en 36452188 <p>Background: Placenta accreta spectrum (PAS) disorder is an important life-threatening problem. The purpose of the current study was to determine the frequency, risk factors, and pregnancy outcomes of PAS in our population.<br /> Methods: This is a case-control study using the data from a main tertiary referral university hospital in Ahvaz, southwest of Iran. The sample included 187 cases diagnosed with placenta accreta spectrum from 2015 to 2019 and 552 controls without PAS. A multivariable logistic regression model was used to find independent risk factors with 95% confidence interval. Pregnancy outcomes were evaluated using chi-square, t-test, and Mann-Whitney U test and p&lt;0.05 were considered statistically significant.<br /> Results: The frequency of PAS during the study period was 3.7/1000 deliveries (0.37%). It was found that multiparity (&ge;3 deliveries, OR=2.05: 95%CI:1.21-3.47) and multigravidity (&ge;3 deliveries, OR=2.98: 95%CI:1.55-5.72), prior cesarean delivery (OR=52.55: 95%CI:19.73-139.96), and placenta previa (OR=27.48: 95%CI:9.62-78.5) are the independent risk factors of PAS. Complications and morbidity associated with PAS included hysterectomy (60.4% <em>vs. </em>0.7%, p&lt;0.001), cystostomy (24.1% <em>vs.</em> 0.2%, p&lt;0.001), the need for blood transfusion (73.7% <em>vs.</em> 1.4%, p&lt;0.001), intensive care unit admission of mother (42.8% <em>vs.</em> 0.2%, p&lt;0.001), duration of hospitalization (7.52&plusmn;6.34 <em>vs.</em> 1.97&plusmn;1.83, p&lt;0.001), preterm birth &lt;37 weeks (61.4% <em>vs.</em> 16.8%, p&lt;0.001), and perinatal mortality (7.4% vs. 1.8%, p&lt;0.001) which manifested statistically significant values.<br /> Conclusion: The frequency of PAS is similar to other populations.&nbsp; Prior cesarean delivery, placenta previa, multigravidity, and multiparity were independent risk factors and also perinatal hysterectomy and preterm birth were the most important complications.</p> Cesarean delivery, Placenta accreta spectrum, Placenta previa, Endometrium 279 288 https://www.jri.ir/article/140165 https://www.jri.ir/documents/fullpaper/en/140165.pdf MitraTadayonReproductive Health Promotion Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran122453NahidJavadifarReproductive Health Promotion Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Irannahidjavadifar_341@yahoo. com, Javadifar–n@ajums.ac.ir122454MaryamDastoorpoorDepartment of Epidemiology, Menopause-Andropause Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran122455NahidShahbazianFertility, Infertility, and Perinatology Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran122456