OÖOsman Onur Özkavak

Osman Onur Özkavak

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Osman Onur Özkavak has a total of 56 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Perinatal Outcomes of Fetal Intra‐Abdominal Umbilical Vein Varix: A Retrospective Cohort Study

    by Esra Karatas, Osman Onur Ozkavak, Ayse Altındis Bal, Burcu Bozkurt Ozdal, Fatma Doga Ocal, Atakan Tanacan, Ozgür Kara, Dilek Sahin

    Purpose: To investigate the ultrasonographic characteristics and perinatal outcomes of fetuses diagnosed with FIUVV and compare isolated FIUVV cases with low‐risk pregnancies. Methods: This retrospective study was conducted among patients diagnosed with FIUVV at a tertiary referral center between 2020 and 2024, along with a control group of low‐risk pregnancies. The gestational age at the diagnosis and birth, the presence of additional structural and/or chromosomal anomalies in the fetus, and neonatal outcomes were recorded. Results: A total of 66 fetuses were included in the study, comprising 26 diagnosed with FIUVV and 40 in the control group. Additional structural abnormalities were identified in 23.1% of FIUVV cases, and chromosomal abnormalities were detected in three nonisolated cases. In the comparison of isolated FIUVV cases with the control group, fetal growth restriction (FGR) and preterm birth were significantly higher in FIUVV cases. Conclusion: FIUVV, even when identified as an isolated finding, may be associated with an increased risk of adverse perinatal outcomes. Careful prenatal surveillance for fetal growth, along with screening for additional structural abnormalities, may contribute to more effective clinical management of these cases.

  • Response: Prenatal and postnatal characteristics of fetal abdominal cysts and the role of prenatal ultrasonography

    by Esra Karatas, Osman Onur Ozkavak, Gülcan Okutucu, Burcu Bozkurt Ozdal, Atakan Tanacan, Fatma Doga Ocal, Ozgur Kara, Dilek Sahin

  • Prenatal and postnatal characteristics of fetal abdominal cysts and the role of prenatal ultrasonography

    by Esra Karatas, Osman Onur Ozkavak, Gülcan Okutucu, Burcu Bozkurt Ozdal, Atakan Tanacan, Fatma Doga Ocal, Ozgur Kara, Dilek Sahin

    Objective: This study investigates the prenatal characteristics and postnatal outcomes of fetal abdominal cysts and evaluates the diagnostic performance of prenatal ultrasonography (US). Methods: All cases of fetal abdominal cystic lesions followed up in our center between 2020 and 2024 were retrospectively analyzed. Cysts of urinary system origin and major complex multiple organ anomaly cases were excluded. Cysts were divided into subgroups according to prenatal diagnosis. Sensitivity, specificity, positive predictive value, false positive rate, and accuracy of prenatal US were calculated for each subgroup. Results: A total of 86 cases were included in the study. The majority of cases diagnosed by prenatal ultrasonography were of ovarian origin (39.5%), followed by duplication cysts (16.2%) and choledochal cysts (11.6%). Five cases resulted in termination of pregnancy, and two cases resulted in intrauterine fetal death. After delivery, 25.3% of cases required surgical intervention. When comparing prenatal and postnatal diagnoses, the overall sensitivity, specificity, and accuracy of prenatal ultrasonography were 98.61%, 98.44%, and 98.44%, respectively. Conclusion: Prenatal diagnosis of fetal abdominal cysts is important for appropriate management and counseling. The etiology of cysts can be accurately diagnosed by prenatal ultrasonography in approximately 85% of cases.


  • Erken İkinci Trimester Karaciğer Spesifik Biyobelirteçlerin Gebeliğin İntrahepatik Kolestazındaki Öngörüsü

    by Esra Karatas, Atakan Tanacan, Osman Onur Özkavak, Gülnihal Reyhan Toptaş, Burcu Bozkurt Özdal, Ayşe Altındiş Bal, Özgür Kara, Dilek Sahin

