Inadequately controlled hypothyroidism in pregnant women is associated with mental retardation and learning difficulties in children. Some forms of hyperthyroidism put a foetus at risk of growing slowly and being at risk for stillbirth . Treatment for hyperthyroidism needs to be monitored carefully to decrease the risk of the foetus developing hypothyroidism . Metabolism changes in pregnancy sometimes cause a need to change the dose of thyroid medications. The blood tests used to evaluate thyroid function normally change during a pregnancy and need special interpretations.
Some thyroid problems can get worse in the postpartum period .