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Long N, Fu Y, Wang Z, Feng L, Ji T. Differential predictive utility of preoperative cervical length for preterm birth among various indications for cervical cerclage: a retrospective cohort study. J Matern Fetal Neonatal Med 2025; 38:2479751. [PMID: 40113267 DOI: 10.1080/14767058.2025.2479751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2024] [Revised: 03/02/2025] [Accepted: 03/09/2025] [Indexed: 03/22/2025]
Abstract
OBJECTIVES To investigate the predictive utility of preoperative cervical length (CL) for preterm birth (PTB) in cervical cerclage with different surgical indications. METHODS This study included data from 289 pregnant women who underwent transvaginal cervical cerclage at the Wuhan Tongji Hospital (Hubei, China) between 2015 and 2024. Participants were divided into three groups according to surgical indication(s) for cerclage: history indicated (n = 173); ultrasound indicated (n = 89); and examination indicated (n = 27). RESULTS The area under the receiver operating characteristic curve (AUC) revealed that preoperative CL for PTB was greater for ultrasound-indicated cerclage (AUC 0.6613, cutoff 13.5 mm) than that for history-indicated cerclage (AUC 0.5675, optimal cutoff 30.5 mm). In history-indicated cerclage, there were no difference in the rate of PTBs between preoperative CL > 30.5 mm and ≤ 30.5 mm, nor in the rate of postoperative CL ≤ 15 mm during the fourth week. In the ultrasound-indicated group, compared with preoperative CL > 13.5 mm, women with a CL ≤ 13.5 mm exhibited a higher rate of PTB (82.1% versus 48.0%; p < .001), and a higher rate of postoperative CL ≤ 15 mm in the fourth week (71.4% versus 37.5%; p = 0.009). CONCLUSION The correlation between preoperative CL and PTB varied depending on the indication(s) for cerclage, and changes in postoperative CL contributed to varying predictive utility.
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Affiliation(s)
- Nary Long
- National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yilin Fu
- National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zizhuo Wang
- National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ling Feng
- National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Teng Ji
- National Clinical Research Center for Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Ługowski F, Babińska J, Jasak K, Pastwa K, Litwińska-Korcz E, Litwińska M, Jabiry-Zieniewicz Z, Szpotańska-Sikorska M. Comparison of Perinatal Outcomes Following Elective and Emergency Cerclage Insertion: A Ten-Year Retrospective Cohort Study. J Clin Med 2025; 14:3515. [PMID: 40429510 PMCID: PMC12112186 DOI: 10.3390/jcm14103515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2025] [Revised: 05/14/2025] [Accepted: 05/15/2025] [Indexed: 05/29/2025] Open
Abstract
Background: Cervical insufficiency (CI) is a painless cervix dilation in the second or early third trimester due to a structural or functional defect. However, CI is often diagnosed retrospectively. A cervix with CI cannot retain the fetus. This condition significantly increases the morbidity associated with extreme prematurity. Women diagnosed with cervical incompetence and dilatation in the mid-second trimester are offered interventions to prolong the duration of pregnancy, with the mainstay of therapy being emergency cerclage. A prophylactic cerclage may be offered to women with a history of extremely preterm birth due to isthmic cervical incompetence. Aim: The aim of this study was to evaluate the perinatal outcomes of elective and emergency cerclages. Materials and Methods: A 10-year retrospective analysis, from 1 January 2015 to 29 February 2024 of pregnancies with indications for cervical cerclage, was conducted. Obstetric and neonatal outcomes were assessed. Results: Prophylactic cervical cerclage was performed in 43 (57%) and emergency cerclage in 32 (43%) of all analyzed cases. The mean prolongation of gestation (measured as the period between cerclage insertion and delivery) was higher in the elective cerclage group compared with the emergency cerclage group (18.6 ± 5.4 vs. 12.2 ± 6.4 weeks; p < 0.0001). The mean gestational week at cerclage removal was also higher in the elective group (36.1 ± 2.2 vs. 31.4 ± 5.6 weeks; p < 0.001). Deliveries in the extreme prematurity period (before 28 completed weeks of gestation) were five times more often in the rescue cerclage group. A significantly higher mean birthweight was reported in the elective cerclage group, at 2920.4 ± 946.8 g vs. 2078.8 ± 1147.8 g (p = 0.0004). Emergency cerclage insertion was associated with a higher need for NICU hospitalization (28% vs. 5%, p = 0.003), continuous positive airway pressure (38% vs. 2%, p < 0.0001), and intubation (22% vs. 0%, p = 0.003). Conclusions: While elective cerclage is associated with more favorable perinatal and neonatal outcomes, this likely reflects earlier intervention in lower-risk pregnancies rather than inherent superiority of the approach. Emergency cerclage, performed under urgent and often suboptimal conditions, remains a critical and effective intervention capable of prolonging gestation and improving neonatal survival in high-risk cases.
