Development and validation of a nomogram to predict spontaneous preterm birth in singleton gestation with short cervix and no history of spontaneous preterm birth

Background

Spontaneous preterm birth (sPTB) stands as a leading cause of neonatal mortality. Consequently, preventing sPTB has emerged as a paramount concern in healthcare. Therefore, our study aimed to develop a nomogram, encompassing patient characteristics and cervical elastography, to predict sPTB in singleton pregnancies. Specifically, we targeted those with a short cervix length (CL), no history of sPTB, and who were receiving vaginal progesterone therapy.

Methods

A total of 568 patients were included in this study. Data from 392 patients, collected between January 2016 and October 2019, constituted the training cohort. Meanwhile, records from 176 patients, spanning November 2019 to January 2022, formed the validation cohort. Following the univariate logistic regression analysis, variables exhibiting a P-value less than 0.05 were integrated into a multivariable logistic regression analysis. The primary objective of this subsequent analysis was to identify the independent predictors linked to sPTB in the training cohort. Next, we formulated a nomogram utilizing the identified independent predictors. This tool was designed to estimate the likelihood of sPTB in singleton pregnancies, particularly those with a short CL, devoid of any sPTB history, and undergoing vaginal progesterone therapy. The C-index, Hosmer-Lemeshow (HL) test, calibration curves, decision curve analysis (DCA), and receiver operating characteristic (ROC) were used to validate the performance of the nomogram.

Results

Upon finalizing the univariate analysis, we progressed to a multivariable analysis, integrating 8 variables with P < 0.05 from the univariate analysis. The multivariable analysis identified 7 independent risk factors: maternal age (OR = 1.072; P < 0.001), cervical length (OR = 0.854; P < 0.001), uterine curettage (OR = 7.208; P < 0.001), GDM (OR = 3.570; P = 0.006), HDP (OR = 4.661; P = 0.003), C-reactive protein (OR = 1.138; P < 0.001), and strain of AI (OR = 7.985; P < 0.001). The nomogram, tailored for sPTB prediction, was grounded on these 7 independent predictors. In predicting sPTB, the C-indices manifested as 0.873 (95% CI, 0.827-0.918) for the training cohort and 0.916 (95%CI, 0.870-0.962) for the validation cohorts, underscoring a good discrimination of the model. Additionally, the ROC curves served to evaluate the discrimination of nomogram model across both cohorts. Calibration curves were delineated, revealing no statistically significant differences in both the training (χ2 = 5.355; P = 0.719) and validation (χ2 = 2.708; P = 0.951) cohorts as evidenced by the HL tests. Furthermore, the DCA underscored the model's excellence as a predictive tool for sPTB.

Conclusions

By amalgamating patient characteristics and cervical elastography data from the second trimester, the nomogram emerged as a visually intuitive and dependable tool for predicting sPTB. Its relevance was particularly pronounced for singleton pregnancies characterized by a short CL, an absence of prior sPTB incidents, and those receiving vaginal progesterone therapy.

Cytokine quantification and association with cervical length in a prospective cohort of pregnant women

BACKGROUND

Preterm birth is a leading cause of infant morbidity and mortality; its multifactorial causes are an obstacle to understanding etiology and pathogenesis. The importance of cytokines and inflammation in its etiology and association with the short cervix is nowadays well-proven. To date, there are no reliable biological or biochemical markers to predict preterm birth; even though the length of the cervix has high specificity, its sensitivity with the cervix below 2.5 cm is low.

OBJECTIVE

We study the association of plasma cytokine levels and cervical length in search of predictors of preterm birth.

STUDY DESIGN

We evaluated a total of 1400 pregnant women carrying a single fetus between 20 and 25 weeks of gestation, and 1370 of them after childbirth in a nested case-control study of a prenatal cohort. Eligible pregnant women were interviewed and submitted to obstetric morphological and transvaginal ultrasound with cervical length measurement, gynecological examination, and blood collection. Preterm birth occurred in 133 women, 129 included in the study, and a control group randomly selected at a 2:1 ratio. A total of 41 cytokines with a higher probability of being associated with preterm birth or being of significance during labor were determined.

RESULTS

Cytokine and cervical length analysis by multivariate analysis of the conditional interference tree revealed that growth-related oncogene values of less than 2293 pg/mL were significantly associated with a cervical length of less than 2.5 cm.

