Congenital iodine-deficiency
ICD-10 E00 · ICD-11 5A00.04

Treatment of Congenital Iodine-Deficiency in Women with Congenital Hypothyroidism Planning Pregnancy

Clinical Scenario

This protocol addresses women with congenital hypothyroidism (CH) who are planning pregnancy or are currently pregnant. In this population, thyroid hormone requirements shift substantially, and management of congenital iodine-deficiency must be adapted accordingly.

Women in this situation should receive counselling about the anticipated change in LT4 requirements during gestation, ideally before conception.

Treatment Approach (Partial Overview)

Management centres on optimising levothyroxine (LT4) therapy, with a dose adjustment expected during pregnancy for most women, combined with attention to adequate daily iodine intake. The complete structured regimen — including the specific adjustments, monitoring schedule, and decision algorithm — is available via the protocol link below.

Clinical Targets

The primary goal in LT4-treated women is maintaining serum TSH below 2.5 mU/L throughout gestation. In pregnant women with central CH, free T4 (fT4) is targeted above the mean/median value of the trimester-specific reference interval.

Instant Access to Structured Evidence-Based Regimens

References

  1. In women with CH who are planning pregnancy, we strongly recommend optimization of LT4 treatment; in addition, these women should be counseled regarding the higher need for LT4 during pregnancy.
  2. During pregnancy, TH requirement increases and most LT4-treated women require a dose increase up to 30%.
  3. fT4 (or total T4) and TSH levels should be monitored every 4 to 6 weeks during pregnancy, aiming at TSH concentrations in accordance with current guidelines on treatment of hypothyroidism during pregnancy, that is, <2.5 mU/L throughout gestation in patients treated with LT4.
  4. In pregnant women with central CH, the LT4 doses should be increased aiming at an fT4 concentration above the mean/median value of the trimester specific reference interval.

DOI: 10.1089/thy.2020.0333

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