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Yalınkaya A, Oğlak SC, Gündüz R, Yılmaz EZ, Bolluk G, Yayla M. Outcomes of emergency cervical cerclage after amnioreduction in twin pregnancies with a fully dilated cervix and amniotic membrane prolapse. J Turk Ger Gynecol Assoc 2025; 26:26-33. [PMID: 40077964 PMCID: PMC11905194 DOI: 10.4274/jtgga.galenos.2024.2024-9-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2025] Open
Abstract
Objective The aim of this study was to evaluate the effectiveness of emergency cervical cerclage (EmC) in twin pregnancies with a fully dilated cervix and amniotic membrane prolapse. Material and Methods This retrospective study examined records from December 2015 to December 2022 and included 20 twin pregnancies. The patients were divided into two groups, the EmC group (EmC group) and the no EmC (control) group, and pregnancy outcomes were compared. Results EmC was performed after amnioreduction in 11 twin pregnancies. Nine patients who refused EmC were followed up with expectant management. The mean gestational age at first examination was similar between the EmC (21.36±1.62 weeks) and control group (21.00±3.16 weeks, p=0.372). The median (range) volume of removed amniotic fluid was 151.82 (120-420) mL. Cases in the EmC group gained a significantly longer delay until delivery (47.72±28.14 days) compared to controls (2.33±0.5 days, p<0.001). All of the women in the control group gave birth within three days following admission to hospital. The mean gestational age at birth was significantly higher in the EmC group (28.18±4.53 weeks) than in the control group (21.57±3.53 weeks, p<0.001). Thirteen (59.09%) infants survived in the EmC group while only two infants (22.22%) of one patient survived in the control group (p<0.001). Conclusion EmC increases the survival rate of infants by prolonging the gestational age at delivery in twin pregnancies. Clinicians and patients should be encouraged regarding the use of EmC in twin pregnancies with a fully dilated cervix and prolapsed amniotic membranes.
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Affiliation(s)
- Ahmet Yalınkaya
- Department of Obstetrics and Gynecology, Dicle University Faculty of Medicine, Diyarbakır, Türkiye
| | - Süleyman Cemil Oğlak
- Clinic of Obstetrics and Gynecology, University of Health Sciences Türkiye, Gazi Yaşargil Training and Research Hospital, Diyarbakır, Türkiye
| | - Reyhan Gündüz
- Department of Obstetrics and Gynecology, Dicle University Faculty of Medicine, Diyarbakır, Türkiye
| | - Emine Zeynep Yılmaz
- Clinic of Obstetrics and Gynecology, Bahçelievler Memorial Hospital, İstanbul, Türkiye
| | - Gökhan Bolluk
- Clinic of Perinatology, University of Health Sciences Türkiye, Başakşehir Çam and Sakura City Hospital, İstanbul, Türkiye
| | - Murat Yayla
- Clinic of Perinatology, Acıbadem Kozyatağı Hospital, İstanbul, Türkiye
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Koullali B, van Dijk CE, Kleinrouweler CE, Limpens JC, Mol BW, Oudijk MA, Pajkrt E. The effect of an exam-indicated cerclage before 24 weeks of gestation to prevent preterm birth: A systematic review and meta-analysis. Eur J Obstet Gynecol Reprod Biol X 2025; 25:100372. [PMID: 40041371 PMCID: PMC11876763 DOI: 10.1016/j.eurox.2025.100372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 01/09/2025] [Accepted: 02/07/2025] [Indexed: 03/06/2025] Open
Abstract
The effect of an exam-indicated cerclage (EIC) remains uncertain due to limited evidence from reviews covering pregnancies beyond this timeframe. With the 24-week mark serving as an international threshold for neonatal care initiation, the aim of this systematic review was to evaluate the available literature on the effectiveness of an EIC before 24 weeks of gestation. MEDLINE, EMBASE, Web of Science, CENTRAL, clinicaltrials.gov and WHO-ICTRP were searched for randomized controlled trials, cohort and case-control studies comparing EIC with expectant management in singleton pregnancies with cervical dilation ≤ 5 cm between 14 and 24 weeks of gestation to prevent preterm birth (PTB) < 37 weeks of gestation. Secondary outcomes included obstetrical and neonatal outcomes. Quality assessment was preformed using Newcastle-Ottawa Scale. Analyses were conducted using R(studio) version 3.6.1. and outcomes stated as odds ratios (OR) with 95 % confidence intervals (CI). Prospero: #CRD42019137400. The