Risks of Birth Defects with Oral Fluconazole During Pregnancy

MedicalResearch.com Interview with:

Dr. Zhu

Yanmin Zhu, M.S., Ph.D.
Postdoctoral Research Fellow
Division of Pharmacoepidemiology and Pharmacoeconomics
Brigham and Women’s Hospital and Harvard Medical School 

MedicalResearch.com: What is the background for this study?

Response: Animal studies and case reports suggest a potential teratogenic effect associated with the use of high doses of fluconazole during pregnancy. The malformations reported in case reports have a distinct phenotype, including femoral bowing, thin ribs, cleft palate, and abnormal craniofacial ossification.

A few controlled studies have examined the risk of congenital malformations associated with the use of fluconazole during the first trimester, but findings are inconsistent.

MedicalResearch.com: What are the main findings? 

Response: This large cohort study confirmed an increase in the risk of musculoskeletal malformations if oral fluconazole is used during the first trimester, and refuted large increased risks of conotruncal malformations, oral clefts, and other specific types of malformations. A twofold increased risk of musculoskeletal malformations was identified in the highest cumulative dose group (>450 mg of fluconazole) during the first trimester

MedicalResearch.com: What should readers take away from your report?

Response: Oral fluconazole during the first trimester, especially prolonged treatment at higher than commonly used doses, should be prescribed with caution, and topical azoles should be considered as an alternative treatment. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: The large sample size of our study allowed us to examine the risk of rare malformations that have been suggested to be associated with fluconazole and specific dose groups. However, the number of cases was still limited for subgroups of musculoskeletal malformations, as well as specific malformations in high dose groups (e.g., conotruncal malformations). It would be great if future research can look further into this.

No disclosures to report.


Zhu Yanmin, Bateman Brian T, Gray Kathryn J, Hernandez-Diaz Sonia, Mogun Helen, Straub Loreen et al. Oral fluconazole use in the first trimester and risk of congenital malformations: population based cohort study BMJ 2020; 369 :m1494



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Last Updated on May 21, 2020 by Marie Benz MD FAAD