The Surprising Link Between Antibiotic Usage and Miscarriage Risk

Could the type of antibiotic you take increase your risk of miscarriage? A new study raises some cautions and offers guidance.

TwitARegina/shutterstockPregnancy is an exciting—and trying—time. All the excitement of a baby on the way; all the worries about potential complications. (And don’t forget all the changes women can experience.) So here’s one worry you can cross off your list: If you end up with an infection, talk to your doctor about the type of antibiotic he or she wants to prescribe. A new study published in Canadian Medical Association Journal found an increased link of early miscarriage with many classes of common antibiotics.

Looking at data on more than 90,000 women from the Quebec Pregnancy Cohort between 1998 and 2009, a group of researchers from the Faculty of Pharmacy at the Université de Montréal found that expecting mothers treated with antibiotics in the classes of macrolides, quinolones, tetracyclines, sulfonamides and metronidazole had up to double the risk of suffering a miscarriage compared to women who didn’t take antibiotics or who took other types.

(By the way, don’t fall for these miscarriage myths.)

rui vale sousa/shutterstockBrian A. Levine, MD, an obstetrician and gynecologist and practice direction of CCRM New York, says it is important to recognize that not all antibiotics were included on the list of potential causative agents. (Two classes often used to treat UTIs in pregnant women, erythromycin and nitrofurantoin, were not associated with increased risk.) “Those that we use commonly in pregnancy every day were still deemed safe,” he says. “It is important to note that this was a retrospective chart review, and not the gold-standard study, a prospective randomized controlled trial (which would be possibly be unethical if any of these antibiotics did in fact cause untoward outcomes). With that said, the spontaneous miscarriage rate can be as high as 33 percent, so anything that impacts the natural miscarriage rate, is definitely worth investigating.”

Women’s health expert Sherry Ross, MD, an obstetrician and gynecologist and author of the woman’s guide, She-Ology, also has reassuring words for anyone who might be concerned about the results of this study. “The safer antibiotics in this study did not have an increase in miscarriages and would be the ones recommended for women trying to conceive or unsure of their pregnancy status,” she says. Ross doesn’t want the findings to stop pregnant women seeking treatment for UTIs. “Left untreated, UTIs can cause more damaging consequences than using acceptable antibiotics during pregnancy,” she explains. “Most importantly, make sure you discuss the pros and cons of UTI treatment options with your obstetrician, and discuss ways to avoid recurrent infections during the rest of the pregnancy. If you are trying to conceive you would want to make sure you are taking the antibiotics not associated with an increase in miscarriage risk.”

In other words, expectant moms: Don’t panic! If you have any concerns, speak to your doctor— and check out these other essential questions to ask before taking antibiotics.

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