Vaginal progesterone in women with an asymptomatic sonographic short cervix in the midtrimester decreases preterm delivery and neonatal morbidity: a systematic review and metaanalysis of individual patient data

Vaginal progesterone is as effective as cervical cerclage to prevent preterm birth in women with a singleton gestation, previous spontaneous preterm birth, and a short cervix: updated indirect comparison meta-analysis

BACKGROUND

An indirect comparison meta-analysis published in 2013 reported that both vaginal progesterone and cerclage are equally efficacious for preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic short cervix. The efficacy of vaginal progesterone has been challenged after publication of the OPPTIMUM study. However, this has been resolved by an individual patient-data meta-analysis (Am J Obstet Gynecol. 2018;218:161-180).

OBJECTIVE

To compare the efficacy of vaginal progesterone and cerclage in preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix.

DATA SOURCES

MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to March 2018); Cochrane databases, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials comparing vaginal progesterone to placebo/no treatment or cerclage to no cerclage in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic cervical length <25 mm.

STUDY APPRAISAL AND SYNTHESIS METHODS

Updated systematic review and adjusted indirect comparison meta-analysis of vaginal progesterone vs cerclage using placebo/no cerclage as the common comparator. The primary outcomes were preterm birth <35 weeks of gestation and perinatal mortality. Pooled relative risks (RRs) with 95% confidence intervals were calculated.

RESULTS

Five trials comparing vaginal progesterone vs placebo (265 women) and 5 comparing cerclage vs no cerclage (504 women) were included. Vaginal progesterone, compared to placebo, significantly reduced the risk of preterm birth <35 and <32 weeks of gestation, composite perinatal morbidity/mortality, neonatal sepsis, composite neonatal morbidity, and admission to the neonatal intensive care unit (RRs from 0.29 to 0.68). Cerclage, compared to no cerclage, significantly decreased the risk of preterm birth <37, <35, <32, and <28 weeks of gestation, composite perinatal morbidity/mortality, and birthweight <1500 g (RRs from 0.64 to 0.70). Adjusted indirect comparison meta-analyses did not show statistically significant differences between vaginal progesterone and cerclage in the reduction of preterm birth or adverse perinatal outcomes.

CONCLUSION

Vaginal progesterone and cerclage are equally effective for preventing preterm birth and improving perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix. The choice of treatment will depend on adverse events and cost-effectiveness of interventions and patient/physician's preferences.

Controversies about the Secondary Prevention of Spontaneous Preterm Birth

Preterm birth is one of the major global health problems and part of the Millennium Development goals because of the associated high number of perinatal or neonatal mortality and long-term risks of neurodevelopmental and metabolic diseases. Transvaginal sonography has meanwhile been established as a screening tool for spontaneous preterm birth despite its relatively low sensitivity when considering only the cervical length. Vaginal progesterone has been shown to reduce prematurity rates below 34 weeks in a screening population of singleton pregnancies. Up to now, no positive long-term effect could be demonstrated after 2 years. It seems to have no benefit to prolong pregnancies after a period of preterm contractions and in risk patients without cervical shortening. Meta-analyses still demonstrate conflicting results dependent on quality criteria used for selection. A cerclage is only indicated in singleton pregnancies with previous spontaneous preterm birth and a combined cervical shortening in the current pregnancy. Nevertheless, the short- and long-term outcome has never been evaluated, whereas maternal complications may be increased. There is no evidence for a prophylactic cervical cerclage in twin pregnancies even in cases with cervical shortening. Emergency cerclage remains an indication after individual counseling. The effect of a cervical pessary in singleton pregnancy seems to be more pronounced in studies where a few investigators with increasing experience have treated and followed the patients at risk for preterm birth. Mainly in twin pregnancies, pessary treatment seems to be promising compared to other treatment options of secondary prevention when the therapy is started at early stages of precocious cervical ripening. At present, several international trials with the goal to reduce global rates of prematurity are in progress which will hopefully allow to specify the indications and methods of intervention for certain subgroups. When trials are summarized, prospective meta-analyses carry a lower risk of bias than the meanwhile uncontrolled magnitude of retrospective meta-analyses with conflicting results.

Prevention of preterm birth with pessary in singletons (PoPPS): randomized controlled trial

OBJECTIVE

To determine if pessary use prevents preterm birth (PTB) in women with singleton pregnancy, with short cervical length (CL) measured on transvaginal sonography (TVS) and without prior spontaneous PTB (sPTB).

METHODS

This was an open-label multicenter randomized trial of asymptomatic women presenting at 18 + 0 to 23 + 6 weeks' gestation with a singleton pregnancy, CL ≤ 25 mm on TVS and no prior sPTB. sPTB included those with spontaneous onset of labor and those with rupture of membranes prior to labor. Subjects were randomized to receive either a Bioteque cup pessary or no pessary. Pessaries were inserted by trained maternal-fetal medicine staff. Vaginal progesterone was recommended to women with CL ≤ 20 mm. The primary outcome was PTB < 37 weeks. A sample size of 121 women in each group (n = 242) was needed to detect a reduction in the primary outcome from 30% in the no-pessary group to 15% in the pessary group. The trial was stopped early before complete enrollment.

RESULTS

Between 17 March 2014 and 29 July 2016, 17 383 women underwent CL measurement on TVS. Of these, 422 (2.4%) had CL ≤ 25 mm and 391 (92.7%) met the full eligibility criteria, of which 122 (31.2%) agreed to randomization. Sixty-one (50%) women were randomized to the pessary group and 61 (50%) to the no-pessary group. Baseline characteristics were similar between the groups. There were no significant differences between the pessary and no-pessary groups in the rate of PTB < 37 weeks (43% vs 40%; relative risk 1.09; 95% CI, 0.71-1.68) or in secondary outcomes, such as rate of PTB < 34 weeks, rate of PTB < 28 weeks, gestational age at delivery, birth weight and rate of composite adverse neonatal outcome.

