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Medication, Vaccine, and Folic Acid Use Among Pregnant Women in Belgium: Insights from the BELpREG Cohort

Year: 2026

Type: article

Abstract: ABSTRACT Background Safety data for most medications in pregnancy remain limited, yet pharmacological treatment is often necessary. Evidence on real‐world medication use in pregnancy including over‐the‐counter products and folic acid is scarce, especially in Belgium. Methods We conducted a drug utilization study using self‐reported data from BELpREG, a prospective, web‐based pregnancy registry established in November 2022. Pregnant individuals aged ≥ 18 years receiving healthcare in Belgium can enrol voluntarily at any stage in pregnancy and complete online questionnaires at enrolment and every four weeks until delivery. All participants with follow‐up beyond the first trimester were included, and trimester‐specific cohorts were constructed based on completion of questionnaires after each trimester. Data were extracted in July 2025. Results This study included 2096 participants, of whom 1767 were followed through trimester 2 and 1136 through trimester 3. Median gestational age at enrolment was 16 weeks. Prevalence estimates of medication use were 80.2% in the six months before conception, 85.8% in trimester 1, 92.0% in trimester 2, and 94.9% in trimester 3. The most common classes were analgesics, vaccines, antihistamines, antianemic preparations, and drugs for acid‐related disorders. Paracetamol was most frequently used (35.4% in trimester 1), typically short term (median 3 days), followed by doxylamine‐pyridoxine (26.7% in trimester 1). Folic acid supplementation was nearly universal, though only 59.9% met national guideline‐concordant criteria. Maternal vaccine uptake was substantial but incomplete, with 66.5% receiving pertussis, 43.7% influenza, and 24.4% COVID‐19 vaccination. Exposure to potentially inappropriate or teratogenic medications was rare. Conclusions Medication use during pregnancy in Belgium was nearly universal, with high use of paracetamol and doxylamine‐pyridoxine. Folic acid and vaccine uptake were substantial, but often not guideline‐concordant.

Source: Pharmacoepidemiology and Drug Safety

DOI: 10.1002/pds.70369