Patterns of pregnancy exposure to prescription FDA C, D and X drugs in a Canadian population.

OBJECTIVE: To examine prescription Food and Drug Administration (FDA) C, D and X drugs in general obstetric population.

STUDY DESIGN: Historical cohort study.

RESULT: A total of 18 575 women who gave a birth in Saskatchewan between January 1997 and December 2000 were included. Among them, 3604 (19.4%) received FDA C, D or X drugs at least once during pregnancy. The pregnancy exposure rates were 15.8, 5.2 and 3.9%, respectively, for category C, D and X drugs, and were 11.2, 7.3 and 8.2%, respectively, in the first, second and third trimesters. Salbutamol (albuterol), trimethoprim/sulfamethoxazole (co-trimoxazole), ibuprofen, naproxen and oral contraceptives were the most common C, D, X drugs used during pregnancy.

CONCLUSION: About one in every five women uses FDA C, D and X drugs at least once during pregnancy, and the most common prescription drugs in pregnancy are antiasthmatic, antibiotics, nonsteroid anti-inflammation drugs, antianxiety or antidepressants and oral contraceptives.