CONCLUSIONS

Cervical pessary use was not associated with prevention of PTB in women with a singleton pregnancy, short CL on TVS and no prior sPTB in this small, underpowered randomized controlled trial. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Mid-trimester sonographic cervical consistency index to predict spontaneous preterm birth in a low-risk population

OBJECTIVES

To investigate the effectiveness of mid-trimester sonographic cervical consistency index (CCI) for the prediction of spontaneous preterm birth (sPTB) in low-risk pregnancies and to compare its performance with that of mid-trimester sonographic cervical-length (CL) measurement.

METHODS

This was a prospective cohort study of women with a singleton pregnancy examined by ultrasound at 19 + 0 to 24 + 6 weeks' gestation. All women underwent transvaginal ultrasound examination of the cervix, but CCI and CL were measured, offline, only in women without a risk factor for sPTB. Staff and participants were blinded to CL and CCI results. CCI was obtained by calculating the ratio between the anteroposterior diameter of the uterine cervix at maximum compression and at rest. The primary outcome was prediction of sPTB before 37 + 0 weeks. Receiver-operating characteristics (ROC) curves were produced and sensitivity and specificity were calculated for the optimal cut-off based on the ROC curve and for the 1^st , 5^th and 10^th centiles of CCI and CL. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to estimate intra- and interobserver agreement and reliability for measurement of CCI and CL.

RESULTS

Of the 749 women who underwent ultrasound examination of the cervix, 532 were included for analysis. The rates of sPTB before 37 + 0 and before 34 + 0 weeks were 4.1% (22/532) and 1.3% (7/532), respectively. The rates of short cervix < 25 mm and ≤ 20 mm were 0.9% (5/532) and 0.4% (2/532), respectively. The area under the ROC curve (AUC) with regard to predicting sPTB before 37 + 0 weeks was 0.84 (95% CI, 0.75-0.93) for CCI compared with 0.68 (95% CI, 0.56-0.81) for CL (P = 0.03). The optimal cut-off based on the ROC curve was 64.6% for CCI (sensitivity, 77.3%; specificity, 82.7%) and that for CL was 37.9 mm (sensitivity, 72.7%; specificity, 61.2%). The AUC with regard to predicting sPTB before 34 + 0 weeks was 0.87 (95% CI, 0.71-1.0) for CCI compared with 0.71 (95% CI, 0.47-0.94) for CL (P = 0.25). The optimal cut-off based on the ROC curve was 63.6% for CCI (sensitivity, 85.7%; specificity, 84.0%) and that for CL was 37.9 mm (sensitivity, 85.7%; specificity, 61.3%). Intraobserver ICC was > 0.90 both for CCI and CL, while interobserver ICC was 0.89 for CCI and 0.90 for CL.

CONCLUSIONS

Second-trimester CCI is a better predictor of sPTB < 37 weeks in low-risk pregnancies than is CL. External validation is needed as well as studies assessing the value of CCI as a screening tool in unselected and high-risk populations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

The association of different progesterone preparations with preterm birth prevention

Objective: We aimed to compare the efficacy of commonly available progesterone preparations for preterm birth prevention. Methods: A retrospective cohort study of all women treated with progesterone to prevent preterm birth and delivered in a single university-affiliated tertiary medical-center. Four progesterone preparations were compared: vaginal Endometrin 100 mg twice daily, vaginal Crinone 8% gel 90 mg daily, vaginal Utrogestan 200 mg daily, and intramuscular 17α-hydroxyprogesterone caproate (17-OHPC) 250 mg weekly. All women were considered at risk for preterm birth according to: prior preterm birth or cervical length below 25 mm measured during the second trimester. Significant maternal morbidity, pregnancy achieved by artificial reproductive technique and cerclage placement were excluded. Primary outcome was the rate of preterm birth prior to 37 weeks of gestation. Results: Overall, 422 women were allocated to four study groups according to progesterone preparation: Endometrin 175 (41.5%), Crinone 73 (17.3%), Utrogestan 154 (36.5%), and 17-OHPC 20 (4.7%). Rates of preterm birth prior to 37 gestational weeks were lowest on the Endometrin treatment group (12.6 versus 20.5, 17.5, and 35% in the rest, p = .05). Multivariate analysis revealed that the progesterone preparation was associated with preterm birth prior to 37 gestational weeks (LR = 8.3, p = .004). The need for maternal red blood cells transfusion was significantly higher in the Endometrin subgroup (4% versus 0 in all others, p = .018). This finding remained significant after adjustment to potential confounders (LR 16.44, p < .001). Neonatal outcomes did not differ between groups. Conclusions: Different progesterone preparations prescribed to women at risk, may possess different efficacy in preventing preterm delivery prior to 37 weeks of gestation.

A randomised trial to compare 200 mg micronised progesterone effervescent vaginal tablet daily with 250 mg intramuscular 17 alpha hydroxy progesterone caproate weekly for prevention of recurrent preterm birth

