Research Project: Sonografik Kısa Serviksi Bulunan Hastalarda Vajinal, Plasental ve Neonatal Mikrobiyota ve Mikobiyata Erken Doğum ile İlişkisinin Değ erlendirilmesi
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Contributors
Funders
ID
TB.00471
Authors
Çelik, Ebru
Faculty Member
Publications
The vaginal microbiome composition during pregnancy in a region compromising different ethnic origins
(Springer, 2024) Can, Füsun; Çekiç, Sebile Güler; Çelik, Ebru; Gürsoy, Attila; Gürsoy, Tuğba; Keskin, Özlem; Kuyucu, Gülin Özcan; Özek, Murat Aykut; Paerhati, Erxiati; Turğal, Mert; Ünal, Ceren; Vatansever, Cansel; School of Medicine; Department of Computer Engineering; Department of Chemical and Biological Engineering; KUISCID (Koç University İşbank Center for Infectious Diseases); Yes; College of Engineering; Research Center; SCHOOL OF MEDICINE
Background:The vaginal microbiota plays a significant role in pregnancy outcomes and newborn health. Indeed, the composition and diversity of the vaginal microbiota can vary among different ethnic groups. Our study aimed to investigate the composition of the vaginal microbiome throughout the three trimesters of pregnancy and to identify any potential variations or patterns in the Turkish population compromising mixed ethnicities.MethodWe conducted a longitudinal study to characterize the vaginal microbiota of pregnant women. The study included a total of 25 participants, and the samples were collected at each trimester: 11-13 weeks, 20-24 weeks and 28-34 weeks gestation.ResultsLactobacillus species were consistently found to be dominant in the vaginal microbiota throughout all trimesters of pregnancy. Among Lactobacillus species, L. crispatus had the highest abundance in all trimesters (40.6%, 40.8% and 44.4%, respectively). L. iners was the second most prevalent species (28.5%, 31% and 25.04, respectively). Our findings reveal that the dominant composition of the vaginal microbiota aligns with the CST-type I, commonly observed in the European population.ConclusionsThis suggests that there are shared mechanisms influencing the microbial communities in the vagina, which are likely influenced by factors such as genetics, lifestyle, and cultural behaviors rather than ethnicity alone. The complex interplay of these factors contributes to the establishment and maintenance of the vaginal microbiota during pregnancy. Understanding the underlying mechanisms and their impact on vaginal health across diverse populations is essential for improving pregnancy outcomes.The study was approved by the Koc University Ethical Committee (no:2019.093.IRB2.030) and registered at the clinical trials.ConclusionsThis suggests that there are shared mechanisms influencing the microbial communities in the vagina, which are likely influenced by factors such as genetics, lifestyle, and cultural behaviors rather than ethnicity alone. The complex interplay of these factors contributes to the establishment and maintenance of the vaginal microbiota during pregnancy. Understanding the underlying mechanisms and their impact on vaginal health across diverse populations is essential for improving pregnancy outcomes.The study was approved by the Koc University Ethical Committee (no:2019.093.IRB2.030) and registered at the clinical trials.
Alterations in vaginal microbiome in women with short cervix: longitudinal study of microbial diversity and impact of vaginal progesterone treatment
(Wiley, 2025) Çelik, Ebru; Özcan, Gülin; Vatansever, Cansel; Paerhati, Erxiati; Ünal, Ceren; Çekiç, Sebile Güler; Gürsoy, Attila; Keskin, Özlem; Tuğral, Mert; Can, Füsun; Gürsoy, Tuğba; Özten, Muhammet Atay; Uygur, L.; KUISCID (Koç University İşbank Center for Infectious Diseases); School of Medicine; Yes; SCHOOL OF MEDICINE; Research Center; College of Engineering
Objectives A short cervix is a known risk factor for preterm birth, and imbalances in the vaginal microbiome, such as low relative abundance of Lactobacillus, may be associated with an increased risk of preterm birth. The aim of this study was to evaluate differences in the vaginal microbiome between women with a short cervix and those with normal cervical length in the second trimester. Additionally, we aimed to assess longitudinal changes in microbial diversity during pregnancy, as well as the impact of vaginal progesterone treatment on vaginal microenvironment in women with a short cervix. Methods This was a prospective, longitudinal study conducted at Koc University Hospital between January 2020 and May 2023, in women with a singleton pregnancy with a short cervical length (<= 25 mm) in the second trimester (20 + 0 to 24 + 6 weeks' gestation). After diagnosis of short cervix, administration of 200 mg vaginal progesterone daily was initiated. The control group comprised women with a normal cervical length (> 25 mm) in the second trimester, matched for age and body mass index (BMI). Cervicovaginal swabs were collected from the posterior fornix at three gestational-age ranges: in the first trimester (11 + 0 to 13 + 6 weeks), the second trimester (20 + 0 to 24 + 6 weeks) and the third trimester (28 + 0 to 34 + 6 weeks), and cervical length was measured following sample collection. DNA was extracted and the 16S rRNA bacterial gene was sequenced to analyze and compare the vaginal microbiome between women with a short cervix and controls. We also assessed the microbiome longitudinally in each group, across the first, second and third trimesters. In the short-cervix group, we also compared the microbiome before initiation of progesterone treatment in the second trimester and 4 weeks after its initiation. Results Among 490 pregnant women who underwent first-trimester screening during the study period and had vaginal swabs collected, short cervical length was detected in 31 at the second-trimester scan. These women formed the study group. A further 27 women, with a normal cervical length, were matched for BMI and age and assigned to the control group. During the second trimester, women with a short cervix exhibited greater species diversity compared with the control group; this was suggested by the higher Shannon index (0.45 vs 0.33; P = 0.135), which reflects species richness and evenness, and further demonstrated by the higher Chao index (20.2 vs 13.8; P = 0.018), which estimates species richness. In the second trimester, Lactobacillus was less abundant in women with a short cervix than in the control group, although the difference did not reach significance (86.8% vs 95.5%; P = 0.091). At the phylum level, in women with a short cervix compared to those with normal cervical length, the relative abundance of Firmicutes, to which the genus Lactobacillus belongs, was significantly lower (90.7% vs 97.6%; P = 0.041), while the relative abundances of both Bacteroidota (1.73% vs 0.4%; P = 0.004) and Proteobacteria (0.2% vs 0.01%; P = 0.007) were higher. In the second trimester, the relative abundance of Lactobacillus gasseri was significantly lower in women with a short cervix compared to controls (4.7% vs 13.8%; P = 0.023). In the longitudinal analysis of the vaginal microbiome, there were no significant differences among the trimesters in the control group. In contrast, in those with a short cervix, there was a notable decrease in the amount of Lactobacillus crispatus, from 55.0% in the first trimester to 36. 1% in the second trimester (P = 0.052). In women with a short cervix, there was no significant difference in bacterial diversity after vs before progesterone treatment (Chao index, 22.6 vs 20.5; P = 0.609). Conclusion These findings highlight the significant alterations in the vaginal microbiome of pregnant women with a short cervix in comparison to those with normal cervical length, particularly in terms of higher species diversity and distinct community composition. The study also shows that vaginal progesterone treatment in women with a short cervix does not alter the vaginal microbiome, suggesting that it is a safe and effective intervention without disrupting the vaginal microbial balance. Understanding the relationship between cervical length and the vaginal microbiome is essential for developing strategies to reduce the risk of preterm birth in high-risk populations. (c) 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
