Pregnancy Outcome in Singleton and Multiple Pregnancies with Second Trimester Cerclage

Abstract

Background/Objectives: Preterm birth remains a major cause of neonatal morbidity and mortality, particularly in multiple pregnancies and in cases of cervical shortening. While cervical cerclage is established in singleton pregnancies, its efficacy in multiple gestations remains uncertain. This study compares pregnancy and neonatal outcomes following second-trimester cerclage in singleton and multiple pregnancies with a short cervix. Methods: In this retrospective cohort study, 96 women underwent second-trimester cerclage at a tertiary perinatal center between 2020 and 2024. All had a cervical length ≤ 25 mm or prolapsed membranes without infection or premature rupture. Primary outcomes included term delivery rate, gestational age, mode of delivery, and neonatal outcomes; secondary outcomes comprised surgical complications and rehospitalization, defined as the need for renewed inpatient care due to threatened preterm labor or procedure-related complications. Results: In total, 79 singleton and 17 multiple pregnancies were analyzed. Term delivery occurred more often in singletons (54%) than multiples (18%, p = 0.006). Mean gestational age at birth was 258 ± 25 days in singletons versus 228 ± 28 days in multiples (p < 0.001). Birth weight was significantly lower in multiples (1985 g vs. 2943 g; p < 0.001), and neonatal infections were more frequent (53% vs. 26%; p = 0.008). Caesarean delivery was more common in multiples (82% vs. 33%; p < 0.001). Apart from increased postoperative contractions in multiples (24% vs. 5%; p = 0.031), complication rates and rehospitalization (27% vs. 29%; p = 0.8) were similar. Conclusions: Second-trimester cerclage is less effective in preventing preterm birth in multiple pregnancies compared to singleton pregnancies; however, it appears to be associated with a stabilizing clinical course and may facilitate outpatient management in selected high-risk cases. These findings support individualized counseling and shared decision-making, particularly in multifetal gestations.

1. Introduction

Preterm birth is one of the leading causes of neonatal morbidity and mortality worldwide, with an incidence of about 8% in Germany and a significant global variation ranging from 5.3% to 11.3% [1,2]. It is defined as delivery before 37 + 0 weeks of gestation [3]. Infants born preterm—especially before 28 weeks—face a mortality rate nearly 300 times higher than those born at term, with many survivors experiencing severe long-term complications such as cerebral palsy, respiratory disorders, and developmental delays [1,4]. Women with multiple pregnancies are inherently at higher risk for preterm delivery, with more than half giving birth before 37 weeks of gestation [5]. Although multiple pregnancies account for only about 2% of all pregnancies, they contribute to over 10% of all preterm births, highlighting their disproportionate impact on adverse neonatal outcomes [1].

A shortened cervix is a well-established predictor of spontaneous preterm birth. In both singleton and multiple pregnancies, a cervical length of ≤25 mm in the second trimester is significantly associated with an increased risk of early delivery [6]. For women with a shortened cervix, interventions such as cervical cerclage, pessary placement, and progesterone supplementation have been proposed to prolong pregnancy [7,8,9]. In singleton pregnancies, second-trimester cervical cerclage has demonstrated efficacy in reducing the rate of preterm births, especially in women with a history of preterm birth [9,10]. However, in multiple pregnancies, its benefit remains controversial due to limited and conflicting evidence, complicating clinical decision-making [11]. Systematic reviews and meta-analyses have shown no benefit nor negative effects of cerclage placement in twin pregnancies with a cervical length < 25 mm [12,13,14]. In contrast, two recent meta-analyses suggest that cerclage may offer potential benefits in twin pregnancies with a cervical length < 15 mm [11,15]. Considering these uncertainties, current guidelines from the German Society for Gynaecology and Obstetrics (DGGG) advocate for individualized management strategies based on patient-specific risk factors in cases of cervical shortening [3].

In multiple pregnancies, increased uterine distension, altered cervical biomechanics, and a higher inflammatory burden may limit the mechanical effectiveness of cerclage compared to singleton pregnancies. Despite the high risk of preterm birth in this population, comparative real-world data on pregnancy outcomes and post-procedural management following second-trimester cerclage remain scarce.

