Introduction: Hypothyroidism including its subclinical form affects about 3% of pregnant women. It has adverse effects on pregnancy and the fetus with evidence of impaired intellectual development. The fetal thyroid gland reaches maturity by 12 weeks of gestation. Hence in the first trimester of pregnancy the fetus is dependant on the mother and optimising serum levels of thyroxine is important.
Methods: we conducted a retrospective audit of the management of hypothyroid patients attending our combined endocrinology/antenatal clinic between June 2010 & Dec 2010 against the American Endocrine Society guidelines. We assessed if thyroid function tests (TFT) were checked and target TSH achieved preconception, in the first, second & third trimesters and postpartum.
Results: 46 patients were identified. The mean age was 32 ± 3.2 years. In 27% of cases there was no record of preconception TFT. The mean TSH was 2.69 mIU/l and 48% had a level < 2.5 mIU/l. Only 50% of patients had their first antenatal visit at < 12 weeks of gestation with 59% of them having a TSH of <2.5 mIU/L. In the first trimester mean TSH was 3.03 mIU/l with 37% <2.5 mIU/l. In the second trimester mean TSH was 1.84 mIU/l with 75% <3 mIU/l and by the third trimester the mean TSH was 2.06 with 88% <3 mIU/l. Postpartum TFT were done within 6 weeks in 23% of patients & afterwards in 42% with 55% having low TSH and a further 13% suppressed TSH.
Conclusion: The results indicate suboptimal management of patients in early pregnancy and the postpartum period. Education of primary care clinicians to ensure optimal TSH levels preconception and in early pregnancy is important. Furthermore local guidelines to screen high risk patients and check early postpartum TFT are needed
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.