The Hertfordshire Cohort Study is a nationally unique study of men and women born in the English county of Hertfordshire in the early part of the 20th century. Records that detail their health in infancy and childhood have been preserved, their sociodemographic, lifestyle, medical and biological attributes have been characterised in later life, and routinely collected data on their hospital use and mortality have been acquired. This paper provides an overview of the study since its inception in the 1980s, including its methods, findings, and plans for its future.

Background: Studies have shown that air pollution exposures during pregnancy are associated with an increased risk of autism spectrum disorder (ASD) in children, and the risk appears to be greater for boys. However, studies assessing gestational windows of susceptibility have been mostly limited by trimesters. Objective: We identified sensitive windows of exposure to regional air pollution and risk of ASD and examined sex differences in a large birth cohort. Methods: This population-based retrospective cohort study included 294,937 mother–child pairs with singleton deliveries in Kaiser Permanente Southern California (KPSC) hospitals from 2001 to 2014. Children were followed using electronic medical records until clinical ASD diagnosis, non-KPSC membership, death, or 31 December 2019, whichever came first. Weekly mean fine particulate matter [PM with an aerodynamic diameter of ( )], nitrogen dioxide ( ), and ozone ( ) pregnancy exposures were estimated using spatiotemporal prediction models. Cox proportional hazard models with distributed lags were used to estimate weekly pollutant exposure associations with ASD risk for the entire cohort, and separately for boys and for girls. Models were adjusted for child sex (for full cohort), maternal race/ethnicity, maternal age at delivery, parity, maternal education, maternal comorbidities, medical center, census tract median household income, birth year, and season. Results: There were 5,694 ASD diagnoses (4,636 boys, 1,058 girls). Sensitive exposure windows associated with ASD were found early in pregnancy, statistically significant throughout the first two trimesters [1–27 wk of gestation, cumulative [95% confidence interval (CI): 1.06, 1.23] per interquartile range (IQR) ( ) increase]. exposure during 34–37 wk of gestation was associated with increased risk [ (95% CI: 1.01, 1.11) per IQR ( ) increase] but with reduced risk during 20–28 wk of gestation [ (95% CI: 0.89, 0.98)]. No associations were observed with . Sex-stratified early gestational associations were stronger among boys [boys (95% CI: 1.08, 1.26); girls (95% CI: 0.89, 1.26)]. associations in later gestation were observed only in boys [boys (95% CI: 1.04, 1.16); girls (95% CI: 0.84, 1.05)]. Conclusions: Exposures to in the first two gestational trimesters were associated with increased ASD risk in children, with stronger associations observed for boys. The role of exposure on ASD risk merits further investigation. https://doi.org/10.1289/EHP9509

Background: Labour induction is a childbirth intervention experienced by a growing number of women globally each year. While the maternal and socioeconomic indicators of labour induction are well documented in countries like the United States, considerably less research has been done into which women have a higher likelihood of labour induction in the United Kingdom. This paper explores the relationship between labour induction and maternal demographic, socioeconomic, and health indicators by parity in the United Kingdom.Method: Logistic regression analyses were conducted using the first sweep of the Millennium Cohort Study, including a wide range of socioeconomic factors such as maternal educational attainment, marital status, and electoral ward deprivation, in addition to maternal and infant health indicators.Results: In fully adjusted models, nulliparous and multiparous women with fewer educational qualifications and those living in disadvantaged places had a greater likelihood of labour induction than women with higher qualifications and women in advantaged electoral wards.Conclusions: This paper highlights which UK women are at higher risk of labour induction and how this risk varies by socioeconomic status, demonstrating that less advantaged women are more likely to experience labour induction. This evidence could help health care professionals identify which patients may be at higher risk of childbirth intervention.