Foetal hyperthyroidism is most commonly seen during the 3rd trimester. In symptomatic cases, foetal hyperthyroidism may be treated by administration of antithyroid drugs (ATD) to the mother.

Neonatal signs and symptoms may be present at birth or delayed for several days, particularly in the presence of maternal ATD treatment.

It is reported that >95% of infants who develop symptoms do so between 1 and 29 days of life with the majority being diagnosed in the first 2 weeks of life.

Recommendation

All high risk babies should be examined on Day 1 of life, day 3-5 and day 10-14, looking for evidence of hyperthyroidism (Table 1).Babies should be reviewed more frequently if there is any clinical concern.
Criteria for considering admission to hospital:

• need for -Blocker
• heart failure, arrhythmia
• haemodynamic instability
• tracheal compression secondary to goitre
• failure to thrive.