    Özet Amaç: Gebelikte intrahepatik kolestaz (ICP), gebelikle ilişkili en yaygın karaciğer hastalığıdır ve olumsuz obstetrik sonuçlarla ilişkilidir. ICP'nin tahmini son zamanlarda önemli ilgi görmüştür. Bu çalışmanın amacı, ICP'nin tahmini için ikinci trimesterin başlarında yapılan tarama ve rutin kan parametrelerinin etkinliğini değerlendirmektir. Gereç ve Yöntem: Çalışmaya, ICP'li 120 hamile kadın ve kontrol grubunda 120 hamile kadın retrospektif olarak dahil edildi. Erken ikinci trimester karaciğer transaminaz enzimleri (AST: aspartat aminotransferaz, ALT: alanin aminotransferaz), alfa-fetoprotein (AFP) ve AFP-transaminaz oranı değerlendirildi. Bulgular: Tüm karaciğer spesifik biyobelirteçler (AST, ALT ve AFP) kontrol grubuna kıyasla ICP grubunda anlamlı olarak daha yüksekti. AFP-transaminaz oranı, sağlıklı hamile kadınlara kıyasla ICP grubunda anlamlı olarak daha düşüktü. ICP tahmini için optimal kesme değeri AFP için 31,650 (AUC 0,668, %69,4 duyarlılık, %62,5 özgüllük) ve AFP/transaminaz için 0,048 (AUC 0,755, %53,2 duyarlılık, %90 özgüllük) idi. Sonuç: İkinci trimesterin başlarında analiz edilen AFP düzeyleri ve AFP-transaminaz oranının analizi, gebeliğin ilerleyen dönemlerinde ICP gelişiminin tahmin edilmesinde yararlı olabilir.

  • Open Access

    Postpartum Kanama: Tanım,Önleme ve Yönetim – Klinik Rehber

    by Gülcan Okutucu, Ece Atalay, Nazlı Orhan, Gülnihal Reyhan Toptaş, Uğurcan Zorlu, Esra Karataş, Hasan Altınsoy, Ezgi Başaran, Osman Onur Özkavak, Betül Akgün Aktaş, et al.

  • Open Access

    Postpartum Dönemde Hasta Yönetimi

    by Osman Onur Özkavak

    Postpartum dönem, gebelikten anneliğe geçiş dönemidir. Gebelik dönemindeki fizyolojik değişikliklerin hızla geriye döndüğü bu dönem, kendine özgü problemlerle birliktedir ve bu problemlerin zamanında tanınıp uygun şekilde yönetilmesine ihtiyaç vardır. Doğumun sonucu, doğum şekli, gebelikteki komplikasyonlar, maternal özellikler, sağlık hizmetlerinin yeterliliği ve hatta aile içi dinamikler gibi pek çok faktörden etkilenen bu dönemde en sık karşılaşılan sorunlar; anemi, artmış venöz tromboemboli riski ve psikolojik sorunlardır. Mevcut bölümde bu sorunların tarama, tanı, önleme ve tedavi stratejileri ile ilgili güncel literatürden elde edilen bilgilere yer verilmiştir.

  • Could the First Trimester Complete Blood Cell Indices Be Used to Predict Adverse Outcomes in Pregnant Women with Asthma?

    by Hakkı Şerbetçi, Atakan Tanacan, Refaettin Şahin, Osman Onur Özkavak, Zahid Ağaoğlu, Şengül Kara, Özgür Kara, Dilek Sahin

    The objective of this study was to investigate the efficacy of complete blood cell indices, specifically the neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and systemic immune-response index (SIRI), in predicting composite adverse outcomes in pregnant women with asthma. This study employed a retrospective cohort design, enrolling 307 low-risk pregnant women and 97 pregnant women with asthma. The neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and systemic immune-response index (SIRI) were compared between pregnant women with asthma and the low-risk pregnancy group in the first trimester. A significant difference was observed in the first trimester SII between pregnant women with asthma and the low-risk pregnancy group (p=0.034). The neutrophil-to-lymphocyte ratio (NLR) and systemic immune response index (SIRI) demonstrated no significant differences between the groups. Moreover, pregnant women with asthma had significantly higher eosinophil count values as expected. The first trimester white blood cell count (WBC) and platelet count (PLT) were found to be significantly higher in the asthma group (p=0.014 and p=0.031, respectively). In the asthma group, no significant difference was found between the composite adverse pregnancy outcomes due to SII, SIRI, and NLR. Pregnant women with asthma exhibited significantly elevated values for SII, WBC, PLT and eosinophils. In our study, we observed no association between groups in complete blood cell indices due to the composite adverse effects of pregnancy. Further studies with larger groups are required to evaluate the efficacy of complete blood cell indices in pregnant women with asthma.

  • Unraveling preeclampsia: Is the fibrinogen‐to‐albumin ratio the key to early risk assessment?

    by Uğurcan Zorlu, Osman Onur Özkavak, Hakkı Şerbetçi, Esra Karataş, Gülcan Okutucu, Atakan Tanaçan, Özgür Kara, Dilek Şahin