CONCLUSIONS

As well as a cervical length shorter than 2.5 cm, growth-related oncogene levels of less than 2293 pg/ml may be associated with an increased risk of PB. Analysis based on the association of biomarkers and of the interaction between cytokines is a promising pathway in search of a predictor of preterm birth.

Association between cervical length and gestational age at birth in singleton pregnancies: a multicentric prospective cohort study in the Brazilian population

BACKGROUND

Short cervical length measured during the second trimester of pregnancy is an important risk factor for spontaneous preterm birth (sPTB). The aim of this study is to identify the association between mid-pregnancy cervical length (CL) and gestational age at birth in asymptomatic singleton pregnant women.

METHODS

This is a prospective cohort study involving singleton pregnant women who participated in the screening phase of a Brazilian multicenter randomized controlled trial (P5 trial) between July 2015 and March 2019. Transvaginal ultrasound to measure CL was performed from 18 to 22 + 6 weeks. Women with CL ≤ 30 mm received vaginal progesterone (200 mg/day) until 36 weeks' gestation. For this analysis we considered all women with CL ≤ 30 mm receiving progesterone and a random selection of women with CL > 30 mm, keeping the populational distribution of CL. We obtained prognostic effectiveness data (area under receive operating characteristic curve (AUC), sensitivity and specificity and estimated Kaplan-Meier curves for preterm birth using different CL cutoff points.

RESULTS

We report on 3139 women and identified a negative association between cervical length and sPTB. CL ≤ 25 mm was associated with sPTB < 28, sPTB < 34 and sPTB < 37 weeks, whereas a CL 25-30 mm was directly associated with late sPTB. CL by transvaginal ultrasound presented an AUC of 0.82 to predict sPTB < 28 weeks and 0.67 for sPTB < 34 weeks. Almost half of the sPTB occurred in nulliparous women and CL ≤ 30 mm was associated with sPTB at < 37 weeks (OR = 7.84; 95%CI = 5.5-11.1). The number needed to screen to detect one sPTB < 34 weeks in women with CL ≤ 25 mm is 121 and we estimated that 248 screening tests are necessary to prevent one sPTB < 34 weeks using progesterone prophylaxis.

CONCLUSIONS

CL measured by transvaginal ultrasound should be used to predict sPTB < 34 weeks. Women with CL ≤ 30 mm are at increased risk for late sPTB.

Cerclage versus vaginal progesterone in low-risk pregnant women with a short cervix

OBJECTIVE

To compare vaginal progesterone to cerclage in preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, incidentally found sonographic cervical length of <15 mm, and no history of preterm birth.

STUDY DESIGN

A retrospective cohort study was conducted on 68 women who delivered at the University of Kansas Health System with a singleton gestation found to have a cervical length <15 mm on transvaginal ultrasound and no history of preterm birth. Women treated with vaginal progesterone (n = 29) were compared to women who underwent cerclage placement (n = 39). The primary outcome was preterm birth at <34 weeks of gestation. Secondary outcomes include preterm birth at <37 and <28 weeks of gestation and neonatal morbidities.

RESULTS

Of the 268 patients who had a cervical length of <15 mm on transvaginal ultrasound, 68 participants met inclusion criteria and were included in the final analysis. Twenty-nine participants received vaginal progesterone and 39 participants received cervical cerclage. The average cervical length at initiation of therapy was greater in the progesterone cohort versus cerclage cohort, respectively (10.5 vs. 8.0 mm, p < .01). All other baseline characteristics were similar between groups, including no difference in average gestational age at initiation of therapy (21.6 vs. 21.5 weeks, p = .87). Average latency after therapy did not differ between groups (100 vs. 92.7 days p = .43). The incidence of preterm birth at <37 weeks (OR = 1.49, 95% CI = 0.57-3.93), <34 weeks (OR = 1.47, 95% CI = 0.52-4.18), and <28 weeks (OR = 1.90, 95% CI = 0.45-8.07), did not differ significantly between groups. Additionally, no difference in neonatal morbidity was detected.

CONCLUSION

At our institution, we found no difference between vaginal progesterone and cerclage in the average latency period or risk of preterm birth among women with an incidental short cervix of <15 mm and no history of preterm birth, despite the significantly shorter initial cervical length in the cerclage group. These findings suggest either vaginal progesterone or cerclage could be used to reduce the risk of preterm birth among this high-risk population.