For prevention of a recurrent preterm birth (PTB), intramuscular 17-α-hydroxy progesterone caproate (IM 17 OHPC) weekly is recommended. Vaginal progesterone is preferred for women at risk for PTB due to a short cervical length, but may be useful in women with a prior PTB. However, there is no consensus about the optimal vaginal formulation or its efficacy as compared to 17 OHPC to prevent recurrent PTB. We randomised 100 women with a singleton pregnancy between 16 and 24 weeks of gestation and ≥ one prior spontaneous PTB, of a singleton (>16 to <37 weeks of gestation) to receive the 200 mg vaginal progesterone effervescent tablet daily (Group A) or IM 17-OHPC, 250 mg weekly (Group B) till 37 weeks of gestation or delivery. The spontaneous PTB rate of <37 weeks was similar (20% in Group A and 20.8% in Group B, p =  .918). The PTB rate of <34 weeks or <28 weeks were also comparable. The mean birth weight and other neonatal outcomes were similar in the two groups. Two neonates in Group A and four neonates in Group B required NICU admission, one of whom (Group B) died due to prematurity. Twenty percent of women in Group A and 29.2% in Group B reported adverse effects from their respective study medications (p =  .408, NS). Thus, there did not appear to be a difference between vaginal progesterone and 17-OHPC when used for the prevention of a recurrent PTB. Impact statement What is already known on this subject? Progesterone administration is useful for prevention of a recurrent preterm birth (PTB) and these women are prescribed the intramuscular 17-α-hydroxy progesterone caproate (IM 17 OHPC), 250 mg, weekly. Some studies found that vaginal progesterone (once daily) is also beneficial in these women, but there is no consensus regarding its efficacy when compared to 17 OHPC, or its optimal formulation and dose. What do the results of this study add? In the present study, 100 women with a singleton pregnancy between 16 and 24 weeks of gestation and ≥ one prior spontaneous singleton PTB or mid-trimester abortion were randomised to receive 200 mg of vaginal progesterone effervescent tablet daily (Group A) or 250 mg IM 17-OHPC weekly (Group B) till 37 weeks of gestation or delivery. The spontaneous PTB rate <37 weeks was similar in the two groups (20% in Group A and 20.8% in Group B, p = .918). The PTB rate <34 weeks or <28 weeks were also comparable. The mean birth weight and other neonatal outcomes were similar. Twenty percent of women in Group A and 29.2% of women in Group B reported adverse effects from their respective study medications (p = .408, NS). Thus, there did not appear to be a difference between the vaginal progesterone effervescent tablet and 17-OHPC when used for the prevention of a recurrent PTB. What are the implications of these findings for clinical practice and/or further research? The vaginal progesterone effervescent tablet may be a suitable alternative to IM 17 OHPC to prevent recurrent PTB. Future studies should identify the most appropriate route (IM or vaginal) and vaginal progesterone formulation for PTB prevention in women at risk for a recurrent PTB and in women with a short cervical length.

Routine second trimester cervical length screening in low risk women identified women at risk of a 'very' preterm birth but did not reduce the preterm birth rate: a randomised study from India

Women (n = 300) at 'low risk' for a preterm birth (PTB), a singleton pregnancy and for a 16-24 week period of gestation (POG) were randomised to undergo cervical length (CL) measurement by transvaginal sonography (TVS) or not. The aim was to see if routine CL measurement and treatment of a short CL reduced the PTB rate. 'Low risk' was defined by an absence of a prior abortion or PTB of a singleton infant (>16 to <37 weeks) due to a spontaneous preterm labour (PTL) or a preterm pre-labour rupture of membranes (pPROM). The PTB rate was similar in the screened and unscreened group (10.3 and 8%, respectively, p = .433). In the screened group, women who delivered at 'term' or 'moderate to late' preterm (32 to <37 weeks) had a significantly higher mean CL (3.46 ± 0.41 and 3.48 ± 0.65 cm, respectively) than the women who delivered 'very' preterm (28 to 31 + 6 weeks; 2.05 ± 0.5 cm; p = .01). A short CL ≤2.5 cm was observed in two primigravidas (2/147 or 1.3%). They delivered at 28 + 3 and 30 + 6 weeks POG, respectively, despite treatment with vaginal progesterone and rescue cerclage in one. Their neonates were discharged in a good condition. In our low risk cohort, a routine second trimester CL measurement did not reduce the overall PTB rate. However, it identified two primigravidas at risk of having a 'very' PTB.Clinical Trials Registry (CTRI), India: Registration number CTRI/2016/01/010438 Impact statement What is already known on this subject? In women with a singleton pregnancy who are at a 'low risk' for preterm birth (PTB), a short cervical length (CL) at mid trimester measured by transvaginal sonography (TVS) identifies those at risk for a PTB. This risk may be reduced by the treatment with vaginal progesterone. At present, though evidence in favour of CL measurement in low-risk women exists, it is not established as a part of antenatal care. What do the results of this study add? A routine second trimester CL measurement in low risk women did not reduce the PTB rate. However, screening for a short CL helped to identify two primigravidas at risk for a 'very' PTB. It may be possible that detection and treatment of a short CL averted an 'extremely' PTB (<28 weeks) in these two women. What are the implications of these findings for clinical practice and/or further research? Future studies should assess the outcome of women with a short mid-trimester CL to see whether its treatment resulted in pregnancy prolongation and an improved neonatal outcome.

Adjuvant administration of 17-α-hydroxy-progesterone caproate in women with three or more second trimester pregnancy losses undergoing cervical cerclage is no more effective than cerclage alone

OBJECTIVE

To investigate the role of adjuvant 17-α-hydroxy-progesterone caproate (17OHP-C) in reducing the risk of preterm delivery <34 weeks and adverse perinatal outcomes in women with ≥3 second trimester pregnancy losses attributed to cervical insufficiency undergoing prophylactic cerclage.

MATERIAL AND METHODS

Retrospective cohort study of women with prophylactic cerclage placed between 2006 and 2014 divided into a cohort of (i) those receiving adjuvant 17OHP-C (n=43), and (ii) controls with cerclage alone (n=59).

RESULTS

Demographic characteristics were comparable in both groups. There was no significant difference in gestational age at delivery between the cerclage-17OHP-C group (33.4±5.6 weeks) and the cerclage-alone group (34.4±4.6 weeks); P=0.33. We noted a non-significant increase for deliveries <34 weeks in the cerclage-17OHP-C group (44.2%) compared to controls (28.8%) which remained non-significant after adjusting for confounders; P=0.46. There was no statistically significant difference in the rate of delivery <37, 32, 28 and 24 weeks. Adverse neonatal outcomes were comparable in both groups (cerclage-17OHP-C 48.8% vs. cerclage-alone 39%); P=0.43.

CONCLUSION

Intramuscular 17OHP-C in combination with prophylactic cerclage in women with cervical insufficiency and ≥3 second trimester pregnancy losses had no synergistic effect in reducing the rate of recurrent preterm birth or improving perinatal outcomes.

Potentially Preventable Stillbirth in a Diverse U.S. Cohort

OBJECTIVE

To estimate the proportion of potentially preventable stillbirths in the United States.