    Objective: Preeclampsia is a significant cause of maternal and neonatal morbidity and mortality. Early prediction is crucial for improving perinatal outcomes and enabling timely prophylactic interventions. This study aims to evaluate the predictive value of the fibrinogen‐to‐albumin ratio (FAR) in the first trimester for preeclampsia, its severity, and associated adverse pregnancy outcomes. Methods: This retrospective cohort study was conducted at the Perinatology Clinic of Bilkent City Hospital between January 2022 and April 2022. The records of 2116 pregnant women who underwent first‐trimester combined screening at 12 weeks of gestation were reviewed, and after applying exclusion criteria, 112 women diagnosed with preeclampsia were identified. An equal number of normotensive pregnant women were randomly selected as controls from the same hospital database within the same period. Maternal blood samples were analyzed for fibrinogen and albumin levels, and the FAR was calculated. Clinical and neonatal outcomes were recorded. Statistical analyses included independent t ‐tests, χ 2 ‐tests, receiver operating characteristic (ROC) curve analysis, and logistic regression modeling to evaluate the predictive value of FAR for preeclampsia. Results: Fibrinogen levels were significantly higher in the preeclampsia group (4.64 ± 1.21 g/L) compared to controls (3.94 ± 0.97 g/L, P = 0.032). The FAR was also significantly elevated in the preeclampsia group (0.128 ± 0.04) versus controls (0.106 ± 0.03, P = 0.012). ROC analysis demonstrated good predictive performance for FAR in identifying preeclampsia (area under the curve [AUC]: 0.79; sensitivity: 86.1%, specificity: 70.6%) and severe preeclampsia (AUC: 0.83; sensitivity: 88.6%, specificity: 74.5%). Higher FAR was significantly associated with an increased risk of placental abruption (odds ratio [OR]: 2.1, P = 0.018), neonatal respiratory distress syndrome (OR: 2.25, P = 0.017), and neonatal intensive care unit admission (OR: 2.19, P = 0.018). Conclusion: The FAR is a promising biomarker for the early prediction of preeclampsia, its severity, and adverse perinatal outcomes. Given its accessibility, affordability, and strong predictive value, FAR could be integrated into first‐trimester screening protocols alongside existing markers to improve early risk stratification. Further multi‐center validation studies are recommended to optimize predictive models for clinical use.


  • Predictive Value of First‐Trimester Aggregate Index of Systemic Inflammation (AISI) and Other Inflammatory Indices for Gestational Diabetes Mellitus and Associated Obstetric Outcomes

    by Esra Karatas, Atakan Tanacan, Osman Onur Ozkavak, Burcu Bozkurt Ozdal, Hatice Betul Ucar, Ozgur Kara, Dilek Sahin

    Problem: To investigate the value of the first‐trimester aggregate index of systemic inflammation (AISI) and other combined inflammatory markers in the prediction of gestational diabetes mellitus (GDM) and related obstetric outcomes.Method of Study: The data of pregnant women diagnosed with GDM between September 2021 and November 2024, as well as an equal number of control patients, were retrospectively analyzed. The patients' AISI, neutrophil lymphocyte ratio (NLR), systemic immune‐inflammatory index (SII), and systemic inflammatory response index (SIRI) values were calculated from the hemogram parameters of the participants at 11–14 weeks of gestation. The clinical characteristics, laboratory results, combined inflammatory indices, obstetric outcomes, the need for neonatal intensive care unit (NICU) admission, and the presence of composite adverse perinatal outcome (CAPO) of the groups were then compared. Receiver operating characteristic (ROC) curve analyses were performed to investigate the value of the indices that reached statistical significance in predicting GDM.Results: The GDM group exhibited significantly higher SII and AISI values, rate of NICU admission, and CAPO compared to the control group (p = 0.036, p = 0.011, p < 0.01, and p < 0.01, respectively). The gestational age at birth was significantly lower in the GDM group compared to the control group, while the neonatal weight was higher (p < 0.01, p < 0.01, respectively). The ROC curve analyses yielded an area under the curve (AUC) of 0.566 and 0.581 for SII and AISI for GDM prediction, respectively (p = 0.036 and p = 0.011, respectively).Conclusions: First‐trimester AISI and SII may be useful markers for identifying pregnancies at high risk for developing GDM.


  • Open Access

    The Utility of Albumin-Bilirubin Score as a Prognostic Marker in Preeclampsia

    by Osman Onur Özkavak, Dilek Sahin

    Aims: To evaluate the utility of the albumin bilirubin (ALBI) score as a liver function test and prognostic marker in patients with preeclampsia. Materials and Methods: A total of 374 patients were enrolled in the study (148 preeclampsia without severe features, 112 preeclampsia with severe features, 114 controls). The study compared clinical and demographic features, laboratory findings and ALBI scores between the three groups. Also, receiver operating curve (ROC) analysis was used for the estimation of the predictive value of the ALBI score for the severity of preeclampsia and maternal/neonatal poor prognosis. Results: The median ALBI score of the severe preeclampsia group was significantly higher than mild preeclampsia and control groups (p