Author	H.R. Davies
Author	I. Petersen
Author	I. Nazareth
Author	F. Stevenson
Abstract	Background: Misuse of drugs is a public health problem which can lead to poor health outcomes. Drug use during pregnancy could potentially harm the unborn baby. Pregnancy usually triggers women to visit their general practitioner (GP) which may provide an opportunity for drug use to be raised and recorded. To date, there are no UK studies with large sample sizes to estimate the burden of drug use during pregnancy. Therefore, my aim was to describe and understand drug use and opioid substitution treatment in and around pregnancy using electronic health records. Methods: Using a mixed methods design, I firstly, utilized The Health Improvement Network (THIN) to estimate GP recording rates of individuals who use drugs and/or are prescribed opioid substitution treatment in the general population, of women in and around pregnancy and infants with neonatal abstinence syndrome (NAS). Next, I compared rates with national surveys and hospital birth data. Finally, I conducted qualitative interviews to gain GPs' perspectives regarding their decisions about recording drug-use. Results: GP recording trends for the general population were in keeping with national surveys, but with lower rates. Recording was relatively low in and around pregnancy. GP recording of NAS was similar to hospital data, however rates were lower. Finally, qualitative interview analysis identified that influences on recording drug use were complex and related to pressures at the individual as well as organisational (general practices, Clinical Commissioning Groups) and governmental levels in the shape of government policies. Conclusion: In conclusion, evidence from the thesis supports the use of THIN as a suitable tool for monitoring trends but not rates of problem drug use in the general population. Electronic primary health records could potentially be used to monitor the impact of problematic drug use in and around pregnancy. The thesis also supports utilising THIN for researching drug use and opioid substitution treatment in the general population.