METHODS

We conducted a secondary analysis of 512 stillbirths with complete evaluation enrolled in the Stillbirth Collaborative Research Network from 2006 to 2008. The Stillbirth Collaborative Research Network was a multisite, geographically, racially, and ethnically diverse, population-based case-control study of stillbirth in the United States. Cases of stillbirth underwent standard evaluation that included maternal interview, medical record abstraction, biospecimen collection, postmortem examination, placental pathology, and clinically recommended evaluation. Each stillbirth was assigned probable and possible causes of death using the Initial Causes of Fetal Death algorithm system. For this analysis, we defined potentially preventable stillbirths as those occurring in nonanomalous fetuses, 24 weeks of gestation or greater, and weighing 500 g or greater that were 1) intrapartum, 2) the result of medical complications, 3) the result of placental insufficiency, 4) multiple gestation (excluding twin-twin transfusion), 5) the result of spontaneous preterm birth, or 6) the result of hypertensive disorders of pregnancy.

RESULTS

Of the 512 stillbirths included in our cohort, causes of potentially preventable stillbirth included placental insufficiency (65 [12.7%]), medical complications of pregnancy (31 [6.1%]), hypertensive disorders of pregnancy (20 [3.9%]), preterm labor (16 [3.1%]), intrapartum (nine [1.8%]), and multiple gestations (four [0.8%]). Twenty-seven stillbirths fit two or more categories, leaving 114 (22.3%) potentially preventable stillbirths.

CONCLUSION

Based on our definition, almost one fourth of stillbirths are potentially preventable. Given the predominance of placental insufficiency among stillbirths, identification and management of placental insufficiency may have the most immediate effect on stillbirth reduction.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

Long-term childhood outcomes after interventions for prevention and management of preterm birth

Globally, preterm birth rates are rising and have a significant impact on neonatal morbidity and mortality. Preterm birth remains difficult to prevent and a number of strategies for preterm birth prevention (progesterone, cervical pessaries, cervical cerclage, tocolytics, and antibiotics) have been identified. While some of these show more promise, there is a paucity of evidence regarding the long-term effects of these strategies on childhood outcomes. Strategies used to improve the health of babies if born preterm, such as antenatal magnesium sulfate for fetal neuroprotection and antenatal corticosteroids for fetal lung maturation, show evidence of short-term benefit but lack large-scale follow-up data of long-term childhood outcomes. Future research on preterm birth interventions should include long-term follow-up of the children, ideally with similar outcome measures to allow for future meta-analyses.

Evaluating progestogens for prevention of preterm birth international collaborative (EPPPIC) individual participant data (IPD) meta-analysis: protocol

BACKGROUND

Preterm birth is the most common cause of death and harm to newborn babies. Babies that are born early may have difficulties at birth and experience health problems during early childhood. Despite extensive study, there is still uncertainty about the effectiveness of progestogen (medications that are similar to the natural hormone progesterone) in preventing or delaying preterm birth, and in improving birth outcomes. The Evaluating Progestogen for Prevention of Preterm birth International Collaborative (EPPPIC) project aims to reduce uncertainty about the specific conditions in which progestogen may (or may not) be effective in preventing or delaying preterm birth and improving birth outcomes.

METHODS

The design of the study involves international collaborative individual participant data meta-analysis comprising systematic review, re-analysis, and synthesis of trial datasets. Inclusion criteria are as follows: randomized controlled trials comparing progestogen versus placebo or non-intervention, or comparing different types of progestogen, in asymptomatic women at risk of preterm birth. Main outcomes are as follows; fetal/infant death, preterm birth or fetal death (<=37 weeks, <=34 weeks, <= 28 weeks), serious neonatal complications or fetal/infant death, neurosensory disability (measured at 18 months or later) or infant/child death, important maternal morbidity, or maternal death. In statistical methods, IPD will be synthesized across trials using meta-analysis. Both 'two-stage' models (where effect estimates are calculated for each trial and subsequently pooled in a meta-analysis) and 'one-stage' models (where all IPD from all trials are analyzed in one step, while accounting for the clustering of participants within trials) will be used. If sufficient suitable data are available, a network meta-analysis will compare all types of progesterone and routes of administration extending the one-stage models to include multiple treatment arms.

DISCUSSION

EPPPIC is an international collaborative project being conducted by the forming EPPPIC group, which includes trial investigators, an international secretariat, and the research project team. Results, which are intended to contribute to improvements in maternal and child health, are expected to be publicly available in mid 2018.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017068299.

Accuracy of a combined insulin-like growth factor-binding protein-1/interleukin-6 test (Premaquick) in predicting delivery in women with threatened preterm labor

PURPOSE

To determine values of combinations of interleukin-6 (IL-6)/cervical native insulin-like growth factor-binding protein-1 (IGFBP-1)/total IGFBP-1 (Premaquick©) in predicting spontaneous deliveries and spontaneous exclusive preterm deliveries in women with threatened preterm labor.

METHODS

Women with singleton pregnancies between gestation age (GA) of 24 weeks and 36 weeks and 6 days with preterm labor were recruited during a prospective multicenter study. Premaquick© was positive when at least two of three biomarkers were positive. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were estimated for both prediction of spontaneous deliveries and spontaneous exclusive preterm deliveries.

RESULTS

Ninety-seven (99.0%) out of 98 women enrolled were analyzed. Based on delivery status 7/14 days post-enrollment of general study population, Premaquick© had a sensitivity of 87.1/85.7%, a specificity of 92.4/96.8%, a PPV of 84.4/93.8% and a NPV of 93.9/92.3% for prediction of spontaneous delivery. Predictive accuracy of Premaquick© test in relation to days of enrollment were: 90.7% (≤7 days) and 92.8% (≤14 days). For women enrolled at GA <35 weeks, Premaquick© had a sensitivity of 100.0/87.5%, a specificity of 94.1/96.9%, a PPV of 70.5/87.5%, a NPV of 100.0/96.9% and an accuracy of 95.0/95.0% for prediction of preterm delivery within 7/14 days of enrollment, respectively. PPV was most significantly different in both groups when outcomes were compared between 2 days and 14 days post-enrollment (P<0.001).

