In a world where many pregnancies arrive before they are expected, a common antibiotic taken in the first weeks has drawn a sober question into the open: whether a remedy meant to heal a cough or quiet acne might carry a quieter cost to a fragile beginning. A large American study of more than 220,000 pregnancies, published in Annals of Internal Medicine, found that doxycycline taken in the first trimester was associated with a higher rate of pregnancy loss than other treatments. Australian clinicians, who already keep this drug at arm's length during pregnancy, are now weighing that caution ag
Doxycycline in Early Pregnancy Linked to Higher Miscarriage Risk, US Study Finds
Potential pregnancy loss among women exposed to doxycycline in early pregnancy, according to the study's associated risk estimates.
Many pregnancies in Australia are unplanned
Mark
So what actually did the study find?
Mimi
Women who filled a doxycycline prescription in the first trimester had a 40 to 54 percent higher risk of pregnancy loss than those given amoxicillin for respiratory infections. Against macrolides it was 36 to 39 percent.
Mark
Why does the choice of comparison matter?
Mimi
Professor Morrison says everyone studied was being treated for the same kinds of conditions, so the groups are more alike than if you compared with untreated women.
Luke
Careful, though. Similar isn't identical. Dr Gallo says plainly this isn't evidence of cause and effect.
Mark
Is the result consistent across the data?
Mimi
For respiratory infections, yes, in both the commercial and Medicaid databases. Gallo says that makes the association more convincing.
Luke
But the acne finding is patchier. Higher risk in the commercial database, not in Medicaid. That's a split, not a clean confirmation.
Mark
Why would exposure happen at all, if it's usually avoided?
Mimi
Gallo notes many Australian pregnancies are unplanned, so a woman may take it before she knows.
Luke
And what's missing? The study only measured pregnancy loss. Nothing on full-term pregnancies or babies' health, and the source gives no absolute risk figures, only relative increases.
Mark
So what should clinicians take from it?
Mimi
Tremellen suggests avoiding doxycycline in women not using reliable contraception when alternatives are suitable.
El Pulso
- A common antibiotic filled in the first weeks of pregnancy, often before the pregnancy is even known, is linked to a higher risk of losing the pregnancy.
- The study's figures are stark: a 40 to 54 percent higher loss risk against amoxicillin, and 36 to 39 percent against macrolides.
- Clinicians are being asked to rethink antibiotic choices for women of reproductive age, balancing infection treatment against an uncertain but concerning risk.
- The findings appeared in both databases for respiratory infections, but only in commercial claims for acne, leaving researchers cautious about cause and effect.
- Further research on whether the link is causal, and what happens in pregnancies that continue, remains the open path forward.
In a world where many pregnancies arrive before they are expected, a common antibiotic taken in the first weeks has drawn a sober question into the open: whether a remedy meant to heal a cough or quiet acne might carry a quieter cost to a fragile beginning. A large American study of more than 220,000 pregnancies, published in Annals of Internal Medicine, found that doxycycline taken in the first trimester was associated with a higher rate of pregnancy loss than other treatments. Australian clinicians, who already keep this drug at arm's length during pregnancy, are now weighing that caution against the everyday need to treat infection, and they are doing so knowing that an association is not yet a proven cause.
A prescription for doxycycline, a widely used antibiotic, was filled in the first weeks of a pregnancy that many women do not yet know they carry. A new US study in Annals of Internal Medicine followed this moment through insurance records covering more than 220,000 pregnancies. Women who took doxycycline in the first trimester faced a higher risk of pregnancy loss than those given amoxicillin or macrolides, and the pattern held in the larger database for respiratory infections.
Australian experts responded with care. Dr Linda Gallo noted that unplanned pregnancies mean exposure still happens, and that the finding is a warning to weigh risk against benefit. Professor Kelton Tremellen urged doctors to consider avoiding doxycycline in women of child-bearing age not using reliable contraception where alternatives exist, pointing to earlier concerns about early placental development.
Professor Janna Morrison praised the study's design, which compared treated women with other treated women rather than with the untreated, giving clinicians a fairer basis for choosing between antibiotics. She also named its limits: it tracked only pregnancy loss, not full-term outcomes or the health of the fetus. The authors hope their data will guide treatment decisions during pregnancy, but whether the link is causal, and what follows for pregnancies that continue, remain unanswered.
A prescription for a common antibiotic, filled in the first weeks of a pregnancy that a woman may not yet know about, is at the center of a new US study. Published in Annals of Internal Medicine, the research found that women who filled a doxycycline prescription during the first trimester had a higher risk of pregnancy loss than women treated with other antibiotics.
The numbers are specific. For respiratory infections, doxycycline was linked to a 40 to 54 percent higher risk of pregnancy loss than amoxicillin. Compared with macrolide antibiotics, the excess risk was 36 to 39 percent. Doxycycline is prescribed for respiratory tract infections and acne, and it ranks among the four most frequently dispensed antibiotics in Australia.
The US researchers drew on insurance claims covering more than 220,000 pregnancies, using both commercial and Medicaid databases. They compared women who filled doxycycline prescriptions in the first trimester with women given alternatives: amoxicillin or a macrolide for respiratory infections, and topical clindamycin for acne.
The pattern was not uniform. Among women with respiratory infections, doxycycline users had a higher risk of pregnancy loss in both databases. Among women with acne, the higher risk appeared in the commercial claims database but not in Medicaid.
Australian experts, writing in response, noted that doxycycline is generally avoided in pregnancy because of known adverse effects on foetal development. Dr Linda Gallo of the University of the Sunshine Coast's School of Health said exposure can still happen, because many pregnancies in Australia are unplanned. She said the finding appearing in both databases makes the association more convincing, but stressed the study is not evidence of cause and effect. In her words, it is an important warning to balance potential risk against benefit.
Professor Kelton Tremellen, a gynaecologist and reproductive medicine professor at Flinders University, said the results add to earlier concerns that doxycycline can interfere with biological processes essential for early placental development. His advice: doctors should consider avoiding it in women of child-bearing age who are not using reliable contraception, where suitable alternatives exist.
Professor Janna Morrison of Adelaide University pointed to the study's design as a strength. Many medication studies compare exposed women with unexposed women, whatever their condition. This one chose two common reasons for prescribing doxycycline, respiratory infection and acne, and then split each group by which antibiotic was used. Everyone in the comparison was therefore being treated, which she said gives clinicians the evidence needed to choose between antibiotics for women of reproductive age or in early pregnancy.
Morrison also named a limitation: the study looked only at pregnancy loss, not at full-term pregnancies or the foetus. She said more research is needed to learn whether antibiotics raise the risk of early loss or affect babies' longer-term health. The study authors say their results add data to inform recommendations on treating infections, and on post-exposure prophylaxis, during pregnancy. The open questions are whether the link is causal and what happens in pregnancies that continue.
Citas Notables
The findings serve as an important warning to balance potential risk with benefits, though the study is not evidence of cause and effect.— Dr Linda Gallo, University of the Sunshine Coast
Doctors should consider avoiding doxycycline in women of child-bearing age not using reliable contraception, where suitable alternatives are available.— Professor Kelton Tremellen, Flinders University
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