Systematic review: Cervical stitch (cerclage) for preventing pregnancy loss: individual patient data meta-analysis

Randomized controlled trials: not always the "gold standard" for evidence in obstetrics and gynecology

Randomized controlled trials are considered the "gold standard" for therapeutic interventions, and it is not uncommon for sweeping changes in medical practice to follow positive results from such trials. However, randomized controlled trials are not without their limitations. Physicians frequently view randomized controlled trials as infallible, whereas they tend to dismiss evidence derived from sources other than randomized controlled trials as less credible or reliable. In several situations in obstetrics and gynecology, there are no randomized controlled trials to help guide the clinician. In these circumstances, it is important to evaluate the entire body of evidence including observational studies, rather than dismiss interventions altogether simply because no randomized controlled trials exist. Randomized controlled trials and observational studies should be viewed as complementary rather than at odds with each other. Some reversals in widely adopted clinical practice have recently been implemented following subsequent studies that contradicted the outcomes of major randomized controlled trials. The most notable of these was the withdrawal from the market of 17-hydroxyprogesterone caproate for preterm birth prevention. Such reversals could potentially have been averted if the inherent limitations of randomized controlled trials were carefully considered before implementing these universal practice changes. This Clinical Opinion underscores the limitations of an exclusive reliance on randomized controlled trials while disregarding other evidence in determining how best to care for patients. Solutions are proposed that advocate that clinicians adopt a more balanced perspective that considers the entirety of the available medical evidence and the individual patient characteristics, needs, and wishes.

Efficacy of ultrasound-indicated cerclage in twin pregnancies: a retrospective case-control study matched by cervical length

BACKGROUND

Twin pregnancies with a progressively shortening cervix in the midterm pregnancy have an increasing risk for spontaneous preterm birth. Currently, there is no known effective method to prevent preterm birth among those women, and the use of an ultrasound-indicated cerclage in twin pregnancies is still controversial.

OBJECTIVE

This study aimed to estimate whether a combination of ultrasound-indicated cerclage, indomethacin, and antibiotics in twin pregnancies between 18 and 26 weeks' gestation could extend the pregnancy, reduce the risk for spontaneous preterm birth, and improve perinatal and neonatal outcomes.

STUDY DESIGN

A retrospective cohort study was conducted. The ultrasound-indicated cerclage group included twin pregnancies with a transvaginal cervical length <25 mm that underwent cerclage at 18 to 26 weeks of gestation in the Women's Hospital, Zhejiang University School of Medicine, from December 2015 through August 2021. Twin pregnancies in our study that underwent cerclage also received antibiotics and indomethacin. A control group of twin pregnancies that were managed expectantly were matched with the treatment group in terms of transvaginal cervical length at diagnosis (±3 mm), gestational age at presentation of diagnosis (±3 weeks), and maternal age (±5 years). An additional subanalysis was performed in which the patients were divided into 2 subgroups based on transvaginal cervical length of either <15 mm or between 15 and 24 mm. The primary outcome was gestational age at delivery. The secondary outcomes were pregnancy latency, the rate of spontaneous preterm birth at <28, <32, <34, <36 weeks' gestation, and neonatal outcomes.

RESULTS

A total of 90 twin pregnancies with a transvaginal cervical length <25 mm were managed with either a cerclage (ultrasound-indicated cerclage group, n=45) or expectantly (control group, n=45). Demographic characteristics were not significantly different between the groups. When compared with the control group, the gestational age at delivery was significantly higher (33.11±3.16 vs 30.22±4.12 weeks; P=.001) and the pregnancy latency was significantly longer (72.40±22.51 vs 45.56±28.82 days; P<.001) in the ultrasound-indicated cerclage group. The rates of spontaneous preterm birth at <28, <32, <34, and <36 weeks' gestation were significantly lower in the ultrasound-indicated cerclage group than in the control group. In terms of neonatal outcomes, there were significant reductions in the overall perinatal mortality (4.4% vs 20.0%; P<.001), neonatal intensive care unit admissions (69.0% vs 92.6%; P<.001), and composite adverse neonatal outcomes (43.7% vs 64.7%; P=.010) for the ultrasound-indicated cerclage group when compared with the control group. In the subgroup of women with a transvaginal cervical length of between 15 and 24 mm (with 21 in the ultrasound-indicated cerclage group vs 21 controls), the data were adjusted for maternal age, pregestational body mass index, in vitro fertilization, operative hysteroscopy, previous cervical surgery, previous spontaneous preterm birth, white blood cell counts, C-reactive protein level, neutrophil to lymphocyte ratio, and the shortest transvaginal cervical length measured at diagnosis. In ultrasound-indicated cerclage group, gestational age at delivery was significantly higher (32.95±3.81 vs 30.24±4.01 weeks; beta, 3.34; 95% confidence interval, 0.14-6.55; P=.042), pregnancy latency was significantly prolonged (77.19±24.81 vs 48.52±29.67 days; beta, 33.81; 95% confidence interval, 12.29-55.34; P=.003), and the rates of spontaneous preterm birth <36 weeks' gestation (57.1% vs 95.2%; adjusted odds ratio, 0.03; 95% confidence interval, 0.01-0.69; P=.029) was significantly decreased, and for neonatal outcomes, there were significant reductions in neonatal intensive care unit admissions (53.7% vs 96.7%; adjusted odds ratio, 0.04; 95% confidence interval, 0.01-0.32; P=.003) and the composite adverse neonatal outcomes (39.0% vs 73.3%; adjusted odds ratio, 0.24; 95% confidence interval, 0.08-0.68; P=.008) in the ultrasound-indicated cerclage group when compared with the control group. In the subgroup of women with a transvaginal cervical length <15 mm, gestational age at delivery was higher (33.25±2.52 vs 30.00±4.33 weeks; beta, 3.96; 95% confidence interval, 1.51-6.42; P=.002), pregnancy latency was significantly prolonged (68.21±19.85 vs 42.96±28.43 days; beta, 30.11; 95% confidence interval, 12.42-47.81; P=.001), rates of spontaneous preterm birth at <32 weeks (16.7% vs 54.2%; adjusted odds ratio, 0.10; 95% confidence interval, 0.01-0.61; P=.020) and <34 weeks (54.2% vs 83.3%, adjusted odds ratio, 0.08; 95% confidence interval, 0.01-0.66; P=.019) of gestation was significantly decreased, and neonatal birthweight was significantly increased (2023.96±510.35 vs 1421.77±611.40 g; beta, 702.40; 95% confidence interval, 297.02-1107.78; P=.001) in the ultrasound-indicated cerclage group when compared with the control group.

CONCLUSION

Cerclage among women with twin pregnancies with a transvaginal cervical length <25 mm may reduce the rate of spontaneous preterm birth and improve perinatal and neonatal outcomes when compared with expectant management. It is worth noting that even with a short transvaginal cervical length of 15 to 24 mm, cerclage will significantly decrease the risk of delivery at <36 weeks' gestation and prolong pregnancy latency. Among women with a short transvaginal cervical length <15 mm, cerclage will significantly decrease the risk of delivery at <32 and <34 weeks' gestation and prolong pregnancy latency.

