Two readers ask about taking antibiotics while pregnant.
Current research suggests no significant difference in circulating hormones when a woman is taking broad-spectrum antibiotics (other than rifampin) (Item 117-17). The recommendation is that a woman with vomiting, diarrhea, or forgetfulness use a backup method for the duration of antibiotic use (Hatcher RA, Nelson AL, Zieman M, et al. Managing Contraception. Tiger, Ga.: Bridging the Gap Foundation; 2004:103).
—Barbara C. Klein, WHNP, Wilmington, N.C.

Item 117-17 perpetuates the myth of antibiotic interference with hormonal contraceptives. With the exception of anti-tuberculosis agents, there is no evidence to support this claim. According to the AMA, none of the controlled studies to date demonstrate interaction between antibiotics and oral contraceptives (OCs) (Arch Fam Med. 2000;9:81-82). A review of the literature comes to the same conclusion (J Am Acad Dermatol. 2002;46:917-923). This review goes on to state that the current position of the American College of Obstetricians and Gynecologists is that “backup contraception is not necessary for women who reliably use OCs during antibiotic use.”
—Amy Cutting, APRN, FNP-C, Salt Lake City

I respectfully refer both readers to the article cited in my original response (Martin KA, Barbieri RL. Overview of the use of estrogen progestin contraceptives. In: Rose BD, ed. UpToDate. Wellesley, Mass.: UpToDate; 2008). The authors state that “a nonhormonal contraceptive method is recommended for women taking rifampin… Backup contraception is [also] advised for those receiving tetracyclines, penicillins, or cephalosporins.”
Whether clinicians heed this advice is a matter of choice. As in all areas of medicine, individual practice is defined as much by personal experience and opinion as it is by science. And this is not entirely avoidable because, despite what we might wish, evidence-based medicine remains more an ideal than a reality: We simply do not have double-blind, placebo-controlled studies to defend or refute everything we do.
—Reuben W. Zimmerman, PA-C

Continue Reading