Timing of antenatal corticosteroids in relation to clinical indication

PURPOSE

This study aimed at determining the proportion of women who receive antenatal corticosteroids (ACS) within the optimal time window before birth based on the indication for ACS, and to explore in more detail indications that are associated with suboptimal timing.

METHODS

A retrospective cohort study of all women who received ACS in a single tertiary center between 2014 and 2017. The primary outcome was an ACS-to-birth interval ≤ 7 days. Secondary outcomes were ACS-to-birth interval of ≤ 14 days, and the proportion women who received ACS but ultimately gave birth at term (≥ 37^0/7 weeks). The study outcomes were stratified by the clinical indication for ACS.

RESULTS

A total of 1261 women met the study criteria, of whom 401 (31.8%) and 569 (45.1%) received ACS within ≤ 7 days and ≤ 14 days before birth, respectively, and 203 (16.1%) ultimately gave birth at term. The proportion of women who received ACS within 7 days before birth was highest for women with preeclampsia (50.4%), and was lowest for women with an incidental finding of a short cervix (8.4%). In the subgroup of women with an incidental finding of a short cervix, the likelihood of optimal timing was not related to the magnitude of cervical shortening, history of preterm birth, multifetal gestation, presence of cervical funneling, or the presence of cervical cerclage.

CONCLUSION

Over two-thirds of infants who are exposed to ACS do not get the maximal benefit from this intervention. The current study identified clinical indications for ACS that are associated with suboptimal timing of ACS where more research is needed to develop quantitative, indication-specific prediction models to guide the timing of ACS.

Identifying the associated factors with onset of preterm PROM compared with term PROM - A retrospective cross-sectional study

OBJECTIVE

To determine the risk factors associated with the preterm premature rupture of membranes (p-PROM).

MATERIALS AND METHODS

This retrospective cross-sectional study assessed 110 p-PROM cases from among 6642 deliveries at a Japanese perinatal medical center, from June 2016 to September 2018. The control group comprised 220 term PROM (t-PROM) cases. We excluded cases with artificial PROM or rupture of membranes after labor, those with multiple pregnancies, those with p-PROM at 36 weeks and those with t-PROM at 37 weeks. In order to compare p-PROM with t-PROM, univariate and multivariate analysis were performed using several clinical factors at the time of PROM onset.

RESULTS

The p-PROM group included 110 cases with 14-35 weeks PROM, and the t-PROM group included 220 cases with 38-41 weeks PROM. Eleven factors were identified as significant factors on the univariate analysis. A history of cervical conization (OR 37.5, 95% CI: 2.31-607.1), cervical length <25 mm at 28 weeks (OR 9.31, 95% CI: 1.76-49.3), negative Lactobacillus (OR 4.01, 95% CI: 1.18-13.7), and bleeding during the second trimester (OR 3.35, 95% CI: 1.18-9.53) were identified as significant factors by the multivariate analysis. Based on the risk factors identified during the multivariate analysis, we divided the 330 cases in the following three groups: 0 group (n = 244), 1 group (n = 60), and 2-4 group (n = 26). The ratio of p-PROM:t-PROM was calculated and compared for each group. The ratios were 21% (0 group), 57% (1 group), and 100% (2-4 group), indicating statistically significant differences between the groups (p < 0.001).

CONCLUSION

We found that the following four factors were associated with p-PROM: history of cervical conization, cervical length <25 mm at 28 weeks, negative Lactobacillus, and bleeding during the second trimester. Our results suggest that we can identify patients who are at increased risk for p-PROM, based on these factors. Further research is necessary to determine the optimal treatment approach for these patients to prevent p-PROM.

Preoperative Cervical Length Predicts the Risk of Delivery within One Week after Pleuroamniotic Shunt in Fetuses with Severe Hydrothorax

OBJECTIVE

The objective of this study was to assess the predictive performance of preoperative cervical length (CL) for delivery within 1 week after pleuroamniotic shunting (PAS) in fetuses with severe hydrothorax.