This study therefore aims to compare pregnancy and neonatal outcomes following second-trimester cerclage in singleton and multiple pregnancies with a short cervix. In addition, complications and the need for postoperative inpatient care, including rehospitalization, were documented to assess the post-procedural impact on maternal quality of life, an aspect that has been insufficiently addressed in previous studies.

2. Materials and Methods

This retrospective cohort study was conducted at the Department of Obstetrics and Gynaecology at the University Clinic St. Hedwig in Regensburg, Germany, between 2020 and 2024.

Eligible participants were all women treated with a therapeutic cerclage during the study period. Inclusion criteria required a cervix length of ≤25 mm as measured via transvaginal sonography in the second trimester or the presence of prolapsed membranes. Singleton and multiple pregnancies, irrespective of chorionicity, parity, previous preterm labor, or mode of conception, were included, with twin pregnancies representing the only form of multiple pregnancy in this cohort. Cerclage was not performed in cases with PROM (premature rupture of membranes), uterine contractions, vaginal bleeding, or suspected infection. Premature rupture of membranes was excluded using the Actim® PROM test (Actim Oy, a part of Medix Biochemica Oy, Espoo, Finland). Exclusion due to suspected infection was based on clinical indicators, such as fever, vaginal pH > 5, elevated leukocytes and/or increased C-reactive protein.

All patients received standardized adjunct therapy, including antibiotics according to the antibiogram obtained from a vaginal smear or empirical penicillin if no antibiogram was available. In cases with a positive cervical smear (testing for Chlamydia, Mycoplasma, or Ureaplasma), a single dose of azithromycin was administered. Additionally, tocolytic therapy with indomethacin 100 mg every 8–12 h for 48 h was initiated, or with nifedipine if the gestational age exceeded 26 weeks. The surgical procedure was performed under spinal anesthesia. Beginning two days postoperatively, all patients received progesterone 200 mg once daily, as well as Vagiflor^® every other day until cerclage removal. Patients were instructed to return every two weeks for vaginal disinfection using Octenisept^®. These adjunct therapies were applied uniformly across singleton and multiple pregnancies.

Patients meeting the inclusion criteria were identified from the clinic’s operating records. Each patient’s information was anonymized to ensure confidentiality, resulting in a final sample of 96 participants. Parameters analyzed in this study were derived from inpatient and outpatient records and retrospectively extracted from the hospital’s electronic documentation systems.

Data points comprised baseline characteristics (demographic and anthropometric details), cervical length measurements, presence of prolapsed membranes, as well as gestational age at cerclage placement and removal. Obstetric history comprised parity, gravidity, and any history of previous preterm birth or late miscarriage.

Primary outcome measures were pregnancy outcomes, including term delivery rates (>37 + 0 weeks), gestational age at birth, and mode of delivery. Pregnancy loss with a birth weight below 500 g was documented as miscarriage. Perinatal mortality was defined as stillbirth (≥500 g) or death within the first seven days postpartum. Fetal parameters further included birth weight and the diagnosis of neonatal infections.

Secondary outcomes focused on surgical complications, defined as uterine contractions, PROM, vaginal bleeding exceeding the expected postoperative amount, maternal infection (clinical signs or rising inflammatory markers requiring antibiotic therapy), and suture failure (renewed prolapse of membranes). Complications were documented if they occurred perioperatively or within 7 days following cerclage placement. Additionally, the need for continued postoperative inpatient care, rehospitalization due to threatened preterm labor, and complications during cerclage removal (incomplete or uncertain suture removal) were recorded.

To assess baseline comparability for the subsequent outcome analyses, patient characteristics were also compared between singleton and multiple pregnancies. Statistical analyses were conducted using both descriptive and inferential methods. For continuous variables, the mean, standard deviation, median, and interquartile range (IQR) were reported as appropriate. Categorical data were analyzed using the Chi-square or Fisher’s exact test for nominal variables, while the Wilcoxon rank-sum test was used for continuous, non-parametric data. Statistical significance was set at p < 0.05.