CONCLUSION

This novel triple biomarker model of native and total IGFBP-1 and IL-6 appears to be an accurate test in predicting spontaneous deliveries and spontaneous exclusive preterm deliveries in threatened preterm labor in singleton pregnancies.

The effect of prenatal vaginal progesterone on cervical length in nonselected twin pregnancies

PURPOSE

The aim of this study was to investigate the influence of vaginal progesterone on cervical length (CL) in asymptomatic nonselected twin gestations.

METHODS

This was a secondary analysis of a randomized, double-blind, placebo-controlled trial of twin pregnancies exposed to vaginal progesterone or placebo. The CL was examined at six different time periods: 18-21⁺⁶ weeks (T1), 21-23⁺⁶ weeks (T2), 24-26⁺⁶ weeks (T3), 27-29⁺⁶ weeks (T4), 30-32⁺⁶ weeks (T5) and 33-34⁺⁶ weeks (T6). The rate of cervical shortening per week and the percent cervical shortening were compared between the groups, with analyses of the entire cohort and of those who delivered spontaneously according to gestational age at birth.

RESULTS

The final analysis included 184 women in the progesterone group and 188 women in the placebo group. The baseline characteristics were similar in both groups. No differences in cervical shortening in terms of absolute value or percent shortening were observed between the groups at each time period or throughout gestation. Furthermore, no difference was found in cervical shortening for those who delivered spontaneously.

CONCLUSION

Cervical shortening in asymptomatic nonselected twin pregnancies occurred at a similar rate, regardless of vaginal progesterone treatment.

Cerclage for sonographic short cervix in singleton gestations without prior spontaneous preterm birth: systematic review and meta-analysis of randomized controlled trials using individual patient-level data

OBJECTIVE

The aim of this systematic review and meta-analysis was to quantify the efficacy of cervical cerclage in preventing preterm birth (PTB) in asymptomatic singleton pregnancies with a short mid-trimester cervical length (CL) on transvaginal sonography (TVS) and without prior spontaneous PTB.

METHODS

Electronic databases were searched from inception of each database until February 2017. No language restrictions were applied. All randomized controlled trials (RCTs) of asymptomatic singleton pregnancies without prior spontaneous PTB, found to have short CL < 25 mm on mid-trimester TVS and then randomized to management with either cerclage or no cerclage, were included. Corresponding authors of all the included trials were contacted to obtain access to the data and perform a meta-analysis of individual patient-level data. Data provided by the investigators were merged into a master database constructed specifically for the review. Primary outcome was PTB < 35 weeks. Summary measures were reported as relative risk (RR) with 95% CI. The quality of the evidence was assessed using the GRADE approach.

RESULTS

Five RCTs, including 419 asymptomatic singleton gestations with TVS-CL < 25 mm and without prior spontaneous PTB, were analyzed. In women who were randomized to the cerclage group compared with those in the control group, no statistically significant differences were found in PTB < 35 (21.9% vs 27.7%; RR, 0.88 (95% CI 0.63-1.23); I²  = 0%; five studies, 419 participants), < 34, < 32, < 28 and < 24 weeks, gestational age at delivery, preterm prelabor rupture of membranes (PPROM) and neonatal outcomes. In women who received cerclage compared with those who did not, planned subgroup analyses revealed a significantly lower rate of PTB < 35 weeks in women with TVS-CL < 10 mm (39.5% vs 58.0%; RR, 0.68 (95% CI, 0.47-0.98); I²  = 0%; five studies; 126 participants) and in women who received tocolytics (17.5% vs 32.7%; RR, 0.54 (95% CI, 0.31-0.93); I²  = 0%; four studies; 169 participants) or antibiotics (18.3% vs 31.5%; RR, 0.58 (95% CI, 0.33-0.98); I²  = 0%; three studies; 163 participants) as additional therapy to cerclage. The quality of evidence was downgraded two levels because of serious imprecision and indirectness, and therefore was judged as low.

CONCLUSIONS

In singleton gestations without prior spontaneous PTB but with TVS-CL < 25 mm in the second trimester, cerclage does not seem to prevent preterm delivery or improve neonatal outcome. However, in these pregnancies, cerclage seems to be efficacious at lower CLs, such as < 10 mm, and when tocolytics or antibiotics are used as additional therapy, requiring further studies in these subgroups. Given the low quality of evidence, further well-designed RCTs are needed to confirm the findings of this study. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Characterization of Maternal and Fetal CYP3A-Mediated Progesterone Metabolism

INTRODUCTION

Progesterone is critical for maintaining pregnancy and onset of labor. We evaluated CYP450-mediated progesterone meta-bolism, specifically the contribution of CYP3A isoforms.

MATERIALS AND METHODS

In vitro progesterone metabolism was characterized in human liver microsomes (HLMs) with and without selective cytochrome P450 inhibitors and in recombinant CYP3A4, CYP3A5, and CYP3A7. 6β-hydroxyprogesterone (6β-OHP) and 16α-hydroxyprogesterone (16α-OHP) metabolites were quantified by HPLC/UV and fit to the Michaelis-Menten equation to determine Km and Vmax. The effect of CYP3A5 expression on progesterone clearance was determined by in vitro in vivo extrapolation.

RESULTS

Ketoconazole inhibited formation of both 6β-OHP and 16α-OHP more than 95%. 6β-OHP and 16α-OHP were both produced by CYP3A4 (2.3 and 1.3 µL/min/pmol, respectively) to a greater extent than by CYP3A5 (0.09 and 0.003 µL/min/pmol) and CYP3A7 (0.004 and 0.003 µL/min/pmol).

CONCLUSIONS

Maternal clearance of progesterone by hepatic CYP450's is driven primarily by CYP3A4, with limited contributions from CYP3A5 and CYP3A7.

