Association between pregnancy and thyroid disorders is a frequent event. In case of maternal hyperthyroidism, strict guidelines relying mainly on foetal thyroid monitoring echographic scanning will allow in most cases the delivery of a healthy euthyroid newborn. Hypothyroidia, providing an adequate substitution has no significant impact on pregnancy, biological monitoring is the key of monitoring. Iodine deficiency is a matter of concern when considering neurodevelopmental outcome, however it is still an unsolved issue in France. However involvement of a multidisciplinary team is of good practice in most of the cases.