To explore the significance of hypothyroidism and subclinical hypothyroidism screening in pregnancy. A total of 278 pregnant women were divided into three groups of clinical hypothyroidism (n=36), subclinical hypothyroidism (n=103) and normal control (n=139). Their clinical profiles, pregnancy outcomes and fetal status were analyzed. The incidences of abortion (11.1%), premature delivery (8.3%), preeclampsia (11.1%), gestational diabetes mellitus (GDM, 13.9%), anemia (16.7%), fetal distress (8.3%) and fetal growth retardation (FGR, 5.6%) in clinical hypothyroidism group were higher than those in normal control group (2.9%, 1.4%, 1.4%, 2.2%, 4.3%, 0.0% and 3.6%). And the differences were statistically significant (P<0.05). The incidence of adverse pregnancy had a significant correlation with hypothyroidism in pregnant women. Therefore screening of thyroid functions is essential for improving pregnancy outcomes of pregnant women with hypothyroidism.