November 9, 2026

expert reaction to study finding use of common antibiotic doxycycline, in early pregnancy is linked to higher risk of pregnancy loss

Scientists react to study finding use of common antibiotic, doxycycline, in early pregnancy is linked to higher risk of pregnancy loss, as published in Annals of Internal Medicine*

From our friends at Australian SMC:

Prof Janna Morrison, Head of the Early Origins of Adult Health Research Group and Deputy Director for Health and Biomedical Innovation, Adelaide University, said:

“Many women require medication to manage health conditions during pregnancy; however, the effects of these medications on pregnancy and the developing fetus are understudied.

“Winterstein et al. approach this issue with a post-marketing analysis of large clinical datasets with a focus on antibiotics. Their research focuses on doxycycline antibiotics, which are commonly prescribed to women of reproductive age.

“Many studies would compare exposure to the medication of interest to non-exposure for any disease. A strength of this study is that they select two common indications for doxycycline – respiratory tract infection and acne – which makes the populations studied more similar. Each of these populations is then divided into those exposed to doxycycline or another antibiotic. Thus, the whole population is treated, and the data suggests that one antibiotic is associated with a lower risk of early pregnancy loss. This comparison is important because it provides the evidence required by clinicians to decide which antibiotic to prescribe to women of reproductive age or in early pregnancy.

“A key limitation of the study is that it only examined pregnancy loss. As a result, this study does not provide any evidence about the effect of either of the antibiotics studied in a pregnancy that continues to term or in the fetus. Having said this, the findings may help doctors make more informed decisions about which antibiotics to prescribe to pregnant women who require treatment for conditions such as respiratory infections or acne.

“More research is needed to understand whether antibiotics increase the risk of early pregnancy loss or affect the longer-term health of babies.”

* ‘Doxycycline and Risk for Pregnancy Loss. A Multi-database, Multi-indication Cohort Study’ by Almut G. Winterstein et al. was published in Annals of Internal Medicine at 22:00 UK time on Monday 9th November.

DOI: 10.7326/ANNALS-26-01647

Declared interests

Prof Janna Morrison: No declaration received.