3. Results

This study included 96 women who underwent second-trimester cerclage, of whom 79 had singleton pregnancies and 17 had multiple pregnancies. The mean maternal age was 31.7 years (SD 4.8), with a BMI of 28 kg/m² (SD 7). The median cervical length before cerclage was 14 mm (IQR 9–18 mm). At the time of cerclage placement, prolapsed membranes were documented in 33% of patients. Cerclage was performed at a median gestational age of 157 days (IQR 144–175) and did not differ between singleton and multiple pregnancies (156 days, IQR 142–176 vs. 169 days, IQR 156–173; p = 0.3). Comparative analysis of all other patient characteristics further showed no significant differences between the groups, except for gestational age at cerclage removal, which was slightly earlier in multiple pregnancies (241 days, IQR 204–250 vs. 250 days, IQR 238–254; p = 0.047). All patient characteristics are demonstrated in

Table 1. Patient characteristics.

Characteristic	N = 96 1
Age (years)	96
Mean (SD)		31.7 (4.8)
Median (Q1–Q3)		32.0 (29.0–35.0)
Weight (kg)	96
Mean (SD)		79 (20)
Median (Q1–Q3)		73 (65–88)
BMI	96
Mean (SD)		28 (7)
Median (Q1–Q3)		26 (24–33)
Gravida	96	2.00 (1.00–3.00)
Para	96	1.00 (1.00–2.00)
Singleton/Multiple pregnancies	96
Singleton pregnancy		79 (82%)
Multiple pregnancy		17 (18%)
History of Preterm Birth or Late Miscarriage	96	22 (23%)
Cervical Length (mm)	86
Mean (SD)		14 (6)
Median (Q1–Q3)		14 (9–18)
Membrane Prolapse	96	32 (33%)
Gestational age (days) at Cerclage Surgery	96
Mean (SD)		158 (22)
Median (Q1–Q3)		157 (144–175)
Gestational age (days) at Cerclage Removal	91
Mean (SD)		237 (29)
Median (Q1–Q3)		249 (233–253)

With 4 multiple pregnancies, the cerclage is only placed after the miscarriage of a child. ¹ Median (Q1–Q3); n (%).

, the comparative analysis is presented in

Table 2. Patient characteristics—comparative analysis.

Characteristic	N	Singleton Pregnancies N = 79 1	Multiple Pregnancies N = 17 1	p-Value
Age (years)	96			0.3 2
Mean (SD)		31.4 (4.3)	33.0 (6.6)
Median (Q1–Q3)		32.0 (29.0–35.0)	34.0 (29.0–37.0)
Weight (kg)	96			0.7 2
Mean (SD)		79 (21)	80 (19)
Median (Q1–Q3)		73 (65–88)	72 (65–96)
BMI	96			0.5 2
Mean (SD)		28 (7)	29 (6)
Median (Q1–Q3)		26 (24–33)	28 (24–33)
Gravida	96	2.00 (1.00–3.00)	1.00 (1.00–2.00)	0.2 2
Para	96	1.00 (1.00–2.00)	1.00 (1.00–2.00)	0.7 2
History of Preterm Birth or Late Miscarriage	96	18 (23%)	4 (24%)	>0.9 3
Cervical Length (mm)	86			0.12 2
Mean (SD)		14 (6)	11 (6)
Median (Q1–Q3)		15 (9–18)	13 (5–17)
Membrane Prolapse	96	26 (33%)	6 (35%)	0.9 4
Gestational age (days) at Cerclage Surgery	96			0.3 2
Mean (SD)		157 (23)	164 (17)
Median (Q1–Q3)		156 (142–176)	169 (156–173)
Gestational age (days) at Cerclage Removal	91			0.047 2
Mean (SD)		239 (29)	228 (27)
Median (Q1–Q3)		250 (238–254)	241 (204–250)

With 4 multiple pregnancies, the cerclage is only placed after the miscarriage of a child. ¹ Median (Q1–Q3); n (%). ² Wilcoxon rank sum test. ³ Fisher’s exact test. ⁴ Pearson’s Chi-squared test.