Comparison of emergency cervical cerclage and expectant treatment in cervical insufficiency in singleton pregnancy: A meta-analysis

OBJECTIVE

To compare the therapeutic effects of emergency cervical cerclage and expectant treatment in preterm birth due to cervical insufficiency in singleton pregnancy.

METHODS

A combination of subject words and free words was used to search major domestic and foreign databases. According to inclusion and exclusion criteria, 23 studies were included that met the criteria and quality evaluation and data extraction was carried out. The data were analyzed using STATA 15 and the reporting was done in reference to the list of Preferred Reporting Items for Systematic and Meta-Analyses.

RESULTS

Emergency cervical cerclage was superior to expectant treatment for the primary outcome of pregnancy prolongation (WMD = 5.752, 95% CI 5.194-6.311, 22 studies, N = 1435, I2 = 97.1%, P = 0.000). Cervical cerclage was also superior to expectant treatment for the secondary outcomes of neonatal birth weight (WMD = 1051.542, 95% CI 594.107-1508.977, 9 studies, N = 609, I2 = 96.4%, P = 0.000), neonatal Apgar 1' (WMD = 2.8720, 95% CI: 2.105-3.639, 11 studies, N = 716, I2 = 99.0%, P = 0.000), number of live births (OR = 6.018, 95% CI 2.882-12.568, 10 studies, N = 724, I2 = 55.3%, P = 0.000), deliveries after 32 weeks (OR = 8.030, 95% CI 1.38-46.892, 8 studies, N = 381, I2 = 85.9%, P = 0.021). deliveries after 34 weeks (OR = 15.91, 95% CI 5.92-42.77, 9 studies, N = 560, I2 = 59.6%, P = 0.000), number of vaginal deliveries (OR = 3.24, 95% CI 1.32-7.90, 8 studies, N = 502, I2 = 69.4%, P = 0.018), and number of neonatal survivals (OR = 9.300, 95% CI 3.472-24.910, 10 studies, N = 654, I2 = 80.5%, P = 0.000). No difference between emergency cervical cerclage and expectant treatment was found in patients with chorioamnionitis (OR = 1.85, 95% CI 0.602-4.583, 4 studies, N = 296, I2 = 16.3%, P = 0.273).

CONCLUSION

Before the 28th week of pregnancy, emergency cervical cerclage can significantly prolong the gestational week and improve the neonatal survival rate, compared to expectant treatment, in women with singleton pregnancies who have a dilated uterine orifice caused by cervical insufficiency.

McDonald versus Shirodkar cervical cerclage for prevention of preterm birth: a systematic review and meta-analysis of pregnancy outcomes

OBJECTIVE

To compare pregnancy outcomes of patients undergoing either McDonald or Shirodkar cervical cerclage.

METHODS

PubMed, Web of Science, Scopus, and Google scholar were systematically searched up to June 2020. Inter-study heterogeneity was assessed using Cochrane's Q test and the I² statistic. Data were pooled using the fixed- or random-effects model and expressed as relative risk (RR) or weighted mean difference (WMD) as appropriately.

RESULTS

A total of eight observational studies, reporting data on 724 pregnancies, were included in this meta-analysis. As compared to the Shirodkar cerclage, the pooled findings showed that the gestational age at delivery (WMD = -1.95, 95% CI: -2.89 to -1.01, p < .001; I² = 57.5%) and birth weight (WMD = -355.69, 95% CI: -413.76 to -297.62, p < .001; I² = 28.8%) were significantly lower in McDonald cerclage. The risk of preterm premature rupture of the membranes (PPROM) (RR = 1.76; 95% CI: 1.14 - 2.71; I² = 0.0%) and neonatal intensive care unit (NICU) admission (RR = 1.61; 95% CI: 1.09 - 2.39; I² = 62.1%) were also higher for McDonald group. However, no significant difference was observed between both groups in terms of cesarean delivery and perinatal/neonatal death.

CONCLUSION

McDonald cerclage is associated with a shorter duration of pregnancy, lower mean birth weight and increased risk of PPROM and NICU admission compared to the Shirodkar procedure.

Laparoscopic emergency cervicoisthmic cerclage in second trimester of pregnancy: A case series report

PURPOSE

The aim of this study was to evaluate the feasibility and safety of Laparoscopic emergency cervicoisthmic cerclage in second trimester of pregnancy.

METHODS

Between November 2015 and March 2019 5 patients underwent Laparoscopic emergency cervicoisthmic cerclage. All women had showed cervical insufficiency with dilation in the second trimester due to extensive conisation (3 patients) or re-conisation (2 patients) and failed transvaginal cerclage (5 patients) due to a short vaginal cervix. Patients' characteristics were obtained from hospital's medical record and we evaluated surgical data, intra, postoperative complications, and perinatal outcome. All operations were performed by the same surgeon.

RESULTS

The average operation time was 88 min (ranging from 80 to 95 minutes), the average estimated blood loss during the procedure was less than 100 mL and there were no perioperative or postoperative complications. The mean gestational age at surgery was 14.4 (ranging from 14.2 to 16) weeks. All women underwent an elective CS after 38 weeks of gestation. The overall pregnancy survival rate was 100 %, the mean gestational age at delivery was 38.1 weeks (ranging from 38.0 to 38.5 weeks) and the mean birth weight was 3190 g (g) (ranging from 2980 g to 3350 g).

CONCLUSION

Laparoscopic cervicoisthmic cerclage might be an alternative approach even in the early second trimester of pregnancy. Our study's success rates compare favourably to the laparotomy approach and the laparoscopic cervicoisthmic cerclage showed a relatively high success rate in women who are at risk of poor obstetric outcomes. Of course, the surgeon's experience and competence plays a key role and this approach should only be attempted in well-organized units.

How often can meta-analyses of individual-level data individualize treatment? A meta-epidemiologic study

BACKGROUND

One of the claimed main advantages of individual participant data meta-analysis (IPDMA) is that it allows assessment of subgroup effects based on individual-level participant characteristics, and eventually stratified medicine. In this study, we evaluated the conduct and results of subgroup analyses in IPDMA.

METHODS

We searched PubMed, EMBASE and the Cochrane Library from inception to 31 December 2014. We included papers if they described an IPDMA based on randomized clinical trials that investigated a therapeutic intervention on human subjects and in which the meta-analysis was preceded by a systematic literature search. We extracted data items related to subgroup analysis and subgroup differences (subgroup-treatment interaction p < 0.05).

RESULTS

Overall, 327 IPDMAs were eligible. A statistically significant subgroup-treatment interaction for the primary outcome was reported in 102 (36.6%) of 279 IPDMAs that reported at least one subgroup analysis. This corresponded to 187 different statistically significant subgroup-treatment interactions: 124 for an individual-level subgrouping variable (in 76 IPDMAs) and 63 for a group-level subgrouping variable (in 36 IPDMAs). Of the 187, only 7 (3.7%; 6 individual and 1 group-level subgrouping variables) had a large difference between strata (standardized effect difference d  ≥  0.8). Among the 124 individual-level statistically significant subgroup differences, the IPDMA authors claimed that 42 (in 21 IPDMAs) should lead to treating the subgroups differently. None of these 42 had d  ≥  0.8.

