) and as measured by percentage of optimal birth weight (POBW) is not well understood. Methods We studied 4142 pregnant women who were in paid employment during pregnancy and participated in a population-based, prospective 2007–2011 birth cohort study, the Born in Bradford Study, with an estimated participation of 80%. Job titles were coded at 26–28 weeks' gestation at a 4-digit level according to 353 unit groups in the 2000 UK Standard Occupational Classification. They were then linked to expert judgment on exposure to each of ten EDC groups as assessed through a job exposure matrix. A modified Poisson regression was used to assess the risk of POBW and SGA associated with an increased risk of chemical exposures. Results The frequency of POBW<85 significantly increased for mothers exposed to pesticides [adjusted risk ratio (RRadj) 3.72, 95% confidence interval (CI) 1.40–9.91] and phthalates (RRadj 3.71, 95% CI 1.62–8.51). There was a 5-fold increase risk of SGA for mothers exposed to pesticides (RRadj 5.45, 95% CI 1.59–18.62). Veterinary nurses and horticultural trades were most frequently associated with exposure to pesticides while hairdressers, beauticians, and printing machine minders were associated with phthalates. Conclusion Maternal occupational exposure to estimated concentrations of pesticides and phthalates is associated with impaired fetal growth. Key messages The POBW is useful in measuring inadequate fetal growth in study of occupational chemical exposures. [ABSTRACT FROM AUTHOR]

Objective The objective of the study was to improve the understanding of etiological paths to cerebral palsy (CP) that include fetal growth restriction by examining factors associated with growth restriction that modify CP risk. Study Design In a total population of singletons born at or after 35 weeks, there were 493 children with CP and 508 matched controls for whom appropriateness of fetal growth could be estimated. Fetal growth was considered markedly restricted if birthweight was more than 2 SD below optimal for gender, gestation, maternal height, and parity. We examined maternal blood pressure in pregnancy, smoking, birth asphyxia, and major birth defects recognized by age 6 years as potential modifiers of CP risk in growth-restricted births. Results More than 80% of term and late preterm markedly growth-restricted singletons were born following a normotensive pregnancy and were at statistically significantly increased risk of CP (odds ratio, 4.81; 95% confidence interval, 2.7–8.5), whereas growth-restricted births following a hypertensive pregnancy were not. Neither a clinical diagnosis of birth asphyxia nor potentially asphyxiating birth events occurred more frequently among growth-restricted than among appropriately grown infants with CP. Major birth defects, particularly cerebral defects, occurred in an increasing proportion of CP with increasing growth deficit. The factor most predictive of CP in growth-restricted singletons was a major birth defect, present in 53% of markedly growth-restricted neonates with later CP. Defects observed in CP were similar whether growth restricted or not, except for an excess of isolated congenital microcephaly in those born growth restricted. The highest observed CP risk was in infants with both growth restriction and a major birth defect (8.9% of total CP in this gestational age group, 0.4% of controls: odds ratio, 30.9; 95% confidence interval, 7.0–136). Conclusion The risk of CP was increased in antenatally growth-restricted singletons born at or near term to normotensive mothers. In growth-restricted singletons, a major birth defect was the dominant predictor, associated with a 30-fold increase in odds of CP. Identification of birth defects in the growth-restricted fetus or neonate may provide significant prognostic information. [ABSTRACT FROM AUTHOR]

Objective: We sought to investigate whether placental infarction determined by macroscopic examination was associated with risk of cerebral palsy (CP). Study Design: This was a population-based study of macroscopic placental infarcts in singletons >35 weeks'' gestational age, in 158 perinatal deaths, 445 infants with CP, and 491 controls matched with CP cases for gestational age. Results: Placental infarcts were recorded in 2.0% of controls, 4.4% of deaths (relative risk [RR], 2.2; 95% confidence interval [CI], 0.8–5.6]), 5.2% of infants with CP (P < .05, RR, 2.5; 95% CI, 1.2–5.3), and 8.4% with spastic quadriplegic CP (P = .0026; RR, 4.4; 95% CI, 1.8–10.6). In children with CP, unlike controls, placental infarction was associated with reduced fetal growth, older maternal age, more prior miscarriages, and poor neonatal condition, but not with maternal preeclampsia. Conclusion: Placental infarction identified by macroscopic examination was associated with increased risk of CP and the CP subtype, spastic quadriplegic CP. Antecedents of placental infarction differed in children with CP compared with control children. [Copyright &y& Elsevier]