Antibiotics Linked To Miscarriages | 5 Drugs Identified

From the moment we find out we’re pregnant, we do our very best to make the safest choices we can.

Our midwives, our doctors, and researchers contribute to helping us make wise and safe choices when it comes to using medications during pregnancy.

Being pregnant for nine months means we may experience illness and infections simply because it’s a long period of time.

Some Antibiotics Linked To Miscarriages

At times, medications like antibiotics, are used in hope of making us well and protecting our baby.

New research, published in the Canadian Medical Association Journal, found a link between some antibiotics and miscarriage.

What Antibiotics Linked With Miscarriage?

The researchers found the following antibiotics were related with higher rates of pregnancy loss:

1. tetracyclines,
2. macrolides,
3. quinolones,
4. metronidazole and,
5. sulfonamides

Due to concerns about birth defects, doctors don’t prescribe tetracyclines during pregnancy.

Sometimes, however, women are prescribed medications prior to knowing they’re pregnant. Quinolones are also commonly avoided during pregnancy.

Suflonamides are commonly used to treat urinary tract infections as well as ear and eye infections, and bronchitis.

Macrolides and metronidazole are also used when stronger antibiotics are needed for some common infections.

Are There Any Antibiotics That Are Safe During Pregnancy?

While all medications have potential risks and side effects, it’s important to remember that untreated infections also have risks. Fortunately, there are antibiotics which are safe and not associated with higher rates of pregnancy loss.

Lead researcher and member of the Faculty of Pharmacy at the Université de Montréal, Dr. Anick Bérard wrote: “It is reassuring to see that first-line treatments and antibiotics that are the most used in the population (penicillin, cephalosporin) were not associated with an increased risk of miscarriage.”

Nitrofurantoin, penicillin, cephalosporin and erythromycin were not associated with an increased risk of pregnancy loss. These antibiotics are used for many common infections such as urinary tract infections, respiratory infections, etc.

Erythromicin is also prescribed to treat some sexually transmitted infections and is used in pregnant women to prevent Group B streptococcal infection in newborns.

While there are risks with many antibiotics, the research did find that the most commonly prescribed first-line medications are safe for use in pregnant women.

Is The Risk Of Loss High With Antibiotic Use?

The risk of early pregnancy loss in the general population is higher than many people realise. Because spontaneous early pregnancy loss can happen apart from risk factors, it’s important that multiple studies be sure of causality. If the same findings show in multiple studies, it helps researchers to assess correlation and risk level.

A 2013 Danish study found a link between clarithromycin and miscarriage. While that study varied from this one, both found a connection between certain antibiotics and miscarriage.

Bérard and her team compared medical record data from 8,702 pregnancies that ended in miscarriage at an average of 14 weeks into the pregnancy with 87,020 that did not end in miscarriage.

Of the women that miscarried, 16.4% had taken antibiotics early in pregnancy. Of the women who didn’t miscarry, 12.6% had taken antibiotics.

In general, a woman who doesn’t take antibiotics during pregnancy has around a 6-7% risk of miscarriage. In this study, women who took certain antibiotics in early pregnancy had an increased risk of 9-10%.

Overall, the risk still remains small. However, there are safe antibiotics available which would likely work in many situations.

Are There Ever Times These Antibiotics Should Be Prescribed During Pregnancy?

This study looked at antibiotic use only during early pregnancy. It also confirmed current guidelines which showed certain medications shouldn’t be prescribed during pregnancy.

The study confirmed the need to treat infections. In fact, while many other risk factors were accounted for (e.g., living situations and age) Bérard noted that the infections themselves could contribute to pregnancy loss, thus it could explain some of the increased risk.

“We also found that nitrofurantoin, mostly used to treat urinary tract infections, are actually decreasing the risk of miscarriage,” Bérard said.

Pregnant women should discuss any infection with their midwife or doctor and discuss the benefits and risks of each potential antibiotic. There are safe antibiotics so if one linked to miscarriage is recommended you can discuss the option of using another, or the benefit versus risk as the overall risk is still low.