METHODS

A prospective cohort of fetuses with severe hydrothorax referred to our fetal surgery center in Querétaro, Mexico from January 2012 to July 2020. Severe fetal hydrothorax was diagnosed as an accumulation of fluid within the fetal pleural space accompanied with severe bilateral lung compression, mediastinal shift, polyhydramnios, and/or hydrops. Transvaginal CL was measured immediately before PAS, and a short cervix was defined as that <25 mm. The interval from fetal intervention to delivery, prevalence of preterm prelabor rupture of membranes (PPROMs), and associations with delivery within the first week after PAS according to a short or a normal CL, were evaluated.

RESULTS

Thirty-five pregnancies with severe fetal hydrothorax treated with PAS were evaluated. Median gestational age at PAS was (weeks + days) 31+2 (range, 26+0-36+1). Two (5.7%) and 7 (20.0%) cases delivered within the first 24 h and 1 week after PAS, respectively. Ten (28.6%) women had a short cervix before PAS, while 25 (71.4%) had normal preoperative CL. Women with a short cervix showed lower mean interval between fetal intervention and delivery (2.4 vs. 5.5 weeks, p = 0.01), and higher prevalence of PPROM (50 vs. 12%, p = 0.01), as compared to women with a nonshort cervix. Preoperative short cervix was associated with significantly higher risk of delivery within the first 24 h (20.0 vs. 0%, respectively, p < 0.05) and 1 week after PAS (50.0 vs. 8.0%, respectively, p < 0.01) compared with pregnancies with normal preoperative CL.

CONCLUSION

In pregnancies with severe fetal hydrothorax candidates for pleuroamniotic shunt, identification of a short cervix before fetal intervention can predict delivery within 1 week after the surgical procedure.

The Short Cervix: A Critical Analysis of Diagnosis and Treatment

A short cervix in the second trimester is a significant risk factor for spontaneous preterm birth, preterm prelabor rupture of membranes, and subsequent adverse perinatal outcome. The pathophysiology is complex and multifactorial with inflammatory and/or infectious processes often involved. Biomarkers have been developed in an effort to predict preterm birth with varying degrees of success. The treatment options of cerclage, progesterone, pessary, and combination therapy are reviewed. Evidence-based protocols are summarized for singleton and multiple gestation.

Does Assessment of Cervical Phosphorylated Insulin-like Growth Factor Binding Protein-1 by Bedside Vaginal Swab Test Really Predict Preterm Birth?

Preterm birth is the first cause of neonatal mortality and is associated with elevated risks of long-term complications such as neurodevelopmental impairment. Prediction of spontaneous preterm birth, one of the biggest challenges in obstetrics, aims at delaying birth in order to allow corticosteroid therapy and, if necessary, transfer of patient to a higher-level maternity care unit. We aimed to assess the predictive role of phIGFBP-1 (Actim® Partus) diagnostic test on patients at risk of preterm labor, routinely used in our institution. We conducted a retrospective cohort study on 99 patients admitted in the high-risk pregnancy unit of our institution from June 2012 to November 2014. The primary outcome measures were delivery before 34⁺⁰ and 37⁺⁰ weeks. Data analysis allowed measure of Actim® Partus test sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV), diagnostic efficiency as well as positive and negative likelihood ratios. Actim® Partus test features (Se, Sp, PPV and NPV) were 53.3, 67.9, 23.5 and 88.7% respectively for deliveries occurring ≤ 34⁺⁰ weeks and 54.2, 75.4, 55.8, and 74.2%, respectively, for deliveries occurring ≤ 37⁺⁰ weeks. Diagnostic efficiency of the test was 65.7% (≤ 34⁺⁰ weeks) and 67.7% (≤ 37⁺⁰ weeks). Positive likelihood ratios were 1.6 (≤ 34⁺⁰ weeks) and 2.2 (≤ 37⁺⁰ weeks). Negative likelihood ratios were 0.7 (≤ 34⁺⁰ weeks) and 0.6 (≤ 37⁺⁰ weeks). Results of our study show that phIGFBP-1 diagnostic test is not accurate enough in predicting preterm birth before 34⁺⁰ or 37⁺⁰ weeks, and therefore, there is little clinical interest in its everyday use.

