Endocrine Abstracts

Aim: Hyperthyroidism can affect pregnancy outcomes based on activity of the disease, ongoing use of anti-thyroid drugs (ATD) and TSH receptor antibody (TRAB) positivity. The aim of our audit was to analyse the outcomes of fetal monitoring in pregnant women with previous or current history of active hyperthyroidism

Methods: The data on all patients with hyperthyroidism and pregnancy over 3 years was collected. The local guidelines recommend TRAB check at 20 weeks. If TRAB + and/or patient continuing on ATD into third trimester, fetal medicine scan(FM Scan), serial growth scans in third trimester and a neonatal alert for a new-born review were arranged.

Results: N = 56. This included women with active Graves’ (n = 34); previous hyperthyroidism currently in remission (n = 15) and post radio-iodine or thyroidectomy induced hypothyroidism(n = 7). Of the Graves’ patient, 19 required ATD continuing into 3^rd trimester, with the rest withdrawing ATD during the course of early pregnancy

TRAB ±

N = 31; FM Scan normal in 30 patients-1 patient had an abnormal scan (hydronephrosis) which was likely unrelated to the thyroid disease. Serial growth scans were done in 26/31 women– 20 normal; 3 had large for gestational age (1 on thyroxine, 2 were euthyroid on no ATD) – one had normal birth weight, one was born preterm at 30 weeks, other baby was 3.7 kg at birth. 3 had small for gestational age (1 on thyroxine, 2 were euthyroid on no ATD)- one had twin pregnancy, one had pre-eclampsia with known hypertension and the third baby was well after delivery. On looking at the women who did not have growth scans (due to recent change in local guidelines), 4 had only weakly + TRAB and 1 had premature rupture of membranes attributed to likely placental issues.

Patients on ATD

N = 19; FM Scan was normal in all 19 women and were normal. Serial growth scans (n = 18) were normal in 16/18 women-2 had small for gestational age which is not consistent with ATD use and both had normal TFT. (1 patient who did not have the growth scan was the patient with premature rupture of membranes).

Conclusion: The study shows generally good outcomes for patients with hyperthyroidism. Serial growth scans can be used as a preliminary screening to guide further monitoring during pregnancy to monitor for TRAB or ATD or active Graves’ related impact to pregnancy. Fetal medicine scans may be reserved for patients with high TRAB as they have generally been normal.