CONCLUSIONS

Availability of individual-level data provides statistically significant interactions for relative treatment effects in about a third of IPDMAs. A modest number of these interactions may offer opportunities for stratified medicine decisions.

The use of specialised preterm birth clinics for women at high risk of spontaneous preterm birth: a systematic review

Background

Specialised preterm birth clinics care for women at high risk of spontaneous preterm birth. This systematic review assesses current practice within preterm birth clinics globally.

Methods

A comprehensive search strategy was used to identify all studies on preterm birth clinics on the MEDLINE, Embase, PsycINFO, CENTRAL and CINAHL databases. There were no restrictions to study design. Studies were limited to the English language and publications from 1998 onwards. Two reviewers assessed studies for inclusion, performed data extraction and reviewed methodological quality. Primary outcomes were referral criteria, investigations and interventions offered in preterm birth clinics. Secondary outcomes were the timing of planned first and last appointments and frequency of review.

Results

Thirty-two records fulfilled eligibility criteria and 20 studies were included in the main analysis following grouping of records describing the same study or clinic. Studies were of mixed study design and methodological quality. A total of 39 clinics were described; outcome data was not available for all clinics. Referral criteria included previous spontaneous preterm birth (38/38, 100%), previous mid-trimester loss (34/38, 89%) and previous cervical surgery (33/38, 87%). All clinics offered transvaginal cervical length scans. Additional investigations varied, including urogenital swabs (16/28, 57%) and fetal fibronectin (8/28, 29%). The primary treatment of choice for a sonographic short cervix was cervical cerclage in 10/33 (30%) clinics and vaginal progesterone in 6/33 (18%), with 10/33 (30%) using multiple first-line options and 6/33 (18%) using a combination of treatments. The majority of clinics planned timing of first review for 12–16 weeks (30/35, 86%) and the frequency of review was usually determined by clinical findings (18/24, 75%). There was a wide variation in gestational age at clinic discharge between 24 and 37 weeks.

Conclusions

There is variation in the referral criteria, investigations and interventions offered in preterm birth clinics and in the timing and frequency of review. Consistency in practice may improve with the introduction of consensus guidelines and national preterm birth prevention programmes.

Trial registration

Systematic review registration number: CRD42019131470.

The efficacy of cervical cerclage combined with a pessary for the prevention of spontaneous preterm birth

AIMS

This study compared the effectiveness and safety of cervical cerclage combined with cervical pessary in the treatment of cervical incompetence and that of cervical cerclage alone and cervical pessary alone.

METHODS

We performed a prospective cohort study of women with cervical incontinence. Subjects were randomized into three groups: cerclage, pessary, and cerclage and pessary combined.

RESULTS

A total of 75 patients with cervical incompetence were enrolled: 37.3% patients had a cervical length <15 mm, and 62.5% had a cervical length of 15-25 mm. Patients with increased body mass index were significantly likely to have a short cervix (p = .06); patients with a short cervix had earlier rupture of the membrane. The cerclage and pessary groups had more spontaneous abortions than the combined treatment group, which had no abortions or premature births. The mean gestational ages at delivery for the cerclage group (37.82 weeks) and the pessary group (35.73 weeks) were smaller than for the combined treatment group (38.33 weeks). The premature rupture of membranes that was correlated with cervical length had a higher incidence in the pessary group (26.9%).

CONCLUSION

Placement of a cervical cerclage combined with a cervical pessary is a safe technique and has a high success rate in the treatment of cervical incompetence.

Cerclage for women with twin pregnancies: a systematic review and metaanalysis

OBJECTIVE DATA

This study was conducted to estimate whether cerclage could extend the prolongation of pregnancy, reduce the risk of preterm birth, and improve perinatal outcomes in women with twin pregnancies.

STUDY ELIGIBILITY CRITERIA

We included randomized controlled trials and cohort studies comparing the efficacy of cerclage with no cerclage for women with twin pregnancies.

STUDY APPRAISAL AND SYNTHESIS METHODS

The following databases were searched for all published studies that compared cerclage placement with expectant management in twin pregnancies from inception to July 2018: Medline, EMBASE, Scopus, ClinicalTrials.gov, Web of Science, and Cochrane Library. Each report was reviewed for inclusion or exclusion standard, and data extraction was performed by 2 authors independently.

RESULTS

A total of 16 studies with 1211 women that met the inclusion criteria were included in the final analysis. Our outcomes indicated that cerclage placement for twin pregnancies with a cervical length of <15 mm was associated with significant prolongation of pregnancy by a mean difference of 3.89 weeks of gestation (95% confidence interval, 2.19-5.59; P=.000; I²=0%) and a reduction of preterm birth at <37 weeks of gestation (risk ratio, 0.86; 95% confidence interval, 0.74-0.99; P=.040; I²=0%), <34 weeks of gestation (risk ratio, 0.57; 95% confidence interval, 0.43-0.75; P=.000; I²=0%) and <32 weeks of gestation (risk ratio, 0.61; 95% confidence interval, 0.41-0.90; P=.010; I²=0%), compared with those pregnancies in the control group. For women with a dilated cervix of >10 mm, cerclage placement was associated with significant prolongation of pregnancy by a mean difference of 6.78 weeks of gestation (95% confidence interval, 5.32-8.24; P=.000; I²=0%); a reduction of preterm birth at <34 weeks of gestation (risk ratio, 0.56; 95% confidence interval, 0.45-0.69; P=.000; I²=28%), <32 weeks of gestation (risk ratio, 0.50; 95% confidence interval, 0.38-0.65; P=.000; I²=14%), <28 weeks of gestation (risk ratio, 0.41; 95% confidence interval, 0.20-0.85; P=.030; I²=80%), and <24 weeks of gestation (risk ratio, 0.35; 95% confidence interval, 0.18-0.67; P=.001; I²=24%), and improvement of perinatal outcomes compared with those in the control group. However, for twin pregnancies with a normal cervical length (eg, cerclage for an indication for women with a history of preterm birth or twin alone), the efficacy of cerclage placement was less certain because of the limited data.

CONCLUSION

Our metaanalysis indicates that cerclage placement is beneficial for the reduction of preterm birth and the prolongation of pregnancy in twin pregnancies with a cervical length of <15 mm or dilated cervix of >10 mm. However, the benefit of history-indicated or twin alone-indicated cerclage is less certain in twin pregnancies with normal cervical length according to current literature. Further high-quality studies were needed to confirm the findings.

[Epidemiology, risk factors and child prognosis: CNGOF Preterm Premature Rupture of Membranes Guidelines]

OBJECTIVES

To synthetize the available evidence regarding the incidence and risk factors of preterm premature rupture of membranes (PPROM). To describe the evolution of pregnancy, neonatal outcomes and the prognosis of infants born in a context of PPROM, according to the existence of an associated intrauterine infection and to the latency duration.

