Studies have demonstrated a relationship between subclinical hypothyroidism and obstetrics complications like preterm delivery, pre-eclampsia, placental abruption and stillbirth. Subclinical hypothyroidism and positive thyroperoxidase antibodies (TPOab) may increase the risk of early spontaneous abortion before 12 weeks of gestation. But there is not a consensus if the prevalence of TPOab should be treated before and during pregnancy when the level of thyroid-stimulating hormone (TSH) is normal.