search yielded 787 potential studies. Four studies non-randomized (retrospective) could be included. Quality assessment showed overall good quality. The main weaknesses were retrospective designs, small sample sizes and the poor comparability of the intervention and control groups. The study population resulted in 215 women, among whom 163 (76 %) underwent cerclage placement and 52 (24 %) were expectantly managed. EIC compared with expectant management was associated with significant lower rates of PTB before 37 weeks (71.2 % vs 94.2 %; OR 0.11; 95 % CI 0.03-0.35), 34 weeks (49.1 % vs 86.5 %; OR 0.10; 95 % CI 0.03-0.31), 32 weeks (43.0 % vs 80.0 %; OR 0.13; 95 % CI 0.04-0.43), 28 weeks (43.0 % vs 75.0 %; OR 0.19; 95 % CI 0.07-0.51) and 24 weeks (23.3 % vs 50 %; OR 0.29; 95 % CI 0.13-0.65) of gestation, significant prolongation of the pregnancy (mean difference 39.14 days; 95 %CI 30.58-47.71; p-value <0.0001) and a greater gestational age at delivery (mean difference 4.91 weeks; 95 % CI 2.32-7.49; p-value 0.0002) compared to expectant management. The current literature suggests that EIC before 24 weeks of gestation is associated with improved pregnancy outcomes compared to expectant management. The results are limited by the lack of randomised trials and studied neonatal outcomes plus the potential for bias in the included studies.
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Affiliation(s)
- Bouchra Koullali
- Amsterdam UMC, University of Amsterdam, Department of Obstetrics and Gynaecology, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands
- Amsterdam Reproduction and Development Research Institute, Meibergdreef 9, Amsterdam 11005 AZ, the Netherlands
| | - Charlotte E. van Dijk
- Amsterdam UMC, University of Amsterdam, Department of Obstetrics and Gynaecology, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands
- Amsterdam Reproduction and Development Research Institute, Meibergdreef 9, Amsterdam 11005 AZ, the Netherlands
| | - Charlotte E. Kleinrouweler
- Amsterdam UMC, University of Amsterdam, Department of Obstetrics and Gynaecology, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands
- Amsterdam Reproduction and Development Research Institute, Meibergdreef 9, Amsterdam 11005 AZ, the Netherlands
| | - Jacqueline C.E.J.M.P. Limpens
- Amsterdam UMC, University of Amsterdam, Department of Research Support – Medical Library, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands
| | - Ben W. Mol
- School of Medicine, Monash University, Department of Obstetrics and Gynaecology, 246 Clayton Road Clayton 3168, Melbourne, Victoria, Australia
| | - Martijn A. Oudijk
- Amsterdam Reproduction and Development Research Institute, Meibergdreef 9, Amsterdam 11005 AZ, the Netherlands
- Amsterdam UMC, Vrije Universiteit van Amsterdam, Department of Obstetrics and Gynaecology, De Boelelaan 1117, Amsterdam 1081 HV, the Netherlands
| | - Eva Pajkrt
- Amsterdam UMC, University of Amsterdam, Department of Obstetrics and Gynaecology, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands
- Amsterdam Reproduction and Development Research Institute, Meibergdreef 9, Amsterdam 11005 AZ, the Netherlands
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Park KH, Lee KN, Choi BY, Lee MJ, Jeong DE. Rescue Cerclage in Women With Acute Cervical Insufficiency and Intra-Amniotic Inflammation: A Retrospective Cohort Study. J Korean Med Sci 2024; 39:e310. [PMID: 39497566 PMCID: PMC11538575 DOI: 10.3346/jkms.2024.39.e310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 09/12/2024] [Indexed: 11/08/2024] Open
Abstract
BACKGROUND To assess the effectiveness of rescue cerclage concerning pregnancy and neonatal outcomes in women with acute cervical insufficiency (CI) complicated with intra-amniotic inflammation (IAI) compared with those managed expectantly. METHODS This retrospective cohort study included 87 consecutive singleton pregnant women (17-25 weeks) with acute CI who underwent amniocentesis to assess IAI. Amniotic fluid (AF) samples were assayed for interleukin-6 to define IAI (≥ 2.6 ng/mL). Primary and secondary outcomes were assessed in a subset of CI patients with IAI. The primary outcome measures were spontaneous preterm birth (SPTB) at < 28 and < 34 weeks, and the secondary outcomes were interval from sampling to delivery, neonatal survival, neonatal birth weight, and histologic and clinical chorioamnionitis. Macrolide