A new quantification system for assessing the degree of acute cervical insufficiency based on physical and sonographic examination

OBJECTIVES

Acute cervical insufficiency accounts for 10-25 % of all mid-trimester pregnancy losses. However, the definition and description for the degree of acute cervical insufficiency were obscure and different among the many studies. The aim of this study was to suggest a new 4-digit quantification system and to evaluate the outcome according to the new system in women with acute cervical insufficiency.

STUDY DESIGN

A retrospective cohort study was conducted in patients with acute cervical insufficiency who underwent physical examination indicated cervical cerclage. Acute cervical insufficiency was defined as painless external os dilation with prolapsed and/or visible membranes on speculum examination. The status of fetal membranes was described using two values: 1) size of the prolapsed membrane (P, measured using ultrasound); and 2) size of visible fetal membranes (M, evaluated by speculum examination). The status of cervix was described using two values: 1) dilatation of the narrowest os (O, measured by ultrasound); and 2) functional cervical length (C, measured by ultrasound). The patients were divided into 3 groups as follows: Stage I, patients with visible fetal membranes (M > 0) but with a remaining functional cervix (C > 0) (N = 7); stage II, those with visible fetal membranes (M > 0) and a functional cervical length of 0 but without prolapsed membranes (P = 0) (N = 33); and stage III, those with prolapsed membranes (P > 0) (N = 40).

RESULTS

1) Patients who delivered before 34 weeks of gestation had a significantly lower median gestational age at cerclage operation and a significantly higher median P, M, C values than those who delivered at or beyond 34 weeks of gestation(P < 0.01 for gestational age at operation, P and M values; P < 0.05 for C value); 2) The higher the stage based on PMOC quantification system, the greater the risk of preterm delivery before <24, <32, <34, and <37 weeks of gestation (P < 0.001 for all); 3) The neonatal survival rate was 100 % (7/7) for stage I, 93.9 % (31/33) for stage II, and 60 % (24/40) for stage III.

CONCLUSION

The PMOC system was a simple method to describe the individualized conditions and to predict the risk of preterm births in all spectrums of acute cervical insufficiency.

Do patients with a short cervix, with or without an ultrasound-indicated cerclage, have an increased risk for a small for gestational age newborn?

INTRODUCTION

Mothers with a short cervix have been shown to have increased risk of spontaneous preterm delivery (PTD) and newborn morbidity. Those who require an ultrasound-indicated cerclage experience the highest rates of morbidity. Inflammation has been linked to a short cervix, and it has been linked to pregnancies affected by small for gestational age (SGA) newborns. To date, there are no studies that have investigated an association between a short cervix, with or without an ultrasound-indicated cerclage, and a SGA newborn.

METHODS

This was a case-control study examining all pregnancies with a transvaginal cervical length <25 mm found at their second trimester anatomy scan. Cases were subdivided into those who received an ultrasound-indicated cerclage (Group 1, n = 52) and those who did not (Group 2, n = 139). Controls were defined as pregnancies with a transvaginal cervical length >25 mm with no cerclage (Group 3, n = 186) whose due date was within 2 months of the case pregnancy. Each short cervix case was matched with a control from group 3 in a 1:1 ratio. The primary outcome was birthweight <10% (SGA). Unadjusted data was analyzed with simple odds ratios. A logistic regression was used to control for confounding variables and provide an adjusted odds ratios (aOR).

RESULTS

The incidence of SGA among cases overall (group 1 + group 2) was 13.6% (26/191). In group 3, the SGA incidence was 4.3% (8/186). The adjusted odds ratio (aOR) for a SGA infant was significant, 2.8 (95% CI 1.2, 6.6). Subgroup analysis showed that Group 1 had an increased risk for an SGA infant [aOR 4.9 (95% CI 1.8, 13.7)], but Group 2 did not show a significant finding [aOR 2.3 (95% CI 0.9, 5.7)].

CONCLUSION

Pregnancies complicated by a short cervical length <25mm, with or without a cerclage, were associated with an increased risk for a SGA newborn. Most of this significance was due to the pregnancies which received an ultrasound-indicated cerclage for a mid-trimester short cervix.

