Endocrine Abstracts

Introduction: Graves’ hyperthyroidism affects 0.2–2% of women and 1–5% of infants born to these mothers will be symptomatic. Neonatal thyrotoxicosis is a potentially life-threatening condition and infants are currently monitored in hospital till day 4 of life. Graves’ disease is caused by TSH-receptor antibodies (TRAb) which can cross from the maternal to the foetal circulation where they may stimulate the developing thyroid gland causing neonatal thyrotoxicosis. Infants born to mothers with a history of thyrotoxicosis can be classified as high or low risk based on maternal TRAb levels in pregnancy.

Methods: Infants born at Nottingham City and Queen’s Medical Centre who had thyroid function tests (TFTs) in the first week of life due to maternal thyrotoxicosis were included in this retrospective audit. Maternal and infant notes were reviewed to ascertain the postnatal length of stay, day of thyroid function testing and TRAb levels, if checked in pregnancy.

Results: 57 infants were identified (56% male). Five had a maternal history of hypothyroidism and should not have required delayed discharge or TFT checks. Median length of stay was 4 days (total 302 days); 14% were discharged before day 4 and 21% were discharged after day 5. TFTs were checked on day 4–5 in 96%. TFTs were rechecked on days 9–11 in 28% (day 7–8: 21%; day ≥12: 21%; not done: 30%). No infants had a diagnosis of neonatal thyrotoxicosis. Thirty-nine (68%) mothers had TRAbs checked during pregnancy of which 4 (10%) were <1.0, 15% were 1–1.9, 8% were 2–2.9 and 18% were >3.0.

Conclusion: We found a history of maternal thyrotoxicosis in 0.5% live births, consistent with previous reports and, when checked, 10% of maternal TRAb levels were <. Regular antenatal checking of TRAb levels, along with a new guideline and improved training, will aim to reduce mismanagement of infants born to mothers with hypothyroidism and increase the number of families offered a routine discharge. This will represent an estimated saving of £15 000 pa, with further savings if higher TRAb levels were accepted, and will benefit families.