antibiotics were prescribed depending on the type of microorganism isolated from the AF, clinically suspected IAI, and the discretion of the attending clinician. RESULTS IAI was identified in 65.5% (57/87) of patients with CI, of whom 73.6% (42/57) were treated with macrolide antibiotics. Among the CI patients with IAI (n = 57), 40 underwent rescue cerclage and 17 were expectantly managed. The rates of SPTBs at < 28 and < 34 weeks were significantly lower and the latency period was significantly longer in the cerclage group than in the group that was managed expectantly. The median birth weight and neonatal survival rate were significantly higher in the cerclage group than in the group that was managed expectantly. However, the rates of histologic and clinical chorioamnionitis did not differ between the groups. Multivariable analyses revealed that rescue cerclage placement and administration of macrolide antibiotics were significantly associated with a decrease in SPTBs at < 28 and < 34 weeks, prolonged gestational latency, and increased likelihood of neonatal survival, after adjusting for possible confounding parameters; however, macrolide antibiotic administration did not reach statistical significance with respect to SPTB at < 34 weeks and neonatal survival (P = 0.076 and 0.063, respectively). CONCLUSION Rescue cerclage along with macrolide antibiotic treatment may positively impact pregnancy and neonatal outcomes in women with CI complicated by IAI, compared with expectant management. These findings suggest the benefit of cerclage placement even in patients with CI complicated by IAI.
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Affiliation(s)
- Kyo Hoon Park
- Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
| | - Kyong-No Lee
- Department of Obstetrics and Gynecology, Chungnam National University Hospital, Daejeon, Korea
| | - Bo Young Choi
- Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Min Jung Lee
- Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Da Eun Jeong
- Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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Ughade PA, Shrivastava D, Chaudhari K. Rescue Cervical Cerclage for Previable Birth Prevention: A Comprehensive Review of Indications, Techniques, and Outcomes. Cureus 2024; 16:e68619. [PMID: 39371694 PMCID: PMC11450839 DOI: 10.7759/cureus.68619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2024] [Accepted: 09/04/2024] [Indexed: 10/08/2024] Open
Abstract
Cervical cerclage is a surgical intervention aimed at preventing previable birth by providing mechanical support to the cervix through the placement of a suture. This procedure is primarily indicated for cases of cervical incompetence, where the cervix is prone to premature dilation and can lead to early miscarriage or preterm birth. This review seeks to comprehensively analyze rescue cervical cerclage (RCC), focusing on its indications, techniques, and outcomes. The goal is to offer an in-depth understanding of its effectiveness in preventing previable birth and to guide clinical decision-making in managing pregnancies at risk of premature delivery. A thorough literature review examined recent studies and clinical data on RCC. Key aspects evaluated include the criteria for intervention, various surgical techniques employed, and the associated maternal and fetal outcomes. Comparative analysis was also performed with other preventive measures, such as progesterone therapy and bed rest. RCC has demonstrated efficacy in reducing the incidence of previable births, particularly when performed in cases of identified cervical incompetence or shortening. The review highlights variations in the technique, such as McDonald and Shirodkar cerclage, and discusses their relative success rates and potential complications. The procedure is associated with improved pregnancy outcomes and reduced risk of previable birth, though it carries some risks, including infection and cervical laceration. RCC remains a valuable intervention for preventing previable births in selected patients. This review underscores its importance in managing pregnancies at risk due to cervical incompetence and provides a detailed evaluation of its indications, techniques, and outcomes. Future research should optimize criteria for cerclage placement and explore novel strategies to enhance its effectiveness and safety.