METHOD

Consultation of the Medline database, from 1980 to February 2018.

RESULTS

PPROM before 37 and before 34 weeks' gestation occur in 2-3% and <1% of pregnancies, respectively (LE2). Although many risk factors are identified, few are modifiable, and the vast majority of patients have no risk factors (LE2). Consequently, individual prediction of the risk of PPROM and primary prevention measures have not been shown to be effective and are not recommended in clinical practice (Grade B). Most women give birth within the week following PPROM (LE2). The main complications of PPROM are prematurity, intrauterine infection and obstetric and maternal complications (LE2). Latency duration and the frequency of complications decrease with increasing gestational age at PPROM (LE2). Neonatal prognosis is largely conditioned by gestational age at birth, with no apparent over-risk of poor outcomes linked to PPROM compared to other causes of preterm birth (LE2). In contrast, intrauterine infection is associated with an increased risk of in utero fetal death (LE3), necrotizing enterocolitis (LE1) and early-onset sepsis (LE2). The association of intrauterine infection with neurological morbidity remains controversial. Prolongation of latency, from gestational age at PPROM, is beneficial for the child (LE2).

CONCLUSION

PPROM is a major cause of prematurity and short- and long-term mortality and morbidity. Antenatal care is an important issue for obstetric and pediatric teams, aiming to reduce complications and adverse consequences for both mother and child.

Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy

BACKGROUND

Cervical cerclage is a well-known surgical procedure carried out during pregnancy. It involves positioning of a suture (stitch) around the neck of the womb (cervix), aiming to give mechanical support to the cervix and thereby reduce risk of preterm birth. The effectiveness and safety of this procedure remains controversial. This is an update of a review last published in 2012.

OBJECTIVES

To assess whether the use of cervical stitch in singleton pregnancy at high risk of pregnancy loss based on woman's history and/or ultrasound finding of 'short cervix' and/or physical exam improves subsequent obstetric care and fetal outcome.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (30 June 2016) and reference lists of identified studies.

SELECTION CRITERIA

We included all randomised trials of cervical suturing in singleton pregnancies. Cervical stitch was carried out when the pregnancy was considered to be of sufficiently high risk due to a woman's history, a finding of short cervix on ultrasound or other indication determined by physical exam. We included any study that compared cerclage with either no treatment or any alternative intervention. We planned to include cluster-randomised studies but not cross-over trials. We excluded quasi-randomised studies. We included studies reported in abstract form only.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion. Two review authors independently assessed risk of bias and extracted data. We resolved discrepancies by discussion. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

This updated review includes a total of 15 trials (3490 women); three trials were added for this update (152 women). Cerclage versus no cerclageOverall, cerclage probably leads to a reduced risk of perinatal death when compared with no cerclage, although the confidence interval (CI) crosses the line of no effect (RR 0.82, 95% CI 0.65 to 1.04; 10 studies, 2927 women; moderate quality evidence). Considering stillbirths and neonatal deaths separately reduced the numbers of events and sample size. Although the relative effect of cerclage is similar, estimates were less reliable with fewer data and assessed as of low quality (stillbirths RR 0.89, 95% CI 0.45 to 1.75; 5 studies, 1803 women; low quality evidence; neonatal deaths before discharge RR 0.85, 95% CI 0.53 to 1.39; 6 studies, 1714 women; low quality evidence). Serious neonatal morbidity was similar with and without cerclage (RR 0.80, 95% CI 0.55 to 1.18; 6 studies, 883 women; low-quality evidence). Pregnant women with and without cerclage were equally likely to have a baby discharged home healthy (RR 1.02, 95% CI 0.97 to 1.06; 4 studies, 657 women; moderate quality evidence).Pregnant women with cerclage were less likely to have preterm births compared to controls before 37, 34 (average RR 0.77, 95% CI 0.66 to 0.89; 9 studies, 2415 women; high quality evidence) and 28 completed weeks of gestation.Five subgroups based on clinical indication provided data for analysis (history-indicated; short cervix based on one-off ultrasound in high risk women; short cervix found by serial scans in high risk women; physical exam-indicated; and short cervix found on scan in low risk or mixed populations). There were too few trials in these clinical subgroups to make meaningful conclusions and no evidence of differential effects. Cerclage versus progesteroneTwo trials (129 women) compared cerclage to prevention with vaginal progesterone in high risk women with short cervix on ultrasound; these trials were too small to detect reliable, clinically important differences for any review outcome. One included trial compared cerclage with intramuscular progesterone (75 women) which lacked power to detect group differences. History indicated cerclage versus ultrasound indicated cerclageEvidence from two trials (344 women) was too limited to establish differences for clinically important outcomes.

AUTHORS' CONCLUSIONS

Cervical cerclage reduces the risk of preterm birth in women at high-risk of preterm birth and probably reduces risk of perinatal deaths. There was no evidence of any differential effect of cerclage based on previous obstetric history or short cervix indications, but data were limited for all clinical groups. The question of whether cerclage is more or less effective than other preventative treatments, particularly vaginal progesterone, remains unanswered.

Does cervical cerclage decrease preterm birth in twin pregnancies with a short cervix?

PURPOSE

To determine if use of cerclage in twin gestations with mid-trimester short cervix is associated with decreased preterm birth rate.

STUDY DESIGN

This is a retrospective cohort of twin gestations identified with cervical length of ≤2.5 cm before 24 weeks of gestation through the perinatal ultrasound database of two institutions from 2008 to 2014. Patients with and without cerclage were compared for a primary outcome of preterm birth at <35 weeks. A pre-planned sub-group analysis of patients with cervical length ≤1.5 cm was also performed.

RESULTS

Eighty-two patients were included; 43 received cerclage, 39 did not. Mean gestational age at cerclage placement was 20.8 weeks. There was no significant difference in rate of preterm birth <35 weeks between the groups (34.9% versus 48.7%, respectively). In the sub-group analysis of patients with cervical length ≤1.5 cm, there was a significant decreased risk of preterm birth <35 weeks [37% versus 71.4%; adjusted RR 0.49 (0.26-0.93)].

CONCLUSION

Cerclage placement for cervical length ≤2.5 cm in twin gestations did not decrease the rate of preterm birth at <35 weeks; however, cerclage placement for cervical length ≤1.5 cm was associated with a significantly decreased rate of preterm birth <35 weeks when compared to patients managed without cerclage.

Insuffisance cervicale et cerclage cervical

OBJECTIF

La présente directive clinique a pour but de fournir un cadre de référence que les cliniciens pourront utiliser pour identifier les femmes qui sont exposées aux plus grands risques de connaître une insuffisance cervicale, ainsi que pour déterminer les circonstances en présence desquelles la mise en place d'un cerclage pourrait s'avérer souhaitable. RéSULTATS: La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans PubMed ou MEDLINE, CINAHL et The Cochrane Library en 2012 au moyen d'un vocabulaire contrôlé (p. ex. « uterine cervical incompetence ») et de mots clés appropriés (p. ex. « cervical insufficiency », « cerclage », « Shirodkar », « cerclage », « MacDonald », « cerclage », « abdominal », « cervical length », « mid-trimester pregnancy loss »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles. Aucune restriction n'a été appliquée en matière de date ou de langue. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'en janvier 2011. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau). RECOMMANDATIONS.

