The Effect of Ovarian Endometriosis on Pregnancy Outcomes in Spontaneous Pregnancies

<b>Background:</b> This study investigates the impact of ovarian endometriosis on pregnancy outcomes. <b>Methods:</b> A retrospective analysis was conducted at Etlik Zübeyde Hanım Women's Diseases Training and Research Hospital between January 2019 and December 2024, including 1127 pregnant women-170 with ovarian endometriosis and 957 healthy controls. Pregnancies achieved via assisted reproductive techniques were excluded. Statistical analyses were performed using appropriate tests, and a <i>p</i>-value < 0.05 was considered significant. <b>Results:</b> Women with ovarian endometriosis had higher rates of miscarriage (21.8% vs. 7.5%), preterm birth (15.0% vs. 8.8%), and placenta previa (4.7% vs. 0.6%), with adjusted odds ratios (OR) of 3.41, 1.84, and 7.82, respectively. No significant differences were observed in terms of gestational diabetes, hypertensive disorders, fetal growth restriction (FGR), intrahepatic cholestasis of pregnancy (ICP), placental abruption, or preterm premature rupture of membranes (PPROM). Cyst size and bilaterality were not associated with complications. <b>Conclusions:</b> Spontaneously conceiving women with ovarian endometriosis are at increased risk for miscarriage, placenta previa, and preterm birth. Prospective randomized studies are warranted to validate these findings.