Use of progesterone supplement therapy for prevention of preterm birth: review of literatures

Preterm birth (PTB) is one of the most common complications during pregnancy and it primarily accounts for neonatal mortality and numerous morbidities including long-term sequelae including cerebral palsy and developmental disability. The most effective treatment of PTB is prediction and prevention of its risks. Risk factors of PTB include history of PTB, short cervical length (CL), multiple pregnancies, ethnicity, smoking, uterine anomaly and history of curettage or cervical conization. Among these risk factors, history of PTB, and short CL are the most important predictive factors. Progesterone supplement therapy is one of the few proven effective methods to prevent PTB in women with history of spontaneous PTB and in women with short CL. There are 2 types of progesterone therapy currently used for prevention of PTB: weekly intramuscular injection of 17-alpha hydroxyprogesterone caproate and daily administration of natural micronized progesterone vaginal gel, vaginal suppository, or oral capsule. However, the efficacy of progesterone therapy to prevent PTB may vary depending on the administration route, form, dose of progesterone and indications for the treatment. This review aims to summarize the efficacy and safety of progesterone supplement therapy on prevention of PTB according to different indication, type, route, and dose of progesterone, based on the results of recent randomized trials and meta-analysis.

Complement activation, a threat to pregnancy

Pregnancy poses a challenge for the immune systems of placental mammals. As fetal tissues are semi-allogeneic and alloantibodies that commonly develop in the mother, the fetus and the placenta might be subject to complement-mediated immune attack with the potential risk of adverse pregnancy outcomes. Here, I describe how the use of animal models was pivotal in demonstrating that complement inhibition at the fetomaternal interface is essential for a successful pregnancy. Studies in animals also helped the identification of uncontrolled complement activation as a crucial effector in the pathogenesis of recurrent miscarriages, intrauterine growth restriction, preeclampsia, and preterm birth. Clinical studies employing complement biomarkers in plasma and urine showed an association between dysregulation of the complement system and adverse pregnancy outcomes. A better understanding of the role of the complement system in pregnancy complications will allow a rational approach to manipulate its activation as a potential therapeutic strategy with the goal of protecting pregnancies and improving long-term outcomes for mother and child.

Pessary or Progesterone to Prevent Preterm delivery in women with short cervical length: the Quadruple P randomised controlled trial

BACKGROUND

Preterm birth is in quantity and in severity the most important topic in obstetric care in the developed world. Progestogens and cervical pessaries have been studied as potential preventive treatments with conflicting results. So far, no study has compared both treatments.

METHODS/DESIGN

The Quadruple P study aims to compare the efficacy of vaginal progesterone and cervical pessary in the prevention of adverse perinatal outcome associated with preterm birth in asymptomatic women with a short cervix, in singleton and multiple pregnancies separately. It is a nationwide open-label multicentre randomized clinical trial (RCT) with a superiority design and will be accompanied by an economic analysis. Pregnant women undergoing the routine anomaly scan will be offered cervical length measurement between 18 and 22 weeks in a singleton and at 16-22 weeks in a multiple pregnancy. Women with a short cervix, defined as less than, or equal to 35 mm in a singleton and less than 38 mm in a multiple pregnancy, will be invited to participate in the study. Eligible women will be randomly allocated to receive either progesterone or a cervical pessary. Following randomization, the silicone cervical pessary will be placed during vaginal examination or 200 mg progesterone capsules will be daily self-administered vaginally. Both interventions will be continued until 36 weeks gestation or until delivery, whichever comes first. Primary outcome will be composite adverse perinatal outcome of perinatal mortality and perinatal morbidity including bronchopulmonary dysplasia, intraventricular haemorrhage grade III and IV, periventricular leukomalacia higher than grade I, necrotizing enterocolitis higher than stage I, Retinopathy of prematurity (ROP) or culture proven sepsis. These outcomes will be measured up until 10 weeks after the expected due date. Secondary outcomes will be, among others, time to delivery, preterm birth rate before 28, 32, 34 and 37 weeks, admission to neonatal intensive care unit, maternal morbidity, maternal admission days for threatened preterm labour and costs.

DISCUSSION

This trial will provide evidence on whether vaginal progesterone or a cervical pessary is more effective in decreasing adverse perinatal outcome in both singletons and multiples.

TRIAL REGISTRATION

Trial registration number: NTR 4414 . Date of registration January 29th 2014.

Preterm birth prevention-Time to PROGRESS beyond progesterone

In a Perspective, Jane Norman and Phillip Bennett argue that it is time to explore alternatives to progesterone for preventing preterm birth.

The cytokine network in women with an asymptomatic short cervix and the risk of preterm delivery

PROBLEM

To characterize the amniotic fluid (AF) inflammatory-related protein (IRP) network in patients with a sonographic short cervix (SCx) and to determine its relation to early preterm delivery (ePTD).

METHOD OF STUDY

A retrospective cohort study included women with a SCx (≤25 mm; n=223) who had amniocentesis and were classified according to gestational age (GA) at diagnosis and delivery (ePTD <32 weeks of gestation).

RESULTS

(i) In women with a SCx ≤ 22 1/7 weeks, the concentration of most IRPs increased as the cervix shortened; those with ePTD had a higher rate of increase in MIP-1α, MCP-1, and IL-6 concentrations than those delivering later; and (ii) the concentration of most IRPs and the correlation between several IRP pairs were higher in the ePTD group than for those delivering later.

CONCLUSION

Women with a SCx at 16-22 1/7 weeks have a unique AF cytokine network that correlates with cervical length at diagnosis and GA at delivery. This network may aid in predicting ePTD.

Retrospective Cohort Study of Cervical Pessary Use in Women with Short Cervix at Risk of Preterm Delivery

OBJECTIVE

A paucity of effective interventions exists for the prevention of preterm birth (PTB). Renewed interest has focused on cervical pessaries, which have the benefits of being inexpensive, nonsurgical, and easily inserted and removed. In this study, we aim to describe our experience with this device in a Canadian tertiary care centre. Primary outcomes were rates of spontaneous or iatrogenic PTB before 37, 34, and 28 weeks gestation in pregnancies complicated by short cervix treated with cervical pessary.

METHODS

This was a retrospective cohort study of women with singleton, twin, and triplet pregnancies with pessary placement from August 2013 to March 2015 in the Urogynecology Clinic at the Lois Hole Hospital for Women in Edmonton, AB. Included women were deemed to be at high risk of PTB due to short cervix (≤25 mm) found on ultrasound.