.

Pregnancy outcomes are demonstrated in

Table 3. Pregnancy outcomes.

Characteristic	N	Singleton Pregnancies N = 79 1	Multiple Pregnancies N = 17 1	p-Value
Term Birth (>37 + 0 weeks)	96	43 (54%)	3 (18%)	0.006 2
Gestational age (days) at birth	93			<0.001 4
Mean (SD)		258 (25)	228 (28)
Median (Q1–Q3)		263 (247–277)	243 (201–250)
Miscarriage	96	3 (3.8%)	0 (0%)	>0.9 3
Caesarean section	93	25 (33%)	14 (82%)	<0.001 2
Primary/Secondary Caesarean section	38			0.7 3
Primary		4 (16%)	3 (23%)
Secondary		21 (84%)	10 (77%)

With 4 multiple pregnancies, the cerclage is only placed after the miscarriage of a child. ¹ n (%). ² Pearson’s Chi-squared test. ³ Fisher’s exact test. ⁴ Wilcoxon rank sum test.

and

Table 4. Pregnancy outcomes—fetal parameters.

Characteristic	N	Singletons N = 79 1	Multiples N = 17 1	p-Value
Perinatal Mortality	106	2 (2.6%)	1 (3.3%)	>0.9 2
Neonatal Infection	106	20 (26%)	16 (53%)	0.008 3
Birth Weight (g)	106			<0.001 4
Mean (SD)		2823 (774)	2021 (749)
Median (Q1–Q3)		2943 (2390–3380)	1985 (1240–2670)

With 4 multiple pregnancies, the cerclage is only placed after the miscarriage of a child. ¹ n (%). ² Fisher’s exact test. ³ Pearson’s Chi-squared test. ⁴ Wilcoxon rank sum test.

, with significant differences observed between singleton and multiple pregnancies. Term birth rates were lower in multiples (18% vs. 54%, p = 0.006). Similarly, the mean gestational age at birth was reduced in multiples compared with singleton pregnancies (228 days, SD 28 vs. 258 days, SD 25; p < 0.001). Caesarean sections were performed more frequently in multiple pregnancies (82% vs. 37%, p < 0.001). No difference was observed in the incidence of second-trimester miscarriage after cerclage placement, with 3.8% in singleton pregnancies and no cases in multiple pregnancies (p > 0.9). Among fetal parameters, birth weight was significantly lower in multiples (median 1985 g, IQR 1240–2670) compared with singletons (median 2943 g, IQR 2390–3380; p < 0.001). Neonatal infections were more common in multiples (53% vs. 20%, p = 0.008), whereas perinatal mortality did not differ significantly between groups, with only two documented cases in singletons (2.6%) and one in multiples (3.3%; p > 0.9).

Except for post-cerclage labor activity or contractions, which was significantly more frequent in multiple pregnancies (24% vs. 5.1%, p = 0.031), surgical complications did not differ significantly between groups. Post-cerclage vaginal bleeding occurred in 11% of singleton pregnancies and none in multiples (p = 0.4). PROM was observed in 2.5% of singleton pregnancies, with no cases in multiples (p > 0.9). Maternal infection rates were higher in multiple pregnancies (12%) compared to singletons (3.8%), although this difference was not statistically significant (p = 0.2). Cases in which exclusively postoperative outpatient management was not possible—due to continued inpatient care or rehospitalization—were similar between singleton and multiple pregnancies (27% vs. 28%, p = 0.8). However, among rehospitalized patients, gestational age at rehospitalization was significantly lower in multiples (151 days, SD 14 vs. 208 days, SD 28; p = 0.048). All complications are presented in

Table 5. Complications.

