OBJECTIVES: Drugs used during pregnancy may cause potential harm to fetuses and pregnant women. Despite its dangers, the medication use among pregnant women in Korea has been rarely studied. We aim to investigate pregnant Korean women’s prescription drug use and to examine the prevalence of inappropriate prescribing associated with teratogenic risks during pregnancy.

METHODS: Pregnant women who had a diagnosis of delivery (ICD-10th code of O80-O84) and service code of delivery from October 1 through December 31, 2016 were identified as the study population by insurance claims data called 2016 Health Insurance and Review Assessment Service – National Patient Sample (HIRA-NPS) data. Drugs prescribed between 270 days to 7 days before delivery date were analyzed.

RESULTS: Of 2,296 pregnant women identified, 97.6% were prescribed with at least one medication with an average number of 9.53 drugs. The most frequently prescribed drug was glucose (96%). For outpatient visits, cough and cold preparation were prescribed most often followed by antibacterial for systemic use, whereas diagnostic agents were mostly prescribed for inpatient services. During each trimester, 63.9%, 82.1%, and 68.8% of the pregnant women were prescribed with at least one medication. About 4.2% of pregnant women experienced prescription drugs in the 1^st level of risk category by Ministry of Food and Drug Safety in Korea, which are not supposed to be prescribed during pregnancy due to known teratogenic risks. The most frequently prescribed drug in the 1^st level of risk category was dydrogestone followed by menotrophin.

CONCLUSIONS: Prescription of inappropriate drugs was observed in 4.2% of pregnancy. However, assessment of individual cases using information available in the claims data revealed that most of their use had adequate reasons. The prevalence of prescription drug use among our study population provided a real-world evidence on drug utilization pattern of pregnant women in Korea.