RESULTS

Among 115 women included, pessaries were placed at a mean gestation of 25.3 weeks. Forty-nine singleton women (52.7%) delivered at term. Of these deliveries, 75% were spontaneous. Rates of PTB before 34 and 28 weeks gestation for all deliveries, respectively, were 37.4% and 10.4%. Removal data were available for 87.8% of patients, and the pessary remained in situ for a mean of 48 days.

CONCLUSION

In this study's high-risk obstetrical population, the rates of preterm birth remained high. The effectiveness of pessary use, particularly when compared to other preventative strategies, remains a topic in need of further investigation. To our knowledge, this is the first study to contribute pessary data from a Canadian population.

Progesterone in women with arrested premature labor, a report of a randomised clinical trial and updated meta-analysis

BACKGROUND

Progesterone may be effective in prevention of premature birth in some high risk populations. Women with arrested premature labor are at risk of recurrent labor and maintenance therapy with standard tocolytics has not been successful.

METHODS

Randomized double blinded clinical trial of daily treatment with 200 mg vaginal progesterone in women with arrested premature labor and an updated meta-analysis.

RESULTS

The clinical trial was terminated early after 41 women were enrolled. Vaginal progesterone treatment did not change the median gestational age at delivery: 36+2 weeks versus 36+4 weeks, p = .865 nor increase the mean latency to delivery: 44.5 days versus 46.6 days, p = .841. In the updated meta-analysis, progesterone treatment did reduce delivery <37 weeks gestation and increase latency to delivery, but this treatment effect was not evident in the high quality trials: (OR 1.23, 95% CI 0.91, 1.67) and (-0.95 days, 95% CI -5.54, 3.64) respectively.

CONCLUSION

Progesterone is not effective for preventing preterm birth following arrested preterm labor.

Diversity of progesterone action on lipopolysaccharide-induced expression changes in cultured human cervical fibroblasts according to inflammation and treatment timing

PROBLEM

The effectiveness of progesterone (P4) treatment for preventing preterm births is unclear. Its effects on the uterine cervix were tested using cultured human uterine cervical fibroblasts (UCFs).

METHOD OF STUDY

UCFs were incubated with lipopolysaccharide (LPS) in the presence or absence of P4 under various conditions. mRNA was subjected to PCR arrays and real-time RT-PCR to assess IL-6, IL-8, IL-1beta, PTGS2, MMP-1, and CXCL10 expression.

RESULTS

When exposed to a high-LPS concentration (2.0 μg/mL), expression of these genes was not suppressed by simultaneous P4 (1.0 μmol/L) treatment, but it was significantly inhibited when P4 was administered 1 hour prior to LPS, with the exception of the chemokines IL-8 and CXCL10. Expression of all genes was restricted by P4 under low-level LPS (0.2 μg/mL) stimulation, especially when administered prior to LPS treatment.

CONCLUSION

These data suggest that early or prophylactic P4 administration is an effective and important measure for reducing preterm birth risk.

Cervical Pessary for Preventing Preterm Birth in Singleton Pregnancies With Short Cervical Length: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the effectiveness of cervical pessary for preventing spontaneous preterm birth (SPTB) in singleton gestations with a second trimester short cervix.

METHODS

Electronic databases were searched from their inception until February 2016. We included randomized clinical trials (RCTs) comparing the use of the cervical pessary with expectant management in singletons pregnancies with transvaginal ultrasound cervical length (TVU CL) ≤25 mm. The primary outcome was incidence of SPTB <34 weeks. The summary measures were reported as relative risk (RR) with 95% confidence interval (CI).

RESULTS

Three RCTs (n = 1,420) were included. The mean gestational age (GA) at randomization was approximately 22 weeks. The Arabin pessary was used as intervention in all three trials, and was removed by vaginal examination at approximately 37 weeks. Cervical pessary was not associated with prevention of SPTB <37 (20.2% vs 50.2%; RR 0.50, 95% CI 0.23 to 1.09), <34, <32, and <28 weeks, compared to no pessary. No differences were found in the mean of GA at, interval from randomization to delivery, incidence of preterm premature rupture of membranes and of cesarean delivery, and in neonatal outcomes. The Arabin pessary was associated with a significantly higher risk of vaginal discharge.

CONCLUSIONS

In singleton pregnancies with a TVU CL ≤25mm at 20⁰ -24⁶ weeks, the Arabin pessary does not reduce the rate of spontaneous preterm delivery or improve perinatal outcome. Individual patient data meta-analysis may clarify whether cervical pessary may be beneficial in subgroups, such as only singleton gestations without prior SPTB or by different CL cutoffs.

Variation in Coverage for Progesterone to Prevent Preterm Birth: A Survey of Medicaid Managed Care Organizations

INTRODUCTION

Preterm birth is the leading cause of U.S. infant morbidity and mortality; Medicaid enrollees disproportionately experience preterm deliveries. Data suggest that progesterone-an evidence-based therapy for preventing preterm birth-is not accessible to all eligible Medicaid beneficiaries. This study aimed to identify variation in progesterone coverage guidelines in a sample of state Medicaid managed care organizations (MMCOs).

MATERIAL AND METHODS

Using a cross-sectional design, participation in a web-based survey was offered to 20 MMCO members of the Medicaid Health Plans of America. The survey assessed coverage guidelines for progesterone and associated interventions to prevent preterm birth. MMCOs identified key barriers in providing progesterone. Descriptive analyses were performed.

RESULTS

Analyses included data from 18 plans providing coverage in 31 of the 39 states with MMCOs (response rate, 90.0%). Responding MMCOs were diverse: 55.6% were multistate, 33.3% were nonprofit, and 31.2% covered more than 1,000,000 lives. Most respondents (87.5%) covered branded progesterone, and 81.3% covered compounded progesterone. Prior authorization was required by most plans for branded progesterone (86.7%) or compounded progesterone (75.0%). The MMCO gestational age restrictions for initiating progesterone varied from 22 to 37 weeks of gestation, even within the same state. MMCO-identified barriers to providing progesterone included cost, lack of clinician knowledge of indications and coverage, and variation in billing procedures.

