【Objective】 To study the effect of ovarian endometrioma on pregnancy outcomes. 【Methods】 From January 2010 to January 2014

the patients with unilateral ovarian cyst were enrolled in this retrospective study (EM group: 162 with ovarian endometrioma; NEM group: 152 with pathological confirmed non-endometriosis). They all received laparoscopic excision of ovarian cyst in Guangzhou People's Hospital. Six cases of EM group and 8 cases of NEM group were lost during follow-up. These two groups were divided into subgroups according to their way of pregnancy: natural pregnancy group (EM1: 92 cases; NEM1: 112 cases) and ART group (EM2: 64 cases; NEM2: 32 cases). Analysis was performed about the pregnancy outcomes between these groups. 【Results】The miscarriage rate and preterm birth rate of EM1 group were significant higher than that of ENM1 group (P=0.01; P=0.04

respectively). But there was no difference of the rate of small for gestational age between these two groups. The risk of premature rupture of membrane

placenta previa and postpartum hemorrhage was increased in EM1 group

compared to the NEM1 group (P=0.01; P=0.03; P=0.02

respectively). The risk of premature rupture of membrane of EM2 group was also significantly higher than NEM2 group (P=0.03). 【Conclusions】 Ovarian endometrioma increased the risk of miscarriage rate

preterm birth

premature rupture of membrane and placenta previa during pregnancy and also increased the risk of postpartum hemmorrhage.