Characteristic	N	Singleton Pregnancies N = 79 1	Multiple Pregnancies N = 17 1	p-Value
Uterine Contractions	96	4 (5.1%)	4 (24%)	0.031 2
PROM (Premature Rupture of Membranes)	96	2 (2.5%)	0 (0%)	>0.9 2
Vaginal bleeding	96	9 (11%)	0 (0%)	0.4 2
Maternal Infection	96	3 (3.8%)	2 (12%)	0.2 2
Suture Failure	96	2 (2.5%)	0 (0%)	>0.9 2
Complications of Cerclage Removal	91	9 (12%)	0 (0%)	0.4 2
Rehospitalization/Inpatient Management	96	21 (27%)	5 (29%)	0.8 2
Gestational Age at Rehospitalization in Days	21			0.048 3
Mean (SD)		208 (28)	151 (14)
Median (Q1–Q3)		214 (194–233)	151 (141–161)

With 4 multiple pregnancies, the cerclage is only placed after the miscarriage of a child. ¹ n (%). ² Fisher’s exact test. ³ Wilcoxon rank sum test.

.

4. Discussion

This study provides a detailed comparative analysis of the impact of second-trimester cervical cerclage on pregnancy outcomes in singleton and multiple pregnancies with cervical shortening, offering insights into efficacy and clinical implications.

Our data indicate that cerclage is less effective in preventing preterm birth < 37 + 0 weeks in multiple pregnancies (18% term births) compared with singleton pregnancies (54% term births). This finding aligns with prior studies showing limited benefit in multifetal gestations, which inherently carry higher risks for premature cervical dilation and preterm labor due to greater uterine strain [8,10]. Taken together, the reduced effectiveness of cerclage in multiple pregnancies may be explained by increased uterine distension, higher mechanical cervical stress, and inflammatory pathways that cannot be fully compensated by a purely mechanical intervention. When comparing our results to the findings of Oberdorfer et al., who analyzed physiological multiple pregnancies that did not require cerclage placement, notable differences emerge in parameters such as birth weight and gestational age at delivery—both of which significantly influence pregnancy outcomes. In the Oberdorfer et al. study, the median birth weight among multiple pregnancies (including both mono- and dichorionic twins) ranged from 2280 g to 2400 g, whereas in our cohort of post-cerclage twin pregnancies, the median birth weight was only 2021 g. Similarly, gestational age at delivery differed markedly: post-cerclage pregnancies delivered at approximately 228 days, compared with 251.5–256.0 days in multiple pregnancies without cerclage. These findings highlight the substantial impact of cerclage-requiring conditions, particularly on gestational duration [16].

Nevertheless, the equally low incidence of second-trimester miscarriage after cerclage placement, with 3 cases in singleton and none in multiple pregnancies, suggests a stabilizing effect in both groups that likely contributes to the prevention of pregnancy loss due to cervical insufficiency.

Other outcome parameters further illustrate differences between groups. Caesarean section rates were higher in multiple pregnancies (82%) compared with singleton pregnancies (33%), which is consistent with published data. In Germany, the average caesarean delivery rate across all births is approximately 32%, whereas in twin pregnancies it increases substantially to around 76% [1]. Although women with a shortened cervix represent a high-risk population for preterm birth and related maternal, fetal, and intrapartum complications that may indicate caesarean delivery, the caesarean rate was comparable to the general obstetric population for singleton pregnancies and like that of unselected twin pregnancies for multiple pregnancies. This supports the assumption that cerclage does not influence decisions concerning the mode of delivery. The higher cesarean section rate observed in multiple pregnancies most likely reflects standard obstetric management and institutional practice for multifetal gestations rather than an effect of cerclage placement.

The lower birth weight in multiples (median 1985 g vs. 2943 g) reflects both their earlier gestational age at delivery (mean 228 vs. 258 days in singletons) and a physiologically slower intrauterine growth trajectory compared to singletons, which can be mainly attributed to uterine capacity and placental limitations.