Is the Arabin Pessary really useful in preventing preterm birth? A review of literature

The aim of this review is to describe the state of the art in the use of Arabin Pessary for the prevention of spontaneous preterm birth (SPTB). We conducted a review of the literature in order to collect relevant studies concerning the efficacy of Arabin Pessary in preventing preterm birth, also considering it in addition or in comparison with other methods such as cervical cerclage or vaginal progesterone and in both singleton and twin pregnancy. Despite the large number of studies available there is not a clear consensus about the superiority of one of this methods over the others. In addition to this, although Arabin Pessary is widely used in clinical practice, no guidelines for management and use of cervical pessary during pregnancy have been assessed.

Cervical pessary plus vaginal progesterone versus long-term tocolysis for the prevention of preterm birth: An observational retrospective study

OBJECTIVE

To compare cervical pessaries plus vaginal progesterone versus long-term tocolysis for preventing preterm birth for women with a short cervix.

METHODS

Retrospective evaluation of women with singleton pregnancy who received cervical pessaries plus vaginal progesterone (combined group) or ritodrine hydrochloride (tocolysis group) for short cervix (≤25 mm at 20-24 weeks, or ≤20 mm at 25-34 weeks) at a general hospital in Kagoshima, Japan, 2015-2019. The primary outcome was rate of preterm birth (<36 weeks); secondary outcomes were maternal hospital admittance and treatment complications.

RESULTS

Data were evaluated from 95 women (combined group, n=43; tocolysis group, n=52). There was no significant difference in cervical length or gestational age at intervention between the groups. Overall, 3/43 (7.0%) women delivered before 36 weeks in the combined group versus 16/52 (30.8%) in the tocolysis group (relative risk, 0.56; 95% confidence interval, 0.41-0.76; P=0.004). Median maternal admittance was shorter in the combined group (6.6 vs 41.0 days, P<0.001). Although 36/43 (83.7%) women in the combined group reported increased vaginal discharge, no major complications occurred.

CONCLUSION

A combination of pessaries and vaginal progesterone reduced the rate of preterm birth (<36 weeks) for women with short cervix as compared with long-term tocolysis.

Neutrophil elastase in cervical fluid in women with short cervical length

OBJECTIVE

The aim of the study was to determine the relationships between short cervical length (CL) and levels of cervical fluid neutrophil elastase (NE), secretory leukocyte protease inhibitor (SLPI), and interleukin 8 (IL-8) in the second trimester of pregnancy of women who underwent ultrasound-indicated cervical cerclage.

MATERIALS AND METHODS

CL of <25 mm or cervical funneling were included in the short CL group (n = 26) and the normal CL group (n = 22) included women who had CL of ≥25 mm and had no cervical funneling in women between 17 + 0 and 24 + 6 weeks of gestation. Levels of NE, SLPI, and IL-8 were measured by using enzyme-linked immunosorbent assay kits. Mann-Whitney U tests and Spearman's correlation analysis were used for statistical analyses.

RESULTS

Compared with the normal CL group, the short CL group had significantly higher median NE levels (P < 0.001) and higher, though not significant, median IL-8 levels by approximately three times (2107.0 vs. 798.3 pg/mL, P = 0.132). The median SLPI levels in cervical fluid was similar between the two groups (107.6 vs. 103.2 ng/mL, P = 0.499). Short CL had a significant correlations with cervical fluid NE levels (r = -0.475, P = 0.001).

CONCLUSION

Increased cervical fluid NE associated with cervical shortening in second trimester of pregnancy, whereas cervical fluid SLPI had constant levels.

Development of a nomogram for individual preterm birth risk evaluation

OBJECTIVE

This study aimed to develop a new tool for personalised preterm birth risk evaluation in high-risk population.

STUDY DESIGN

813 high-risk asymptomatic pregnant women included in a French multicentric prospective study were analysed. Clinical and paraclinical variables, including screening for bacterial vaginosis with molecular biology, cervical length, have been used to create the nomogram, based on the logistic regression model. The validity was checked by bootstrap. A downloadable calculator was build.

RESULTS

Nine risk factors were included in this model: history of late miscarriage and/or preterm delivery, active smoking, ultrasound cervical length, term of pregnancy at screening, bacterial vaginosis, premature rupture of membranes, daily travel more than 30min. Discrimination and calibration of the nomogram revealed good predictive abilities. The area under the receiver operating characteristic curve was 0.77 (95% CI; 0.72-0.81). The mean absolute error was 0.018, which showed proper calibration. The optimal risk threshold was 23.2% with a sensitivity of 74%, a specificity of 72.7% and a predictive negative value of 90.6%.

