Drug use by pregnant women and comparable non-pregnant women in The Netherlands with reference to the Australian classification system.

OBJECTIVE: To describe drug use in pregnancy, and compare drug use of pregnant women with non-pregnant women with respect to possible teratogenicity. STUDY
DESIGN: A cross-sectional study based on pharmacy records from 1997 to 2001 was performed. Pregnant women and matched non-pregnant women (same physician and age) were identified. Prescriptions were set against the Australian risk classification.
RESULTS: Thirty-five percent of all prescriptions for non-pregnant women were safe in pregnancy (Australian classification A), in 14% the risk was unknown (B1, B2), 49% were potentially harmful drugs (B3, C, D, X), and in 3% no classification was available. For pregnant women these figures were 86, 3, 10 and 2%, respectively. In non-pregnant women the highest percentages of prescriptions for unsafe drugs were for psycholeptics (99% not classified as safe), psychoanaleptics (100%), anti-inflammatory/antirheumetic products (100%), antihistamines (94%), antacids/anti-ulcer drugs (81%), antiepileptics (100%), beta-blockers (100%), systemic antimycotics (100%), antiprotozoals (97%), diuretics (100%) and immunosuppressives (100%). In pregnant women this pattern was comparable, except for antihistamines (22%) and antacids/anti-ulcer drugs (3%).
CONCLUSION: We conclude that many drugs used by non-pregnant women should be avoided in pregnancy, and that pregnant women indeed do so. However, for some drug groups the available safe alternatives are limited.