A markedly higher rate of neonatal infections was observed in multiples (53% vs. 26%). This is most likely attributable to significantly earlier birth (mean gestational age 228 vs. 258 days), as prematurity is a well-established risk factor for neonatal infections due to immunologic immaturity, underdeveloped epithelial barriers, and delayed colonization by protective microbiota [17,18]. In addition, premature infants—particularly those from multiple pregnancies—often require invasive neonatal interventions, such as mechanical ventilation or central venous catheter placement, which further increase infection risk [19]. Thus, the elevated infection rate in twins in this high-risk cohort appears to reflect both gestational immaturity and structural risk factors related to multifetal gestation as well as the indication for cerclage. Yet, perinatal mortality remained low and comparable (2.6% in singletons vs. 3.3% in multiples), suggesting that cerclage may contribute similarly to preventing severe neonatal outcomes in both groups. Given the small number of perinatal deaths observed, any potential association between cerclage and perinatal mortality should be interpreted with caution and regarded as exploratory and hypothesis-generating. Consistent with our findings, a recent multicenter study by He et al. (2025) further showed that cerclage reduced perinatal mortality more effectively than other preventive strategies in high-risk pregnancies with marked cervical shortening—an outcome particularly critical in patients at imminent risk of extreme prematurity [20]. Together, these data underscore the clinical relevance of cerclage in preventing severe preterm-related neonatal outcomes leading to perinatal death. However, confirmation in larger prospective trials remains essential.

Regarding secondary outcomes, the higher incidence of postoperative preterm contractions observed in multiple pregnancies (24% vs. 5.1%) likely reflects a combination of mechanical, inflammatory, and procedural factors. Uterine overdistension inherent to twin gestations increases myometrial stretch, which stimulates prostaglandin release and lowers the contraction threshold, predisposing to early labor onset [21]. Furthermore, cervical insufficiency in the context of a multifetal pregnancy contributes to an unstable biomechanical environment, where even a well-placed cerclage may not fully compensate for progressive cervical stress. Membrane prolapse prior to cerclage placement, more frequently observed in this cohort, can further exacerbate irritation at the internal cervical os, triggering uterine activity. Additionally, subclinical intrauterine inflammation or infection—common in cases of advanced cervical shortening—may amplify the risk of uterine contractions by prompting the release of cytokines and proinflammatory mediators [22]. Lastly, the timing of cerclage placement appears to play a critical role. Interventions performed late in cervical shortening or under acute mechanical strain may inadvertently provoke uterine irritability or local inflammatory responses, particularly in the sensitive context of multiple gestation. Collectively, these findings highlight the multifactorial nature of post-interventional preterm contractions and the complexity of managing cervical insufficiency in multifetal gestation and imply that adjunctive anti-inflammatory or tocolytic strategies may be necessary to reduce contraction-related complications.

A noteworthy aspect of the study is the focus on the feasibility of postoperative outpatient management, a critical yet underreported outcome. Robust data on rehospitalization rates are currently lacking, making it difficult to assess the broader impact of second-trimester cerclage on maternal quality of life. Recurrent hospital admissions can disrupt daily routines, increase psychological stress, and impose economic and logistical burdens on expectant mothers. Reliable data on rehospitalization rates could help set realistic expectations and support individualized care planning, especially for women with multiple pregnancies, who already face a higher risk of pregnancy complications.

In our cohort, the need for postoperative continued inpatient care or rehospitalization was similar between singleton and multiple pregnancies (27% vs. 29%), suggesting a clinically stabilizing effect of cerclage in both groups. This finding indicates that most women—irrespective of singleton or multiple gestation—were able to continue outpatient care from cerclage placement until removal and delivery, thereby reducing further hospital stay. Such a potential positive impact on maternal quality of life and healthcare resource utilization should not be overlooked, as rehospitalization due to threatened labor represents a considerable emotional and economic burden.

Besides the higher incidence of postoperative uterine contractions in multiple pregnancies, not only rehospitalizations but all other cerclage-associated complications were comparable between the groups—including preterm contractions and vaginal bleeding within the first 7 days postoperative. Beyond this early period, only 13 of the documented rehospitalizations were attributable to these same parameters: manifest preterm contractions (6 cases), PROM (5 cases), and vaginal bleeding (2 cases).

In summary, second-trimester cerclage appears to prevent pregnancy complications that lead to hospitalization in multiple pregnancies to the same extent as in singletons. Future studies should aim to quantify these impacts more precisely and include patient-reported outcomes to better assess the broader psychosocial implications of cerclage for maternal well-being. Enhanced data on rehospitalization could improve clinical guidance and counseling practices, enabling healthcare providers to fully inform patients of the potential benefits and risks associated with the procedure and to optimize psychosocial and physical support systems.

