Do Pregnant Women Report Use of Dispensed Medications?

TLDR

Surveillance of drug safety in pregnancy relies on administrative prescription registries, yet noncompliance is common because pregnant women fear fetotoxic side effects. This study aimed to estimate compliance with prescribed medication use during pregnancy by comparing prescription records from the North Jutland Prescription Database with self‑reported drug use in the Danish National Birth Cohort. Researchers identified all prescriptions dispensed to 2,041 DNBC participants in North Jutland and defined compliance as the likelihood that a woman reported using a drug in the DNBC after purchasing it. Compliance was low overall (43 %), with chronic‑disease drugs consistently reported but short‑term medications underreported, indicating that prescription data alone may miss exposure and lead to false‑negative risk assessments.

Abstract

Surveillance of drug safety in pregnancy often draws on administrative prescription registries. Noncompliance in the use of prescribed medication may be frequent among pregnant women owing to their fear of fetotoxic side effects. To estimate compliance in the use of prescription drugs dispensed during pregnancy, we compared prescription data from the North Jutland Prescription Database with information on drug use provided by pregnant women to the Danish National Birth Cohort (DNBC), which is a health interview survey. We used the North Jutland Prescription Database to identify all prescription drugs dispensed during pregnancy for the 2,041 women who were enrolled in the DNBC in the County of North Jutland, Denmark. Compliance was defined as the probability of reporting drug use in DNBC after purchasing a dispensed prescription drug. The overall compliance to drugs purchased within 120 days before the interview was 43% (95% confidence interval = 40–46). Drugs used for treating chronic diseases, for example, beta-blockers, insulin, thyroid hormones, and diuretic and antiepileptic drugs, were always reported to be used, but compliance was low for drugs used for local or short-term treatment such as antihistamines, antibiotics, antacids, nonsteroid anti-inflammatory drugs, and gynecologic drugs. Thus, for the latter drug groups the prescription database may provide an incomplete identification of exposure. Neither data source is unbiased regarding actual drug intake. Nevertheless, our results indicate that for some drug groups risk assessment studies based on prescription data may produce false negative results as a result of noncompliance.