Objective To study the poor pregnancy outcomes of patients with intrauterine hematoma in the second and third trimesters, and discuss the risk factors. Methods We analyzed the clinical data of 477 patients who underwent routine examination in our hospital from January 2010 to June 2016 and classified them into normal pregnancy (NP) group and adverse pregnancy (AP) group according to their pregnancy outcomes. Results Gestational age at first detection of hematoma of AP group(23.22±6.87 weeks) was more than NP group (16.11±4.76 weeks)(P<0.001). The volumes of hematoma during the first detection were significantly different between the two groups (P=0.001).The average hematoma volume were 8.01(2.22-28.67)(NP),13.05(3.54-26.34)mL(AP)respectively. However, the hematoma volumes recorded in the second B-ultrasound examination were not significantly different between the two groups (P=0.230). In the AP group, the incidence of retroplacental hematoma (53.4%) was significantly higher than in the NP group (24.2%), while the incidence of subchorionic hematoma (44.0%) was significantly lower than in the NP group (73.8%)(P<0.001). The incidence of palpable contractions in the AP group (62.8%) was significantly higher than in the NP group (12.1%), P<0.001. However, the incidence of vaginal bleeding was similar (P=0.407). Conclusion Intrauterine hematoma in the second and third trimester may lead to adverse pregnancy outcomes. Risk factors for poor pregnancy outcomes are included gestational age at first diagnosis, acute and large intrauterine bleeding, location of hematoma and accompanying contraction.