A key strength of this study is its clear comparative focus on singleton and multiple pregnancies following second-trimester cerclage, a topic for which high-quality data is limited. Conducted at a tertiary care center with standardized clinical protocols, the study ensured consistency in the indication, placement, and follow-up of cerclage procedures. The inclusion of a well-characterized patient cohort, along with detailed outcome data—including surgical complications and neonatal parameters—provides valuable insights into the comparative efficacy and limitations of cervical cerclage in diverse obstetric populations with a short second-trimester cervical length. Moreover, this study provides novel data on the feasibility of outpatient management and rehospitalization following cerclage placement, which is essential for evaluating the broader impact of cerclage on maternal quality of life, an aspect that has so far been insufficiently addressed.

However, several limitations must be acknowledged. Most notably, the relatively small sample size—particularly within the multiple pregnancy subgroup—limits the statistical power to detect more subtle differences and restricts the generalizability of subgroup analyses. Multivariable modeling was not performed due to the limited sample size of the multiple pregnancy group, as adjusted analyses would have resulted in unstable and potentially misleading estimates. The retrospective design inherently limits causal inference and is subject to potential documentation bias. In particular, the retrospective design and the imbalance in sample size between singleton and multiple pregnancies (79 vs. 17) further limit causal inference and generalizability. A prospective or randomized study design was not feasible due to ethical and practical considerations, as second-trimester cerclage is typically performed as an urgent intervention in women with advanced cervical shortening or prolapsed membranes. Due to the limited sample size of the multiple pregnancy group, confidence intervals were not reported, as they would have been wide and of limited interpretative value. The absence of a matched control group without cerclage prevents definitive conclusions regarding the comparative efficacy of cerclage versus conservative management or alternative interventions such as pessary or progesterone therapy. The inclusion of cases in which cerclage was placed after loss of one fetus may have introduced additional heterogeneity and should be considered when interpreting the results. Chorionicity was not systematically available in this retrospective cohort and could therefore not be included in the analysis, which represents an additional limitation given its prognostic relevance in twin pregnancies. Finally, patient-reported outcomes—including psychological burden and satisfaction with care—were not assessed and should be a focus of future research. Although adjunct therapies were applied according to a standardized protocol, the sample size did not allow meaningful subgroup analyses to evaluate potential effect modification.

5. Clinical Implications and Practice Recommendations

Clinicians should counsel patients with multiple pregnancies that second-trimester cerclage is less effective in preventing preterm birth compared to singleton pregnancies. Nevertheless, cerclage may provide a stabilizing effect in selected high-risk cases. Individualized management strategies, including close monitoring and adjunct therapies, should therefore be considered for multifetal gestations. In multiple pregnancies, the decision to perform second-trimester cerclage should be based on individual risk factors such as pronounced cervical shortening, cervical dilation with exposed membranes, obstetric history, and gestational age at presentation. Importantly, the potential for outpatient management and avoidance of prolonged hospitalization should be addressed during patient counseling to support shared decision-making and maternal quality of life.

6. Conclusions

This study shows that second-trimester cerclage is less effective in preventing preterm birth < 37 + 0 weeks in multiple pregnancies compared to singleton pregnancies. Multiples remain associated with lower gestational age at birth and birth weight, as well as higher rates of caesarean section, neonatal infections, and uterine irritability despite intervention. Nevertheless, similar rehospitalization rates between singleton and multiple pregnancies suggest a stabilizing effect on pregnancy, sufficiently reducing hospital stay and enabling outpatient management after cerclage placement in both groups. Our findings highlight the need for individualized risk assessment and treatment planning, particularly in multifetal gestations given their inherent risks. Future prospective studies with larger cohorts and appropriate control groups are essential to validate these results and to comprehensively evaluate the patient-centered impact of cerclage, thereby refining clinical guidelines for different obstetric populations.