Relative contributions of prenatal complications, perinatal characteristics, neonatal morbidities and socio-economic conditions of preterm infants on the occurrence of developmental disorders up to 7 years of age

Background: To investigate the relative contributions of prenatal complications, perinatal characteristics, neonatal morbidities and socio-economic conditions on the occurrence of motor, sensory, cognitive, language and psychological disorders in a large longitudinal preterm infant population during the first 7 years after birth. Methods: The study population comprised 4122 infants born at <35 weeks of gestation who were followed for an average of 74.0 months after birth. Developmental disorders, including motor, sensory, cognitive, language and psychological, were assessed at each follow-up visit from 18 months to 7 years of age. The investigated determinants included prenatal complications (prolonged rupture of membranes >24 hours, intrauterine growth restriction, preterm labour and maternal hypertension), perinatal characteristics (gender, multiple pregnancies, gestational age, birth weight, APGAR score and intubation or ventilation in the delivery room), neonatal complications (low weight gain during hospitalization, respiratory assistance, severe neurological anomalies, nosocomial infections) and socio-economic characteristics (socio-economic level, parental separation, urbanicity). Based on hazard ratios determined using a propensity score matching approach, population-attributable fractions (PAF) were calculated for each of the four types of determinants and for each developmental disorder. Results: The percentages of motor, sensory, cognitive, language and psychological disorders were 17.0, 13.4, 29.1, 25.9 and 26.1%, respectively. The PAF for the perinatal characteristics were the highest and they were similar for the different developmental disorders considered (around 60%). For the neonatal and socio-economic determinants, the PAF varied according to the disorder, with contributions of up to 17% for motor and 27% for language disorders, respectively. Finally, prenatal complications had the lowest contributions (between 6 and 13%). Conclusions: This study illustrates the heterogeneity of risk factors on the risk of developmental disorder in preterm infants. These results suggest the importance of considering both medical and psycho-social follow-ups of preterm infants and their families

Impact of mode of conception on neonatal and neurodevelopmental outcomes in preterm infants

STUDY QUESTION: Is assisted conception associated with neonatal morbidity and mortality and with neurodevelopmental impairment at 2 years of corrected age in preterm infants born before 34 weeks of gestational age? SUMMARY ANSWER: Assisted conception is not associated with an increase in neonatal morbidity and mortality and is even significantly associated with a better 2-year neurodevelopmental outcome in preterm infants. WHAT IS KNOWN ALREADY: Assisted conception appears to increase the rate of preterm births, though few studies have analysed outcomes for these preterm infants. STUDY DESIGN, SIZE, DURATION: This prospective observational study included 703 preterm infants born between January 2009 and December 2013 and 573 of them were assessed at 2 years of corrected age. PARTICIPANTS/MATERIALS, SETTING, METHODS: All infants born alive between 24+0 and 33+6 weeks of gestational age and hospitalised at the Angers University Hospital were eligible as long as the mode of conception was known for neonatal outcome assessment. They were enroled in the Loire Infant Follow-up Team (LIFT) prospective longitudinal cohort and included for neurodevelopmental outcome assessment. Neonatal morbidity and mortality were evaluated during hospitalisation based on a composite score including death, intraventricular haemorrhage Grade ≥3, periventricular leukomalacia, treated patent ductus arteriosus and bronchopulmonary dysplasia at 36 weeks of gestational age. The neurodevelopmental outcome at 2 years of corrected age was determined by a physical examination, a neuropsychological test and a parental questionnaire. In order to ensure comparability, infants were matched 1:1 according to maternal age, twin status and propensity score,calculated from variables usually associated (positively or negatively) with assisted conception, including gestational age, z-score of birth weight, antenatal corticosteroids and magnesium sulphate treatments, gender, parity, maternal body mass index, tobacco consumption, outborn delivery (i.e. not at a tertiary-care medical centre) and maternal socio-economic status. MAIN RESULTS AND THE ROLE OF CHANCE: There were 703 preterm infants included in the analysis of neonatal morbidity and mortality, including 137 born after assisted conception. After matching, 184 preterm infants were included for neonatal morbidity and mortality analysis. There was no significant association between assisted conception and neonatal morbidity and mortality (aOR 0.67, 95% CI [0.25, 1.77], P = 0.422). 573 infants were assessed at 2 years, including 121 born after assisted conception. After matching, 154 preterm infants were included for neurodevelopmental outcome analysis. Assisted conception was significantly associated with a reduction in the probability of non-optimal neurological development at 2 years (aOR 0.26, 95% CI [0.09, 0.80], P = 0.019). LIMITATION, REASONS FOR CAUTION: Further studies remain necessary to fully confirm these results. This was a monocentric study and 14% of enroled infants were lost to follow up at 2 years of corrected age. WIDER IMPLICATIONS OF THE FINDINGS: These findings are relevant for providing appropriate information to parents considering assisted conception, and more importantly for those with a preterm infant following a pregnancy achieved by assisted conception. STUDY FUNDING/COMPETING INTEREST(S): The authors report external funding and no conflicts of interest for this work. TRIAL REGISTRATION NUMBER: N/A

Relative contributions of neighbourhood and animal movements to Coxiella burnetii infection in dairy cattle herds

Q fever in dairy cattle herds occurs mainly after inhalation of contaminated aerosols generated from excreta by shedder animals. Propagation of Coxiella burnetii, the cause of the disease between ruminant herds could result from transmission between neighbouring herds and/or the introduction of infected shedder animals in healthy herds. The objective of this study were (i) to describe the spatial distribution C. burnetii-infected dairy cattle herds in two different regions: the Finistère District in France (2,829 herds) and the island of Gotland in Sweden (119 herds) and (ii) to quantify and compare the relative contributions of C. burnetii transmission related to neighbourhood and to animal movements on the risk for a herd to be infected. An enzyme - linked immunosorbent assay was used for testing bulk tank milk in May 2012 and June 2011, respectively. Only one geographical cluster of positive herds was identified in north-western Finistère. Logistic regression was used to assess the association of risk for a herd to test positively with local cattle density (the total number of cattle located in a 5 km radius circle) and the in-degree (ID) parameter, a measure of the number of herds from which each herd had received animals directly within the last 2 years. The risk for a herd to test positively was higher for herds with a higher local cattle density [odds ratio (OR) = 2.3, 95% confidence interval (CI) = 1.6-3.2, for herds with a local density between 100 and 120 compared to herds with a local density 60]. The risk was also higher for herds with higher IDs (OR = 2.3, 95% CI = 1.6-3.2, for herds with ID 3 compared to herds that did not introduce animals). The proportion of cases attributable to infections in the neighbourhood in high-density areas was twice the proportion attributable to animal movements, suggesting that wind plays a main role in the transmission