Antibiotic Doxycycline Linked to Higher Pregnancy Loss Risk When Taken During First Trimester

A commonly prescribed antibiotic has been linked to a higher risk of pregnancy loss when taken during the first trimester.

Doxycycline is often used to treat acne and infections, including respiratory issues and sexually transmitted diseases such as chlamydia and syphilis, due to its broad-spectrum properties which enable it to target a wide variety of bacteria.

While doctors tend to avoid prescribing doxycycline during the second and third trimesters because of potential effects on fetal bone development, evidence on its safety during early pregnancy has been inconsistent and limited until now.

A new study published in Annals of Internal Medicine has shed more light on the risks associated with doxycycline use during the first trimester, suggesting a link between the antibiotic and increased risk of pregnancy loss.

A significant number of women prescribed doxycycline during their first trimester experienced complications in their pregnancies.

These women were among over 218,230 patients treated for respiratory tract infections and more than 6,630 treated for acne between conception and the end of the first trimester.

Of these women, about 4,385 filled a prescription for doxycycline during this time frame, while others received alternative antibiotics such as amoxicillin.

Women prescribed doxycycline for respiratory infections had a higher risk of pregnancy loss compared to those given amoxicillin.

The study's findings have sparked concerns about the safety of doxycycline during early pregnancy. Researchers looked at the link between various antibiotics and pregnancy loss within the first 12 weeks of gestation.

While it is unclear how doxycycline might contribute to pregnancy loss, animal studies suggest that the antibiotic could interfere with the development of the placenta. This could potentially make it harder for the placenta to support a growing fetus, noted Luke Grzeskowiak, an associate professor and clinical pharmacist at Flinders University in Australia.

The study's authors also hypothesize that doxycycline may have direct effects on the developing embryo. However, these explanations remain speculative, as the researchers have not established that either mechanism occurs in humans. The available data indicates that doxycycline exposure is just one potential risk factor among many for pregnancy loss.

"Pregnancy loss affects around one in four pregnancies and can happen for a multitude of reasons," Grzeskowiak noted. While taking doxycycline during early pregnancy may add to the risk, it does not necessarily mean that pregnancy loss will occur.

When prescribing doxycycline to women of reproductive age, doctors should consider the possibility of pregnancy, especially in those who are sexually active. This is because doxycycline may be prescribed before a pregnancy is recognized, and its use during early pregnancy has been linked to an increased risk of pregnancy loss.

Doctors should weigh the severity of the infection against the potential risks associated with doxycycline when making treatment decisions for women who could become pregnant. For less-serious infections, safer alternatives may be available, but in cases where doxycycline is still the best option, clinicians should consider a woman's pregnancy plans and medical history.

Ultimately, this new finding underscores the importance of careful consideration and informed decision-making when prescribing antibiotics to women of reproductive age.