Takeaway
Previously conducted meta-analyses have overestimated the risk of birth defects in offspring associated with antithyroid drug use during pregnancy because of bias.
Propylthiouracil (PTU) use during pregnancy is associated with a smaller risk of birth defects vs methimazole/carbimazole (MMI/CMZ) and may be similar in size as that observed with untreated hyperthyroidism.
Why this matters
Antithyroid drug use during pregnancy has been associated with an increased risk of birth defects in offspring.
However, uncertainty remains on the size of this risk and how it compares to untreated hyperthyroidism because of methodological limitations of previous studies.
Study design
7 cohort studies and 1 case-control study involving 6,212,322 pregnancies and 388,976 birth defects met eligibility criteria after a search on MEDLINE and EMBASE.
Funding: None.
Key results
Maternal antithyroid drug use during pregnancy was associated with an increased risk of birth defects in offspring compared with unexposed women:
PTU (adjusted risk ratio [aRR], 1.16; 95% CI, 1.08-1.25);
MMI/CMZ (aRR, 1.28; 95% CI, 1.06-1.54); and
exposure to both MMI/CMZ and PTU (aRR, 1.51; 95% CI, 1.16-1.97).
The risk of birth defects was significantly higher in unexposed women with hyperthyroidism vs unexposed women without hyperthyroidism (aRR, 1.15; 95% CI, 1.02-1.29).
The risk of any birth defect per 1000 was:
9.6 for unexposed hyperthyroidism;
10.2 for PTU;
17.8 for MMI/CMZ; and
32.5 for both MMI/CMZ and PTU.
Corresponding numbers for major birth defects per 1000 live births were 1.2, 1.3, 2.3, and 4.1.
Limitations
Risk of residual confounding.
This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.
© 2021 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Sarfaroj Khan. Antithyroid Drug Use During Pregnancy and Risk of Birth Defects in Offspring - Medscape - Apr 08, 2021.
Comments