[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.

Cervical stitch (cerclage) for preventing preterm birth in multiple pregnancy

BACKGROUND

Cervical cerclage is a surgical intervention involving placing a stitch around the uterine cervix. The suture material aims to prevent cervical shortening and opening, thereby reducing the risk of preterm birth. The effectiveness and safety of this procedure in multiple gestations remains controversial.

OBJECTIVES

To assess whether the use of a cervical cerclage in multiple gestations, either at high risk of pregnancy loss based on just the multiple gestation (history-indicated cerclage), the ultrasound findings of 'short cervix' (ultrasound-indicated cerclage), or the physical exam changes in the cervix (physical exam-indicated cerclage), improves obstetrical and perinatal outcomes. The primary outcomes assessed were perinatal deaths, serious neonatal morbidity, and perinatal deaths and serious neonatal morbidity.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 June 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised controlled trials (RCTs) of cervical cerclage in multiple pregnancies. Quasi-RCTs and RCTs using a cluster-randomised design were eligible for inclusion (but none were identified). Studies using a cross-over design and those presented only as abstracts were not eligible for inclusion.We included studies comparing cervical cerclage with no cervical cerclage in multiple pregnancies.Studies comparing cervical stitch versus any other preventative therapy (e.g. progesterone) in multiple pregnancies, and studies involving comparisons between different cerclage protocols (history-indicated versus ultrasound-indicated versus physical exam-indicated cerclage) were also eligible for inclusion but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias. Two review authors extracted data. Data were checked for accuracy.

MAIN RESULTS

We included five trials, which in total randomised 1577 women, encompassing both singleton and multiple gestations. After excluding singletons, the final analysis included 128 women, of which 122 women had twin gestations, and six women had triplet gestations. Two trials (n = 73 women) assessed history-indicated cerclage, while three trials (n = 55 women) assessed ultrasound-indicated cerclage. The five trials were judged to be of average to above average quality, with three of the trials at unclear risk regarding selection and detection biases.Concerning the primary outcomes, when outcomes for cerclage were pooled together for all indications and compared with no cerclage, there was no statistically significant differences in perinatal deaths (19.2% versus 9.5%; risk ratio (RR) 1.74, 95% confidence intervals (CI) 0.92 to 3.28, five trials, n = 262), serious neonatal morbidity (15.8% versus 13.6%; average RR 0.96, 95% CI 0.13 to 7.10, three trials, n = 116), or composite perinatal death and neonatal morbidity (40.4% versus 20.3%; average RR 1.54, 95% CI 0.58 to 4.11, three trials, n = 116).Among the secondary outcomes, there were no significant differences between the cerclage and the no cerclage groups. To name a few, there were no significant differences among the following: preterm birth less than 34 weeks (average RR 1.16, 95% CI 0.44 to 3.06, four trials, n = 83), preterm birth less than 35 weeks (average RR 1.11, 95% CI 0.58 to 2.14, four trials, n = 83), low birthweight less than 2500 g (average RR 1.10, 95% CI 0.82 to 1.48, four trials, n = 172), very low birthweight less than 1500 g (average RR 1.42, 95% CI 0.52 to 3.85, four trials, n = 172), and respiratory distress syndrome (average RR 1.70, 95% CI 0.15 to 18.77, three trials, n = 116). There were also no significant differences between the cerclage and no cerclage groups when examining caesarean section (elective and emergency) (RR 1.24, 95% CI 0.65 to 2.35, three trials, n = 77) and maternal side-effects (RR 3.92, 95% CI 0.17 to 88.67, one trial, n = 28).Examining the differences between prespecified subgroups, ultrasound-indicated cerclage was associated with an increased risk of low birthweight (average RR 1.39, 95% CI 1.06 to 1.83, Tau² = 0.01, I² = 15%, three trials, n = 98), very low birthweight (average RR 3.31, 95% CI 1.58 to 6.91, Tau² = 0, I² = 0%, three trials, n = 98), and respiratory distress syndrome (average RR 5.07, 95% CI 1.75 to 14.70, Tau² = 0, I² = 0%, three trials, n = 98). However, given the low number of trials, as well as substantial heterogeneity and subgroup differences, these data must be interpreted cautiously.No trials reported on long-term infant neurodevelopmental outcomes. There were no physical exam-indicated cerclages available for comparison among the studies included.

AUTHORS' CONCLUSIONS

This review is based on limited data from five small studies of average to above average quality. For multiple gestations, there is no evidence that cerclage is an effective intervention for preventing preterm births and reducing perinatal deaths or neonatal morbidity.

The effect of cerclage in twin gestations with short cervix: a Bayesian evaluation

OBJECTIVE

Bayesian inference allows the revision of prior clinical estimates of treatment effectiveness based on current data. We apply it to a published dataset evaluating the effect of cerclage upon preterm delivery in twin gestations with a short cervix.

STUDY DESIGN

Prior probability distributions for delivery <35 weeks gestation for the control group and the treatment (cerclage) group were constructed under assumptions ranging from treatment having no effect (prior A) to halving early deliveries (prior C). Likelihood functions were calculated based on a published meta-analysis. Posterior probability densities were derived from which risk ratios for early delivery were computed, with 95% credible intervals and the probability of cerclage benefit.

RESULTS

Median posterior risk ratios (95% credible intervals) for delivery <35 weeks with cerclage are 1.51 (1.02-2.33) for prior A and 1.11 (0.72-1.77) for prior C. The probability of cerclage benefit ranged from 2.1% for prior A to 31.4% for prior C. By comparison, the conventional risk ratio (95% confidence interval) for early delivery, based on the data alone, is 2.08 (1.18-3.69).

CONCLUSIONS

As might be anticipated, those with low expectation of cerclage benefit remain more convinced of the ineffectiveness (or harm) of the procedure than those with higher expectations.

Cervical length in asymptomatic twin pregnancies: prospective multicenter comparison of predictive indicators

Abstract Objective: To determine whether cervical shortening between 22 and 27 weeks predicts spontaneous preterm delivery before 34 weeks better than a single cervical length (CL) measurement at 22 or 27 weeks in asymptomatic twins.

METHODS

Prospective 13-center study over a 2-year-period. CL was measured in 120 asymptomatic twin pregnancies. The area under the ROC curve was calculated for each parameter and the cutoff point providing the best diagnostic performance, sensitivity and specificity for predicting spontaneous delivery<34 weeks was defined too.

