Use of Carbimazole, Thiamazole and Propylthiouracil during pregnancy in Germany


The treatment of Graves' disease in girls and women of childbearing age is particularly challenging due to the potential occurrence of pregnancy. Failure to treat the hyperthyroidism associated with the disease during pregnancy is associated with risks for the pregnancy, the health of the child (spontaneous abortions, premature birth, stillbirth, low birth weight), and the health of the mother (thyrotoxic crisis). There is also an increased risk of congenital malformations associated with drug treatment of the disease with thiamazole (TMZ) and its prodrug carbimazole (CMZ) during pregnancy. The third drug available for treatment, propylthiouracil (PTU), has not been clearly shown to cause malformations, but PTU should not be used routinely because of the increased risk of acute liver failure.

The Federal Institute for Drugs and Medical Devices (BfArM) issued the following recommendations regarding thyrostatic therapy during pregnancy:
• When considering pregnancy under thyrostatic therapy, patients treated with TMZ or CMZ should
be switched to PTU prior to conception following an individual risk-benefit assessment, since the
currently available data indicate at the most a slightly increased malformation potential of PTU.
• The use of TMZ or CMZ in the first trimester of pregnancy should be limited to cases of intolerance
to PTU.
• Switching from PTU to TMZ or CMZ after the sensitive phase of organogenesis has been
completed may be considered on an individual benefit-risk basis to reduce the risk of maternal liver

The primary objective of this project, which is funded by BfArM, is to investigate how the measures and recommendations described above are reflected in real-world healthcare practice in Germany. Based on the data from the health insurance providers contained in GePaRD, the following questions will be investigated:
• How frequently are drugs containing CMZ, TMZ, and PTU used in girls or women of childbearing
• How frequently does pregnancy occur during therapy with CMZ, TMZ or PTU?
• What are the outcomes of these pregnancies (including possible complications)? Which
prescription patterns occur during pregnancy?

Funding period

Begin:   December 2020
End:   April 2022


  • Federal Institute for Drugs and Medical Devices


Dr. rer. medic. Tania Schink