Birth defects linked to antithyroid drug treatment in pregnancy

Birth defects linked to antithyroid drug treatment in pregnancy have for a long time been known to exist. A recent Danish register-based cohort study has assessed the degree of association of antithyroid drugs (ATD), such as methimazole (MMI) / carbimazole (CMZ) and propylthiouracil (PTU), and the spectrum of disease.

The prevalence of birth defects appears to be high in children exposed to ATD in early pregnancy. Both MMI/CMZ and PTU are associated with an increased odds ratio of birth defects, with an odds ratio (OR) approximating 2. The commonest defects in MMI/CMZ-exposed children seem to appear with an adjusted OR ~20 when combined 2.

MMI/CMZ-exposed children may commonly develop:

Both MMI/CMZ and PTU have been shown to be associated with urinary system malformation. Moreover, PTU may predominantly cause malformations in the face and neck region.

Hyperthyroidism in pregnant women is a known source of a variety of maternal and fetal complications, necessitating the use of antithyroid drug treatment (ATD) in pregnancy to control maternal hormone levels.

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Article information

rID: 28597
System: Paediatrics
Synonyms or Alternate Spellings:
  • ATD teratogenity
  • Early pregnancy antithyroid effects
  • ATD embryopathy
  • Antithyroid embryopathy

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