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Affiliation(s)
- Prachi A Ughade
- Obstetrics and Gynaecology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Deepti Shrivastava
- Obstetrics and Gynaecology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Kamlesh Chaudhari
- Obstetrics and Gynaecology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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Yi X, Zhang D, Yang J, Gao H, Cai H, Cong J, Lin C. Analysis of perinatal outcomes for emergency cervical cerclage in singleton pregnancies at 24-28 weeks of gestation. Arch Gynecol Obstet 2024; 310:229-235. [PMID: 38649500 PMCID: PMC11168987 DOI: 10.1007/s00404-024-07493-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 03/24/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Cervical cerclage is the only effective treatment for cervical insufficiency, effectively preventing late miscarriage and preterm birth. The effectiveness and safety of emergency cervical cerclage (ECC) as an emergency treatment when the cervix is already dilated or when there is protrusion of the fetal membranes into the vagina remain controversial, especially in pregnancies at 24-28 weeks when the fetus is viable. There is still no consensus on whether emergency cervical cerclage should be performed in such cases. PURPOSE To investigate the effectiveness and safety of emergency cervical cerclage in singleton pregnant women at 24-28 weeks of gestation. METHODS This study employed a single-center prospective cohort design, enrolling singleton pregnant women at 24-28 weeks of gestation with ultrasound or physical examination indicating cervical dilation or even membrane protrusion. Emergency cervical cerclage was compared with conservative treatment. The primary endpoints included a comprehensive assessment of perinatal pregnancy loss, significant neonatal morbidity, and adverse neonatal outcomes. Secondary endpoints included prolonged gestational age, preterm birth, neonatal hospitalization rate, premature rupture of membranes, and intrauterine infection/chorioamnionitis. RESULTS From June 2021 to March 2023, a total of 133 pregnant women participated in this study, with 125 completing the trial, and were allocated to either the Emergency Cervical Cerclage (ECC) group (72 cases) or the conservative treatment group (53 cases) based on informed consent from the pregnant women. The rate of adverse neonatal outcomes was 8.33% in the ECC group and 26.42% in the conservative treatment (CT) group, with a statistically significant difference (P = 0.06). There were no significant differences between the two groups in terms of perinatal pregnancy loss and significant neonatal morbidity. The conservative treatment group had a mean prolonged gestational age of 63.0 (23.0, 79.5) days, while the ECC group had 84.0 (72.5, 89.0) days, with a statistically significant difference between the two groups (P < 0.001). Compared with CT group, the ECC group showed a significantly reduced incidence of preterm birth before 28 weeks, 32 weeks, and 34 weeks, with statistical significance (P = 0.046, 0.007, 0.001), as well as a significantly decreased neonatal hospitalization rate (P = 0.013, 0.031). Additionally, ECC treatment did not increase the risk of preterm premature rupture of membranes or intrauterine infection/chorioamnionitis, with no statistically significant differences (P = 0.406, 0.397). CONCLUSION In singleton pregnant women with cervical insufficiency at 24-28 weeks of gestation, emergency cervical cerclage can reduce adverse neonatal pregnancy outcomes, effectively prolong gestational age, decrease preterm births before 28 weeks, 32 weeks, and 34 weeks, lower neonatal hospitalization rates, and does not increase the risk of preterm premature rupture of membranes or intrauterine infection/chorioamnionitis.
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Affiliation(s)
- Xiling Yi
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China
| | - Dan Zhang
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China
| | - Jing Yang
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China.
| | - Hongyan Gao
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China
| | - Hengyu Cai
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China
| | - Jianping Cong
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China
| | - Chengli Lin
- Department of Obstetrics and Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, 110000, Liaoning, China
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