Maternal thyroid function, use of antithyroid drugs in early pregnancy and birth defects

Stine Linding Andersen, Louise Knøsgaard, Jørn Olsen, Peter Vestergaard, Stig Andersen
Journal of Clinical Endocrinology and Metabolism 2019 August 13

CONTEXT: Antithyroid drug (ATD) therapy in early pregnancy is associated with birth defects, but more data are needed to substantiate the risk associated with different types of ATD. Furthermore, the role of abnormal maternal thyroid function per se remains unclarified.

OBJECTIVE: To evaluate the risk of birth defects associated with the use of ATD in an extended nationwide cohort and the role of abnormal maternal thyroid function in birth cohorts including stored maternal blood samples from the early pregnancy.

PARTICIPANTS: Danish pregnant women and their live-born children including 1,242,353 children from a Nationwide Register-Based Cohort (NRBC), 1997-2016; 8,803 children from the Danish National Birth Cohort (DNBC), 1997-2003; and 14,483 children from the North Denmark Region Pregnancy Cohort (NDRPC), 2011-2015.

MAIN OUTCOME MEASURES: Birth defects diagnosed before two years of age.

RESULTS: In the NRBC, altogether 2,718 (0.2%) children had been exposed to ATD in early pregnancy. The overall frequency of birth defects was 6.7% (95% confidence interval (CI): 6.7-6.8%) in non-exposed children, and higher after exposure to Methimazole/Carbimazole (9.6% (95% CI: 8.2-11.2%)) and Propylthiouracil (8.3% (6.7-10.3%). On the other hand, the frequency of maternal thyroid dysfunction in early pregnancy was similar in the random cohort and in cases of birth defect in the DNBC (12.4 vs. 12.6%, p=0.8) and the NDRPC (15.1 vs. 15.4%, p=0.8).

CONCLUSIONS: Results corroborate an increased risk of birth defects associated with the use of ATD in early pregnancy, and suggest that abnormal maternal thyroid function is not a major risk factor for birth defects.


You need to log in or sign up for an account to be able to comment.

No comments yet, be the first to post one!

Related Papers

Available on the App Store

Available on the Play Store
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"