The teratogenic risk of trimethoprim-sulfonamides: a population based case-control study

Reprod Toxicol. 2001 Nov-Dec;15(6):637-46. doi: 10.1016/s0890-6238(01)00178-2.


Objective: To study human teratogenic potential of two trimethoprim-sulfonamide combinations: trimethoprim-sulfamethoxazole (cotrimoxazole) and trimethoprim-sulfamethazine during pregnancy. These agents have antifolate effects and other antifolate agents can induce multiple congenital abnormalities, neural-tube defects, cardiovascular, and other malformations in animal experiments and in humans.

Design: Pair analysis of cases with congenital abnormalities and matched healthy controls in the large population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996.

Participants: 38,151 pregnant women who had newborn infants without any congenital abnormalities (control group) and 22,865 case pregnant women who had newborns or fetuses with congenital abnormalities.

Main outcome: Prevalence of drug use in matched case-control pairs to study the possible association with congenital abnormalities.

Results: In the case group 351 (1.5%) and in the control group 443 (1.2%) pregnant women were treated with cotrimoxazole (crude OR 1.3 with 95% CI 1.1-1.5). In addition 45 (0.2%) case and 39 (0.1%) control pregnant women had trimethoprim-sulfamethazine treatment (crude OR 1.9 with 95% CI 1.3-3.0). A higher rate of multiple congenital abnormalities (including mainly urinary tract and cardiovascular abnormalities) was found in case infants born to mothers with cotrimoxazole treatment during the second-third months of pregnancy. In addition, a higher rate of cardiovascular malformations occurred in cases born to mothers with cotrimoxazole treatment and trimethoprim-sulfamethazine treatment during the second-third months of pregnancy, respectively.

Conclusion: Treatment with cotrimoxazole during pregnancy may increase the risk of cardiovascular malformations, and particularly multiple congenital abnormalities including defects of the urinary tract and cardiovascular system. A higher rate of cardiovascular malformations was also found after treatment with trimethoprim-sulfamethazine in the second-third months of pregnancy.

MeSH terms

  • Abnormalities, Drug-Induced / epidemiology*
  • Adult
  • Anti-Infective Agents, Urinary / adverse effects*
  • Case-Control Studies
  • Drug Combinations
  • Female
  • Gestational Age
  • Humans
  • Hungary / epidemiology
  • Infant, Newborn
  • Population Surveillance
  • Pregnancy
  • Pregnancy Outcome
  • Registries
  • Risk Assessment
  • Risk Factors
  • Sulfamethazine / adverse effects*
  • Trimethoprim, Sulfamethoxazole Drug Combination / adverse effects*


  • Anti-Infective Agents, Urinary
  • Drug Combinations
  • Sulfamethazine
  • Trimethoprim, Sulfamethoxazole Drug Combination