CONCLUSION

The nomogram can help to better define individual preterm birth risk in high-risk pregnancies.

Emergency cerclage in twins during mid gestation may have favorable outcomes: Results of a retrospective cohort

PURPOSE

Cervical cerclage treatment for cervical changes at mid trimester is a very controversial topic in twins. The aim of the study was to present our maternal and fetal outcomes of mid-trimester cervical cerclage in twin pregnancies.

BASIC PROCEDURES

This study was performed using data extracted from the medical files of the twin pregnancies whom performed emergency cervical cerclage between January 2012 and March 2018 at Trakya University, Facuty of Medicine, Department of Perinatology.

MAIN FINDINGS

Mean (min.-max.) gestational age at delivery was [27.3 (21-34) weeks]. The median time between cervical cerclage and delivery was 6.4 weeks, while the maximum prolongation of the pregnancy was 11 weeks. The median prolongation period of pregnancy was 4.1 weeks in patients with bulging membranes, but 10 weeks in patients with cervical effacement and cervical shortening. Eight infants died at the neonatal period. Two patients (20%) developed late abortions at 21 and 22 weeks of gestation, and 2 women (20%) delivered extremely premature neonates at the 24th weeks. Overall neonatal mortality rate was 40% (8/20 neonates). Twelve out of twenty were born alive (60%).

PRINCIPAL CONCLUSIONS

Despite the lack of randomized controlled trials, it seems reasonable to offer emergency cervical cerclage to twin pregnancies with cervical shortening (<15mm). For the twin pregnancies with advanced cervical dilatation and protruding membranes, emergency cervical cerclage should be an option only for carefully selected patients after informing about the complications and low success rate.

Cervical alterations in pregnancy

Spontaneous preterm birth (SPTB), defined as delivery before 37 weeks' gestation, remains a significant obstetric dilemma even after decades of research in this field. Although trends from 2007 to 2014 showed the rate of preterm birth slightly decreased, the CDC recently reported the rate of preterm birth has increased for two consecutive years since 2014. Currently, 1 in 10 pregnancies in the US still end prematurely. In this chapter, we focus on the "compartment" of the cervix. The goal is to outline the current knowledge of normal cervical structure and function in pregnancy and the current knowledge of how the cervix malfunctions lead to SPTB. We review the mechanisms by which our current interventions are hypothesized to work. Finally, we outline gaps in knowledge and future research directions that may lead to novel and effective interventions to prevent premature cervical failure and SPTB.

Don't be short-sighted: cervical incompetence in a pregnant patient with acute appendicitis

Delay in diagnosis of cervical incompetence can be detrimental to the fetus. Up to 20-25% of miscarriages in the second trimester can be attributed to the incompetent cervix. Given the profound impact of cervical incompetence on obstetric outcomes, careful attention should be given to evaluation of the cervix on MRI studies in pregnant patients. We present a case of incompetent cervix diagnosed incidentally at the time of MRI performed to evaluate for acute appendicitis.

Pregnancy Outcomes of Women Admitted to a Tertiary Care Centre with Short Cervix

OBJECTIVE

Our aim was to characterize the management and outcome of women admitted to a tertiary high-risk obstetrics unit with a short cervix (≤25 mm), measured on transvaginal ultrasound (TVS), and to determine the latency period from diagnosis to delivery.

METHODS

A retrospective chart review of women admitted to the High Risk Obstetrics Unit at Sunnybrook Health Sciences Centre between 2005-2011 with an ultrasound-identified short cervix was done.

RESULTS

A total of 110 women admitted for a short cervix between 2005-2011 (N = 56 singletons; N = 54 twin gestations) met the inclusion criteria. The mean latency to delivery was 62.6 days; mean GA at delivery was 33.9 weeks. Following 7 and 14 days of admission, 5.5% and 11.8% of women had delivered, respectively. Preterm birth occurred in 70% of all women. Cervical length was a significant factor in predicting latency among singletons, whereas the length of stay in hospital for activity restriction was not.

CONCLUSIONS

Although many women with a short cervix delivered preterm, only a small proportion delivered within 2 weeks of admission. Although it is not clear whether inpatient management improves the pregnancy outcome, these findings have implications for both patient care and health resources.