RESULTS

About 13/116 women gave birth before 34 weeks. The three ROC curves differed significantly at the 0.05 level. The best cutoff points were CL≤35 mm at 22 weeks, CL≤25 mm at 27 weeks and cervical shortening≥20%. For equal sensitivity values for each, specificity for CL≤25 mm at 27 weeks was 87.5%, significantly better.

CONCLUSIONS

The performance of cervical shortening for the prediction of preterm delivery of asymptomatic twins before 34 weeks does not differ from that of CL measurements at 22 or 27 weeks. The modest predictive value of CL at 22 weeks and of cervical shortening is an argument against recommending routine CL measurements.

Use of cerclage in triplet pregnancies with an asymptomatic short cervix

OBJECTIVES

The purpose of this study was to compare the outcomes of triplet pregnancies in women with asymptomatic cervical shortening with and without a cervical cerclage.

METHODS

A retrospective review of all triplet pregnancies with biweekly serial cervical length surveillance was performed. Cervical shortening was defined as a cervical length of 2.5 cm or less before 24 weeks' gestation. Patients with cervical shortening managed with cerclage were compared to those managed expectantly. The primary outcome was the gestational age at delivery, with secondary outcomes including birth weight, neonatal intensive care unit length of stay, and composite neonatal outcome. Statistical significance was defined as P < .05.

RESULTS

Sixteen patients underwent cerclage placement versus 8 managed expectantly (control group). The median gestational ages at delivery were similar between the groups (cerclage, 31.3 weeks; interquartile range [IQR], 29.3-32.3 weeks; control, 29.8 weeks; IQR, 27.5-32.4 weeks; P = .71). The median birth weights were also similar between the groups (cerclage, 1283 g; IQR, 800-1626 g; control, 1109 g; IQR, 776-1500 g; P = .54). There was no significant difference in composite neonatal outcomes between the cerclage and control groups (P = .67).

CONCLUSIONS

In this limited case-control study, we found no benefit in terms of pregnancy prolongation or neonatal outcomes with cerclage placement for triplet gestations complicated by an asymptomatic short cervix.

A systematic review of individual patient data meta-analyses on surgical interventions

BACKGROUND

Compared to subgroup analyses in a single study or in a traditional meta-analysis, an individual patient data meta-analysis (IPDMA) offers important potential advantages. We studied how many IPDMAs report on surgical interventions, how many of those surgical IPDMAs perform subgroup analyses, and whether these subgroup analyses have changed decision-making in clinical practice.

METHODS

Surgical IPDMAs were identified using a comprehensive literature search. The last search was conducted on 24 April 2012. For each IPDMA included, we obtained information using a standardized data extraction form, and the quality of reporting was assessed. We also checked whether results were implemented in clinical guidelines.

RESULTS

Of all 583 identified IPDMAs, 22 (4%) reported on a surgical intervention. Eighteen (82%) of these IPDMAs presented subgroup analyses. Subgroups were mainly based on patient and disease characteristics. The median number of reported subgroup analyses was 3.5 (IQR 1.25-6.5). Statistical methods for subgroup analyses were mentioned in 11 (61%) surgical IPDMAs.Eleven (61%) of the 18 IPDMAs performing subgroup analyses reported a significant overall effect estimate, whereas six (33%) reported a non-significant one. Of the IPDMAs that reported non-significant overall results, three IPDMAs (50%) reported significant results in one or more subgroup analyses. Results remained significant in one or more subgroups in eight of the IPDMAs (73%) that reported a significant overall result.Eight (44%) of the 18 significant subgroups appeared to be implemented in clinical guidelines. The quality of reporting among surgical IPDMAs varied from low to high quality.

CONCLUSION

Many of the surgical IPDMAs performed subgroup analyses, but overall treatment effects were more often emphasized than subgroup effects. Although, most surgical IPDMAs included in the present study have only recently been published, about half of the significant subgroups were already implemented in treatment guidelines.

Perinatal death of triplet pregnancies by chorionicity

OBJECTIVE

The purpose of this study was to evaluate the perinatal risk of death by chorionicity at >22 weeks of gestation of triplet pregnancies.

STUDY DESIGN

In a retrospective cohort study, the perinatal data were collected from triplet pregnancies in Japanese perinatal care centers between 1999 and 2009. We included maternal characteristics and examined the following factors: prenatal interventions, pregnancy outcome, and neonatal outcome. The association between fetal or neonatal death of triplets and chorionicity was evaluated by logistic regression analysis.

RESULTS

After the exclusion of 253 cases, the study group comprised 701 cases: 507 trichorionic triamniotic (TT) triplet pregnancies, 144 diamniotic triamniotic (DT) triplet pregnancies, and 50 monochorionic triamniotic (MT) triplet pregnancies. The mortality rate (fetal death at >22 weeks of gestation; neonatal death) in triplets was 2.6% and included 2.1% of TT triplet pregnancies, 3.2% of DT triplet pregnancies, and 5.3% of MT triplet pregnancies. No significant risk of death was identified in DT triplet pregnancies; however, MT triplet pregnancies had a 2.6-fold greater risk (adjusted odds ratio, 2.60; 95% confidence interval, 1.17-5.76; P = .019) compared with TT triplet pregnancies. Prophylactic cervical cerclage did not reduce the perinatal mortality rate at >22 weeks of gestation in triplets.

CONCLUSION

The risk of death for MT triplet pregnancies is significantly higher than that of TT triplet pregnancies; however, the risk of death for DT triplet pregnancies is not.

Multifetal pregnancies: preterm admissions and outcomes

OBJECTIVE

To describe the rates of antenatal hospital admission during twin or higher order multifetal pregnancies, and the admission outcomes as discharge undelivered, transfer to higher care, or spontaneous or elective delivery.

METHODS

Cohort study using linked birth and hospital data. The cohort comprised women who gave birth to twins or higher order multiple infants of≥24 weeks gestation in 2001-2008 and who were admitted to hospital in weeks 20-36 of the pregnancy.

RESULTS

In 63.4% of 10 779 twin pregnancies and 99.5% of 197 triplet and quadruplet pregnancies, the woman was admitted to hospital at least once in weeks 20-36 of the pregnancy, for a total 10 985 admissions. Almost half the admissions (46.3%) ended in discharge without delivery, 10.7% in transfer to higher care, 21.1% in spontaneous labour and birth, and 21.8% in elective delivery (induction or prelabour Caesarean section). The reason for admission was preterm labour in 34.2% of admissions.

CONCLUSIONS

Hospital admission during pregnancy is common for women with multifetal pregnancies, with many of these admissions resulting in preterm birth. This is the first study to report the rate of pregnancy admissions for women with multifetal pregnancies, and provides a baseline for future studies of hospital use in this population.

Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy

BACKGROUND

Cervical cerclage is a well-known surgical procedure carried out during pregnancy. It involves positioning of a suture (stitch) around the neck of the womb (cervix), aiming to give a mechanical support to the cervix and thereby reducing the risk of preterm birth. The effectiveness and safety of this procedure remains controversial.

OBJECTIVES

To assess whether the use of cervical stitch in singleton pregnancy at high risk of pregnancy loss based on a woman's history and/or ultrasound finding of 'short cervix' and/or physical exam improves subsequent obstetric care and fetal outcome.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2011) and reference lists of identified studies.

