The prevalence of substance use among pregnant women varies widely. The reported prevalence varies between 0.2 and 15% for alcohol, between 1.8% and 15% for cannabis, and between 0.3% and 9.5% for cocaine. The reported prevalence of opiate use during pregnancy ranges from 1.6% to 8.5%. The prevalence varies widely because of differences in the methods of assessment, gestational period of assessment and population characteristics. There is clear evidence that substance use in this population is an issue of real and serious concern. Most pregnant women stop or reduce their substance use during pregnancy and this might be an opportune moment for detection and treatment.

We report the prevalence of smoking, drinking and illicit substance use among 420 women attending for 20 week antenatal ultrasound scan in a UK University Hospital is reported. Routine antenatal recording of substance use among this population is compared with a focused interview and objective measurements for substance use. Change in use of substances in relation to pregnancy is also reported.