Multiple gestations and preterm birth

Preterm birth is a major concern in modern obstetrics, and an important source of morbidity and mortality in newborns. Among twin pregnancies, especially, preterm birth is highly prevalent, and it accounts for almost 50% of the complications observed in this obstetrical population. In this article, we review the existing literature regarding the prediction and prevention of preterm birth in both symptomatic and asymptomatic twin pregnancies. In asymptomatic twin pregnancies, the best two predictive tests were cervical length (CL) measurement and cervicovaginal fetal fibronectin (fFN) testing. A single measurement of transvaginal CL at 20-24 weeks of gestation <20 mm or <25 mm is a good predictor of spontaneous preterm birth at <28, <32, and <34 weeks of gestation. A CL beyond 25 mm is associated with a 2% risk for birth before 28 weeks and with a 65% chance for a term pregnancy. Cervicovaginal fFN may be slightly less accurate than CL; however, it has a high negative predictive value in women presenting with threatened preterm labor, as <2% of these women will deliver within one week if the fFN is negative. In symptomatic twin pregnancies, no tests have proven accurate in predicting the risk of preterm birth. For the prevention of preterm birth in asymptomatic twins, regardless of CL, no treatment including bed rest, limitation of home activities, prophylactic tocolysis, progesterone, or cerclage has been shown to reduce the rate of preterm birth. Cervical pessaries might be of interest in cases where there is a short cervix (<25 mm and <38 mm, respectively) but these results need to confirmed in future trials.

[Progesterone and prevention of preterm birth]

The literature confirms the interest of progesterone for prevention of preterm delivery in specific indications for patients carrying a singleton pregnancy. In contrast, randomized trials have shown no benefit using progesterone in the prevention of prematurity in twins and even an adverse effect.

A case report

Preterm birth is one of the causes of perinatal morbidity and mortality. The traditional treatment for a short cervix has been the cerclage in addition with the progesterone administration. Recently, the idea of using vaginal pessaries as a new less invasive method of treatment for the same indication is under discussion. The case of a 29-year-old pregnant woman with an extremely short cervix and the treatment, she underwent during her second pregnancy, is presented. In order to avoid a preterm delivery the patient was treated with the use of a vaginal pessary. After the placement of the pessary and its removal after 37 weeks of gestation, a full term delivery was performed. The pessary was symptom free throughout. In conclusion, the cervical pessary may offer a safe and easy alternative to cerclage for the treatment of cervical insufficiency and prevention of preterm birth.

Progesterone to prevent spontaneous preterm birth

Preterm birth is the leading cause of perinatal morbidity and mortality worldwide, and its prevention is an important healthcare priority. Preterm parturition is one of the 'great obstetrical syndromes' and is caused by multiple etiologies. One of the mechanisms of disease is the untimely decline in progesterone action, which can present as a clinically silent sonographic short cervix in the midtrimester. The detection of a short cervix in the midtrimester is a powerful risk factor for preterm delivery. Vaginal progesterone can reduce the rate of preterm delivery by 45% and the rate of neonatal morbidity (admission to the neonatal intensive care unit, respiratory distress syndrome, need for mechanical ventilation, etc.). To prevent one case of spontaneous preterm birth <33 weeks of gestation, 11 patients with a short cervix would need to be treated (based on an individual patient meta-analysis). Vaginal progesterone reduces the rate of spontaneous preterm birth in women with a short cervix, both with and without a prior history of preterm birth. In patients with a prior history of preterm birth, vaginal progesterone is as effective as cervical cerclage to prevent preterm delivery. 17α-Hydroxyprogesterone caproate has not been shown to be effective in reducing the rate of spontaneous preterm birth in women with a short cervix.

[What use of progesterone to prevent preterm birth?]

Widely prescribed in the years 1970-1980 to prolong gestation, progesterone has regained interest after the publication of randomized trials since 10 years. In women at increased risk of preterm birth with a history of preterm delivery or late miscarriage, the use of progesterone, especially intramuscularly may reduce the incidence of spontaneous preterm birth. In contrast, in cases of preterm labor or twin pregnancies, progesterone efficacy to reduce preterm birth has not been demonstrated. In women with asymptomatic midtrimester sonographic short cervix, randomized studies show conflicting results and new studies are necessary before its widespread utilisation.