Infants of hypothyroid mothers- are postnatal Thyroid Function Tests necessary? A Retrospective Study in a Regional...

Area of Science:

• Pediatrics
• Endocrinology
• Neonatal Screening

Background:

• Congenital hypothyroidism is a significant, yet preventable, cause of intellectual disability.
• Early detection and treatment are crucial to prevent long-term developmental issues.
• National newborn bloodspot screening programs aim to identify affected infants shortly after birth.

Purpose of the Study:

• To evaluate the efficacy of an additional thyroid function test (TFT) between 10-14 days of life for infants born to mothers with known hypothyroidism.
• To determine if this supplemental screening identifies cases missed by the national newborn screening program.
• To assess the necessity of routine 10-14 day TFTs in this specific infant population.

Main Methods:

• Infants born to mothers with hypothyroidism between 2012-2014 were identified via the Paediatric Ward attenders log.
• Thyroid Function Tests (TFTs) data were collected for these infants.
• Maternal Anti-Thyroid Peroxidase (Anti-TPO) antibody levels were also recorded.

Main Results:

• Out of 121 infants included, none presented with a significantly elevated Thyroid Stimulating Hormone (TSH) requiring treatment.
• Forty infants underwent repeat TFTs, with no cases requiring thyroxine treatment identified.
• The study found no additional congenital hypothyroidism cases requiring treatment beyond the national screening.

Conclusions:

• The current national newborn screening program is effective in detecting congenital hypothyroidism.
• Routine thyroid function testing at 10-14 days of life in infants of hypothyroid mothers is not recommended.
• Discontinuation of the practice of routine 10-14 day TFTs in this cohort is advised.