Abstract Background: Stigmatized behaviours are often underreported, especially in pregnancy, making them challenging to address. The Alcohol and Child Development Study (ACDS) seeks to inform prevention of foetal alcohol harm, linking self report as well as a maternal blood alcohol biomarker with child developmental outcomes. Methods: Maternity records from all pregnant women in the study city who presented for maternity care during the 12 month period June 2017 to June 2018 were transferred to the safe data facility creating the baseline cohort. Health Visitor routinely recorded child developmental screening data collected when the offspring were 30 months of age were transferred and linked to the cohort. Anonymous analysis was performed to assess associations between self reported alcohol intake collected at maternity presentation with child development concerns and looked after by the local authority status of offspring at 30 months of age. Chi2 tests of association were used. Results: 14919 maternity records were transferred and 10876 could be linked to developmental screening data collected at 30 months of age. As expected self reported current alcohol use after conception measured at presentation to maternity care was associated with offspring being looked after by the local authority (chi2=7.85, p=0.005) at age 30 months. 6.6% of children in care were attributable to self report of current alcohol use during pregnancy. Developmental outcomes were generally inversely associated with self-report of current alcohol use notably concern regarding Social Development (chi2=4.08, p=0.043) and Speech, Language or Communication Development (chi2=4.37, p=0.037). Conclusions: Explanation for this unexpected inverse relationship may relate to known miss-representation of alcohol intake from maternal self report (the risk) or inaccurate assessment of offspring development at 30 months (the outcome). However self report of current intake at maternity presentation prompts an alcohol intervention which if effective might explain the anomalous findings. Keywords: Clinical markers, Cohort study, Data collection, Demography, Epidemiology

The authors have declared no competing interest.

NHS Greater Glasgow & Clyde Endowments Fund (now Greater Glasgow and Clyde Healthcare charity) and Glasgow Children's Hospital Charity

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West of Scotland Research Ethics Committee 5 of West of Scotland Research Ethics Service gave ethical approval for this work

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