Objective To explore the outcomes and adverse effects of isolated hypothyroxinemia in pregnant women. Methods 112 cases of diagnosed isolated hypothyroxinemia (observation group) and 112 euthyroid pregnant women (control group) in pregnancy period were selected. The thyroid function indexes were determined and the pregnancy outcomes were analyzed. Results There were no statistical differences on pregnancy outcomes related to age, previous reproductive history, history of diabetes mellitus, HbA1C, history of thyroid disease between two groups. There were no statistical differences in serum FT3 and TSH levels between two groups. The mean serum FT4 level in observation and control group were 9.3±0.9 μg/L and 13.9±0.8 μg/L respectively and with significant differences (P<0.05). There were no abortion, preeclampsia, premature birth observed in both groups during the pregnancy. Conclusion The isolated hypothyroxinemia has no any adverse effects on pregnancy outcome.