SELECTION CRITERIA

We included all randomised trials of cervical suturing in singleton pregnancies carried out when pregnancy was considered to be at sufficiently high risk of pregnancy loss for cerclage to be potentially indicated. We included any study that compared cerclage with either no treatment or any alternative intervention.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion. Two review authors independently assessed risk of bias and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included 12 trials (involving 3328 women). When cerclage was compared with no treatment, there was no statistically significant difference in perinatal deaths (8.4% versus 10.7%) (risk ratio (RR) 0.78; 95% confidence interval (CI) 0.61 to 1.00; eight trials, 2391 women) and neonatal morbidity (9.6% versus 10.2%) (RR 0.95; 95% CI 0.63 to 1.43; four trials, 818 women), despite significant reduction in preterm births (average RR 0.80; 95% CI 0.69 to 0.95; nine trials, 2898 women). Cervical cerclage was associated with the higher rate of maternal side effects (vaginal discharge and bleeding, pyrexia) (average RR 2.25; 95% CI 0.89 to 5.69; three trials, 953 women). Caesarean section rates were significantly higher after cervical cerclage (RR 1.19; 95% CI 1.01 to 1.40; 8 trials, 2817 women).There was no evidence of any important differences across all prespecified clinical subgroups (history-indicated, ultrasound-indicated)One study that compared cerclage with weekly intramuscular injections of 17 α-hydroxyprogesterone caproate in women with a short cervix detected by transvaginal ultrasound, failed to reveal any obvious differences in obstetric and neonatal outcomes between the two management strategies.Two studies compared the benefits of performing cerclage based on previous history with cerclage, only if the cervix was found to be short on transvaginal ultrasound. There was no significant difference in any of the primary and secondary outcomes.

AUTHORS' CONCLUSIONS

Compared with no treatment, cervical cerclage reduces the incidence of preterm birth in women at risk of recurrent preterm birth without statistically significant reduction in perinatal mortality or neonatal morbidity and uncertain long-term impact on the baby. Ceasarean section is more likely in women who had cervical suture inserted during pregnancy.The decision on how best to minimise the risk of recurrent preterm birth in women at risk, either because of poor history of a short or dilated cervix, should be 'personalised', based on the clinical circumstances, the skill and expertise of the clinical team and, most importantly, woman's informed choice.

A nationwide survey of risk factors for stillbirth in Taiwan, 2001-2004

OBJECTIVE

The purpose of this study was to evaluate the nationwide stillbirth rate and explore the potential risk factors associated with stillbirths.

PATIENTS AND METHODS

Data from vital registrations during the time period from January 1, 2001 through to December 31, 2004 in Taiwan were used. Stillbirth was defined as fetal death with more than 20 completed weeks' gestational age (GA) or with birth weight more than 500 g if the GA was not known.

RESULTS

There were a total of 8481 stillbirths identified nationwide between January 1, 2001 and December 31, 2004. The stillbirth rate was nine per 1000 total births in the study period, and the proportionate decline was nearly 48.8% in the most recent decade. There was a significant increase in average maternal age during this period. Advanced maternal age and teenage pregnancy were independent significant risk factors for stillbirths even after accounting for the effects of medical conditions that were more likely to occur among these particular age groups. Those fetuses that had been exposed to cord prolapse, maternal cervical incompetence and oligohydramnios/polyhydramnios were especially vulnerable. By contrast, women who had foreign nationality, fetal ultrasound surveys, fetal heart beat monitoring and hastened parturition were less likely to have stillbirth.

CONCLUSION

The stillbirth rate in Taiwan has remained high despite advancements in medical care. Prenatal evaluation of high risk women may decrease the adverse fetal outcomes.

Cervical length measurement for the prediction of preterm birth in multiple pregnancies: a systematic review and bivariate meta-analysis

OBJECTIVES

To review the literature on cervical length as a predictor of preterm birth in asymptomatic women with a multiple pregnancy.

METHODS

We searched MEDLINE, Embase and reference lists of included articles to identify all studies that reported on the accuracy of cervical length for predicting preterm birth in asymptomatic women with a multiple pregnancy. We scored study characteristics and study quality, and extracted data in order to construct two-by-two tables cross-classifying cervical length and preterm delivery. Meta-analysis using a bivariate model was performed. Summary receiver-operating characteristics (ROC) curves were generated for various test characteristics and outcome definitions.

RESULTS

We found 21 studies reporting on 2757 women. There was a large variation in gestational age at measurement, cut-off point for cervical length and definition of preterm birth. The summary ROC curve indicated a good predictive capacity of short cervical length for preterm birth. Summary estimates of sensitivity and specificity for preterm birth before 34 weeks' gestation were 78% and 66%, respectively, for 35 mm, 41% and 87% for 30 mm, 36% and 94% for 25 mm and 30% and 94% for 20 mm.

CONCLUSIONS

In women with a multiple pregnancy, second-trimester cervical length is a strong predictor of preterm birth. In the absence of effective preventive strategies, there is currently no place in clinical practice for cervical length measurement in this population. However, future studies should evaluate preventive interventions in women with multiple pregnancies and a short cervix, and cervical length should be measured in any trial studying preventive strategies in multiple pregnancies.

A novel optical method to assess cervical changes during pregnancy and use to evaluate the effects of progestins on term and preterm labor

OBJECTIVE

The purpose of this study was to determine whether optical methods can estimate cervix function during pregnancy and whether progestins modify this process.

STUDY DESIGN

Photos of the external cervix of timed-pregnant rats were taken every other day from day 13 until postpartum day 5 after daily treatments with vehicle (controls) or progestin treatments (progesterone, subcutaneously or vaginally; 17-alpha-hydroxyprogesterone caproate [17P] and RU-486 subcutaneously, once on day 16). The surface area of the cervix was estimated from photos.

RESULTS

The surface area of cervix increases throughout pregnancy and reverses after delivery in controls. In the progesterone subcutaneously or 17P subcutaneously groups, increases in surface area are lower (17P group until day 19 only; P < .05). Vaginal progesterone does not prevent surface area increases. Only the progesterone subcutaneously blocked delivery. RU-486 increases the surface area of the cervix (P < .05) during preterm delivery.

CONCLUSION

An optical method is useful for quantitative assessment of the cervix and evaluation of agents that modify cervical function.

Transvaginal sonographic cervical length for the prediction of spontaneous preterm birth in twin pregnancies: a systematic review and metaanalysis

OBJECTIVE

To assess the accuracy of transvaginal sonographic cervical length (CL) in predicting spontaneous preterm birth in women with twin pregnancies.

STUDY DESIGN

Systematic review and metaanalysis of predictive test accuracy.

RESULTS

Twenty-one studies (16 in asymptomatic women and 5 in symptomatic women) with a total of 3523 women met the inclusion criteria. Among asymptomatic women, a CL

CONCLUSION

Transvaginal sonographic CL at 20-24 weeks' gestation is a good predictor of spontaneous preterm birth in asymptomatic women with twin pregnancies.

