Endocrine Abstracts

Introduction: Thyroid dysfunction and thyroid autoimmunity (TAI) have been associated with adverse pregnancy outcomes for both the mother and the fetus. The aim of this study was to describe fetal growth parameters of pregnancies complicated with thyroid diseases/TAI and to construct predictive models for their outcome.

Methods: The study included 196 consecutive singleton pregnancies in women with thyroid diseases, during the period 2007–2010. A cohort of 809 singleton pregnancies in euthyroid women without TAI was used as fetal growth control. The main metabolic parameters evaluated were: thyroid hormones (TSH, fT₄), thyroid auto-antibodies (TPOAb, TgAb, TSI) and doses of levothyroxine (LT₄) and antithyroid medications for women with hypothryroidism and hyperthyroidism respectively. The main fetal growth parameters evaluated were: estimated fetal weight (EFW), head circumference (HC) and abdominal circumference (AC). Predictive models were constructed for pregnancies complicated with hypothyroidism.

Results: In the study population, 16% of women were euthyroid, having either TAI or nodular thyroid disease, 19% hyperthyroid and 65% hypothyroid. Of the studied pregnancies, 88% resulted in live birth, 10% in spontaneous abortion, 1% in iatrogenic abortion and 1% in intrauterine death. Maternal complications included pregnancy-induced hypertension, pre-eclampsia, hyperemesis gravidarum, placental abruption and poly-hydramnion/oligoamnion. Neonatal complications included jaundice, tachypnoea, respiratory distress syndrome and hypothyroidism. Fetuses of mothers with hypothyroidism had increased AC in comparison to fetuses of normal pregnancies but did not differ with respect to EFW or HC. In pregnancies complicated by hypothyroidism, thyroid auto-antibodies or serum TSH did not predict neither pregnancy outcome nor occurrence of maternal or neonatal complications.

Conclusions: The increment in fetal AC in pregnancies complicated by hypothyroidism needs to be confirmed in further prospective studies. The outcome of pregnancies complicated by thyroid dysfunction does not seem to be predicted by hormonal or ultrasonographic parameters.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.