New Study: Tetracycline Use in First Trimester Shows No Birth Defect Risk for Pregnant Women

New Study: Tetracycline Use in First Trimester Shows No Birth Defect Risk for Pregnant Women

November 15, 2024 Catherine Williams - Chief Editor Health

Exposure to tetracycline antibiotics in early pregnancy does not increase the risk of major congenital malformations (MCMs), according to a study published in JAMA Network Open. Researchers analyzed data from Swedish health and population registries for children born between July 1, 2006, and December 31, 2018. The study focused on comparing MCMs, such as heart defects and cleft lips, between infants exposed to tetracyclines and those not exposed.

Tetracyclines, commonly prescribed antibiotics, are not recommended after the first trimester due to potential risks like bone growth issues and tooth discoloration. Researchers from Karolinska Institutet aimed to determine if these concerns also apply to the first trimester.

The study included over 1.2 million children and identified 6,341 infants (0.5%) exposed to tetracyclines during the first trimester, mainly doxycycline (78.2%). They compared these infants to 63,316 unexposed infants using propensity-score matching.

Of the tetracycline-exposed infants, 252 were diagnosed with any MCM, compared to 2,454 unexposed infants. The prevalence of MCMs was similar between both groups—39.75 cases per 1,000 for exposed infants versus 38.76 for unexposed. The risk of any MCM did not differ significantly (relative risk of 1.03). Specific risks for different tetracycline types were also similar.

The study is larger than previous research and includes new categories of MCMs. Researchers emphasize the need for even larger studies to confirm these findings for specific malformations.

In an editorial, Dr. John van den Anker highlighted the need for further research on tetracycline safety during pregnancy. He noted that pregnant individuals are often excluded from clinical trials, leading to a lack of knowledge about drug effects. He called for more clinical trials focusing on drug safety in pregnancy.

Health care providers should weigh the benefits of tetracycline treatment against potential risks for the fetus.