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Key Words

• cervical length
• preterm birth
• prediction
• metaanalysis
• systematic review

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MESH Headings

• Cervix Uteri/anatomy & histology
• Cervix Uteri/diagnostic imaging
• Female
• Gestational Age
• Humans
• Incidence
• Infant, Newborn
• Predictive Value of Tests
• Pregnancy
• Pregnancy Outcome
• Pregnancy, Multiple
• Premature Birth/diagnostic imaging
• Premature Birth/epidemiology
• Risk Assessment
• Twins
• Ultrasonography, Prenatal

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Grants

• ZIA HD002401 Intramural NIH HHS
• ZIA HD002401-18 Intramural NIH HHS

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Affiliation(s)

Agustín Conde-Agudelo Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/Department of Health and Human Services, Bethesda, MD, USA
Roberto Romero
Sonia S Hassan
Lami Yeo

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Global report on preterm birth and stillbirth (3 of 7): evidence for effectiveness of interventions

INTRODUCTION

Interventions directed toward mothers before and during pregnancy and childbirth may help reduce preterm births and stillbirths. Survival of preterm newborns may also be improved with interventions given during these times or soon after birth. This comprehensive review assesses existing interventions for low- and middle-income countries (LMICs).

METHODS

Approximately 2,000 intervention studies were systematically evaluated through December 31, 2008. They addressed preterm birth or low birth weight; stillbirth or perinatal mortality; and management of preterm newborns. Out of 82 identified interventions, 49 were relevant to LMICs and had reasonable amounts of evidence, and therefore selected for in-depth reviews. Each was classified and assessed by the quality of available evidence and its potential to treat or prevent preterm birth and stillbirth. Impacts on other maternal, fetal, newborn or child health outcomes were also considered. Assessments were based on an adaptation of the Grades of Recommendation Assessment, Development and Evaluation criteria.

RESULTS

Most interventions require additional research to improve the quality of evidence. Others had little evidence of benefit and should be discontinued. The following are supported by moderate- to high-quality evidence and strongly recommended for LMICs: Two interventions prevent preterm births--smoking cessation and progesterone. Eight interventions prevent stillbirths--balanced protein energy supplementation, screening and treatment of syphilis, intermittant presumptive treatment for malaria during pregnancy, insecticide-treated mosquito nets, birth preparedness, emergency obstetric care, cesarean section for breech presentation, and elective induction for post-term delivery. Eleven interventions improve survival of preterm newborns--prophylactic steroids in preterm labor, antibiotics for PROM, vitamin K supplementation at delivery, case management of neonatal sepsis and pneumonia, delayed cord clamping, room air (vs. 100% oxygen) for resuscitation, hospital-based kangaroo mother care, early breastfeeding, thermal care, and surfactant therapy and application of continued distending pressure to the lungs for respiratory distress syndrome

CONCLUSION

The research paradigm for discovery science and intervention development must be balanced to address prevention as well as improve morbidity and mortality in all settings. This review also reveals significant gaps in current knowledge of interventions spanning the continuum of maternal and fetal outcomes, and the critical need to generate further high-quality evidence for promising interventions.

Prematurity prevention: the role of cerclage

PURPOSE OF REVIEW

To summarize the literature on the value of cervical cerclage for the prevention of preterm birth and present the recent advances in its clinical application.

RECENT FINDINGS

The diagnosis of cervical insufficiency is difficult as there are no objective diagnostic criteria. Although widely used, the value of cervical cerclage is still a matter of controversy. The current literature suggests that cerclage placement can prevent preterm delivery in women with a history of at least three second-trimester losses or at least three preterm births and in those with a history of prematurity who have a cervical length of less than 25 mm in the second trimester. It is also possible to improve the perinatal outcome in patients with cervical dilation in the mid-trimester. It is not indicated in multiple pregnancies, however. Further research is needed in methods of excluding inflammation in women with cervical changes on ultrasound prior to cerclage insertion. Transabdominal or laparoscopic cerclage seems to be a promising alternative in women with a history of transvaginal cerclage failure.

SUMMARY

Strict recommendations on the proper use of cerclage cannot be easily made. Data from randomized trials do not support what the current practice in many cases is.

Reducing stillbirths: prevention and management of medical disorders and infections during pregnancy

BACKGROUND

An estimated two-thirds of the world's 3.2 million stillbirths occur antenatally, prior to labour, and are often overlooked in policy and programs. Poorly recognised, untreated or inadequately treated maternal infections such as syphilis and malaria, and maternal conditions including hypertensive disorders, are known risk factors for stillbirth.

METHODS

We undertook a systematic review of the evidence for 16 antenatal interventions with the potential to prevent stillbirths. We searched a range of sources including PubMed and the Cochrane Library. For interventions with prior Cochrane reviews, we conducted additional meta-analyses including eligible newer randomised controlled trials following the Cochrane protocol. We focused on interventions deliverable at the community level in low-/middle-income countries, where the burden of stillbirths is greatest.

RESULTS

Few of the studies we included reported stillbirth as an outcome; most that did were underpowered to assess this outcome. While Cochrane reviews or meta-analyses were available for many interventions, few focused on stillbirth or perinatal mortality as outcomes, and evidence was frequently conflicting. Several interventions showed clear evidence of impact on stillbirths, including heparin therapy for certain maternal indications; syphilis screening and treatment; and insecticide-treated bed nets for prevention of malaria. Other interventions, such as management of obstetric intrahepatic cholestasis, maternal anti-helminthic treatment, and intermittent preventive treatment of malaria, showed promising impact on stillbirth rates but require confirmatory studies. Several interventions reduced known risk factors for stillbirth (e.g., anti-hypertensive drugs for chronic hypertension), yet failed to show statistically significant impact on stillbirth or perinatal mortality rates. Periodontal disease emerged as a clear risk factor for stillbirth but no interventions have reduced stillbirth rates.

CONCLUSION

Evidence for some newly recognised risk factors for stillbirth, including periodontal disease, suggests the need for large, appropriately designed randomised trials to test whether intervention can minimise these risks and prevent stillbirths. Existing evidence strongly supports infection control measures, including syphilis screening and treatment and malaria prophylaxis in endemic areas, for preventing antepartum stillbirths. These interventions should be incorporated into antenatal care programs based on attributable risks and burden of disease.

Novel developments on cervical length screening and progesterone for preventing preterm birth

Cervical length (CL) measured by transvaginal ultrasound is an effective screening test for the prevention of preterm birth (PTB). The criteria for an effective screening test are all met by CL. It studies an important condition (PTB); it is safe and acceptable by >99% of women; it recognises an early asymptomatic phase that precedes PTB by many weeks; it has a well-described technique, is reproducible, is predictive of PTB in all populations studies so far; and, perhaps most importantly, it has been shown that 'early' treatment is effective in prevention. These two interventions, effective only in specific populations, are ultrasound-indicated cerclage and vaginal progesterone.