The prevalence of chemical substance and alcohol abuse in an obstetric population in Dublin.

Objective: To determine the prevalence of illicit drug abuse and alcohol use in an obstetric population based in an urban maternity hospital.
Setting: A collaborative study between the Rotunda Hospital, Dublin and the Irish National Drug Advisory & Treatment Centre.
Design: A prospective study consisting of anonymous, unlinked urine testing of 504 'first visit' antenatal patients and a separate group of 515 patients six weeks after delivery.
Methods & Outcome Measures: Toxicological screening using enzyme-linked immunoassay techniques, with all positive samples being reanalysed. Drug histories were taken and samples were tested for alcohol and six of the most commonly abused drugs. The pre- and postnatal prevalence of abuse was matched with demographic data.
Results: The prevalence of chemical substance misuse in the antenatal population was 2.8% and 5.6% in the postnatal population. Substances identified included benzodiazepines, cannabis, amphetamines, opiates and cocaine. Less than 2% of samples tested positive for alcohol. None of the women yielding positive samples had been pre-identified on the basis of history. A significant proportion of the women were in the high risk categories with regard to age and socio-economic status.
Conclusion: The prevalence of drug misuse antenatally was nearly 3% and postnatally almost 6%. Substance abusers in pregnancy are more likely to be single, unemployed, and to have had a previous pregnancy.