Background Studies are sparse and inconclusive about the association between maternal education and cognitive development among children born very preterm (VPT). Although this association is well established in the general population, questions remain about its magnitude among children born VPT whose risks of medical and developmental complications are high. We investigated the association of maternal education with cognitive outcomes in European VPT birth cohorts. Methods We used harmonized aggregated data from 15 population-based cohorts of children born at <32 weeks of gestational age (GA) or <1500 g from 1985 to 2013 in 13 countries with information on maternal education and assessments of general development at 2–3 years and/or intelligence quotients between 4 and 15 years. Term-born controls (≥37 weeks of GA) were available in eight cohorts. Maternal education was classified as: low (primary/lower secondary); medium (upper secondary/short tertiary); high (bachelor’s/higher). Pooled standardized mean differences (SMDs) in cognitive scores were estimated (reference: high educational level) for children assessed at ages 2–3, 4–7 and 8–15 years. Results The study included 10 145 VPT children from 12 cohorts at 2–3 years, 8829 from 12 cohorts at 4–7 years and 1865 children from 6 cohorts at 8–15 years. Children whose mothers had low, compared with high, educational attainment scored lower on cognitive measures [pooled unadjusted SMDs: 2–3 years = −0.32 (95% confidence intervals: −0.43 to −0.21); 4–7 years = −0.57 (−0.67; −0.47); 8–15 years = −0.54 (−0.72; −0.37)]. Analyses by GA subgroups (<27 vs ≥27 weeks) in children without severe neonatal morbidity and term controls yielded similar results. Conclusions Across diverse settings and regardless of the degree of prematurity, low maternal education was associated with lower cognition.

Background: Chorioamnionitis, a risk factor for preterm delivery, has been suggested to be associated with suboptimal neurological development in premature infants. Objective: To evaluate the association between chorioamnionitis and neurodevelopment in preterm infants at 5 years of age. Methods Very low birth weight and very low gestational age infants (n = 197) were recruited. Placental samples (n = 117) were evaluated for histological chorioamnionitis. Fetal histological chorioamnionitis was analyzed as a subgroup. The diagnosis of clinical chorioamnionitis was derived from medical records. Neurodevelopmental impairments were evaluated at 2 years of age, and cognitive development (n = 188) and neuropsychological performance (n = 193) were evaluated at 5 years of age. Results: There were no associations between histological or clinical chorioamnionitis and neurodevelopmental impairments at 2 years of age.Clinical chorioamnionitis and fetal histological chorioamnionitis were not associated with cognitive development or neuropsychological performance, but histological chorioamnionitis was associated with poorer cognitive outcome (regression coefficient = -7.22, 95% CI: -14.31 to -0.13) and weaker memory and learning functions (regression coefficient = -1.29, 95% CI: -2.40 to -0.18) at 5 years of age. Conclusion: Our study findings do not support clinical chorioamnionitis having a major independent role in the pathogenesis of neurodevelopmental problems in very preterm infants. Histological chorioamnionitis was associated with slightly less optimal performance at 5 years of age, but further studies are needed to verify the clinical significance of these findings.

It seems that there are both benefits and risks with regard to the effects of chorioamnionitis on the brain development of preterm infants. It is plausible that inflammation enhances maturation of the preterm infant and therefore has protective effects balancing its potential harmful effects. We conclude that chorioamnionitis does not carry higher risks for the brain of preterm infants than other underlying pathologies behind preterm delivery.

Background: Preterm infants are still at an increased risk for suboptimal neurodevelopmental outcomes when compared with term born infants. The development of a child born preterm can be jeopardized by suboptimal conditions during pregnancy, in addition to the suboptimal growth environment postnatally compared to the normal in utero environment. This review summarizes the literature on the role of chorioamnionitis, placental insufficiency, and maternal smoking on the developmental outcomes of preterm infants. Methods: A systematic database search was performed to identify all original articles published on or before September 12, 2018 that evaluated the impact of clinical or histological chorioamnionitis, abnormal prenatal fetal and placental blood flow, and prenatal smoking exposure on the neuropsychological and cognitive outcomes of preterm infants. We identified a total of 54 studies. Thirty five original articles evaluated the effects of clinical or histological chorioamnionitis; 15 studies evaluated the effects of abnormal blood flow patterns; and four studies evaluated the effects of maternal smoking during pregnancy. Results: The studies on prenatal risk factors showed conflicting results about the impact on the neurodevelopment of preterm infants. The majority of the studies did not show that chorioamnionitis poses a direct risk to the development of preterm infants. The role of abnormal prenatal placental and fetal blood flow on the development of preterm infants remained inconclusive because the sample sizes were often small and methodological problems complicated the interpretation of the data. Maternal smoking during pregnancy was assessed only in one cohort which showed that maternal smoking is a risk for suboptimal cognitive and neuropsychological development in preterm infants. Conclusions: This review summarizes the data on several prenatal risk factors which play a role in the developmental outcomes of preterm infants. To optimize the developmental outcomes, we need to first optimize the fetal wellbeing before birth. More research that extends from the fetal life to long-term developmental outcomes is needed.