DISCUSSION

Marked variation in MMCO coverage policies and procedures for progesterone and related interventions to prevent preterm birth was noted.

IMPLICATIONS FOR PRACTICE AND POLICY

Standardizing MMCO coverage policies may be one way to improve access to evidence-based interventions that prevent preterm birth.

Assessment of Transvaginal Ultrasound Cervical Length Image Quality

OBJECTIVE

To use data from the Cervical Length Education and Review program to evaluate the quality of transvaginal cervical length ultrasonography by trained imagers (ie, ultrasonographers, radiologists, perinatologists).

METHODS

This is a retrospective observational study of data from the Cervical Length Education and Review program. Candidates underwent an online lecture series, examination, and submitted a batch of images for review. For a candidate's batch of images to pass, all images must meet at least seven of the nine criteria assessed, the overall batch score needs to be 80% or greater, correct caliper placement must be met for all images, and the same criterion cannot be consistently missed. We also examined a subset of these criteria-appropriate image acquisitions, defined as an image that demonstrated both internal and external os and visualization of the entire endocervical canal. Primary outcome was the overall initial candidate pass rate; secondary outcomes included distribution of criteria missed in images and percentage of images that was inadequately acquired.

RESULTS

Six hundred eighty-seven candidates submitted 3,748 images between June 10, 2012, and August 18, 2016. Eighty-five percent of candidates were ultrasonographers. Of the 687 initial batches submitted, 105 (15%) did not pass. Eight hundred thirty-seven images (22%) of all images failed at least one criterion; the most common image deficiencies were in "anterior width of cervix equals the posterior width" (33%), "failure to visualize" the internal or external os (29%), "cervix occupies 75% of image and bladder area visible" (33%), and incorrect caliper placement (24%). Two hundred fifty-six (7%) of all images failed to meet our criteria for adequate image acquisition.

CONCLUSION

Fifteen percent of trained imagers failed to obtain appropriate cervical length imaging. This highlights the importance of a standardized cervical length training and certification program.

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.

17-alpha Hydroxyprogesterone caproate did not reduce the rate of recurrent preterm birth in a prospective cohort study

BACKGROUND

17-alpha Hydroxyprogesterone caproate for prevention of recurrent preterm birth is recommended for use in the United States.

OBJECTIVE

We sought to assess the clinical effectiveness of 17-alpha hydroxyprogesterone caproate to prevent recurrent preterm birth ≤35 weeks compared to similar births in our obstetric population prior to the implementation of 17-alpha hydroxyprogesterone caproate.

STUDY DESIGN

This was a prospective cohort study of 17-alpha hydroxyprogesterone caproate in our obstetric population. The primary outcome was the recurrence of birth ≤35 weeks for the entire study cohort compared to a historical referent rate of 16.8% of recurrent preterm birth in our population. There were 3 secondary outcomes. First, did 17-alpha hydroxyprogesterone caproate modify a woman's history of preterm birth when taking into account her prior number and sequence of preterm and term births? Second, was recurrence of preterm birth related to 17-alpha hydroxyprogesterone caproate plasma concentration? Third, was duration of pregnancy modified by 17-alpha hydroxyprogesterone caproate treatment compared to a prior preterm birth?

RESULTS

From January 2012 through March 2016, 430 consecutive women with prior births ≤35 weeks were treated with 17-alpha hydroxyprogesterone caproate. Nearly two thirds of the women (N = 267) began injections ≤18 weeks and 394 (92%) received a scheduled weekly injection within 10 days of reaching 35 weeks or delivery. The overall rate of recurrent preterm birth was 25% (N = 106) for the entire cohort compared to the 16.8% expected rate (P = 1.0). The 3 secondary outcomes were also negative. First, 17-alpha hydroxyprogesterone caproate did not significantly reduce the rates of recurrence regardless of prior preterm birth number or sequence. Second, plasma concentrations of 17-alpha hydroxyprogesterone caproate were not different (P = .17 at 24 weeks; P = .38 at 32 weeks) between women delivered ≤35 weeks and those delivered later in pregnancy. Third, the mean (±SD) interval in weeks of recurrent preterm birth before 17-alpha hydroxyprogesterone caproate use was 0.4 ± 5.3 weeks and the interval of recurrent preterm birth after 17-alpha hydroxyprogesterone caproate treatment was 0.1 ± 4.7 weeks (P = .63). A side effect of weekly 17-alpha hydroxyprogesterone caproate injections was an increase in gestational diabetes. Specifically, the rate of gestational diabetes was 13.4% in 17-alpha hydroxyprogesterone caproate-treated women compared to 8% in case-matched controls (P = .001).

CONCLUSION

17-alpha Hydroxyprogesterone caproate was ineffective for prevention of recurrent preterm birth and was associated with an increased rate of gestational diabetes.

Reducing preterm birth by a statewide multifaceted program: an implementation study

BACKGROUND

A comprehensive preterm birth prevention program was introduced in the state of Western Australia encompassing new clinical guidelines, an outreach program for health care practitioners, a public health program for women and their families based on print and social media, and a new clinic at the state's sole tertiary level perinatal center for referral of those pregnant women at highest risk. The initiative had the single aim of safely lowering the rate of preterm birth.

OBJECTIVE

The objective of the study was to evaluate the outcomes of the initiative on the rates of preterm birth both statewide and in the single tertiary level perinatal referral center.

STUDY DESIGN

This was a prospective population-based cohort study of perinatal outcomes before and after 1 full year of implementation of the preterm birth prevention program.

RESULTS

In the state overall, the rate of singleton preterm birth was reduced by 7.6% and was lower than in any of the preceding 6 years. This reduction amounted to 196 cases relative to the year before the introduction of the initiative and the effect extended from the 28-31 week gestational age group onward. Within the tertiary level center, the rate of preterm birth in 2015 was also significantly lower than in the preceding years.

CONCLUSION

A comprehensive and multifaceted preterm birth prevention program aimed at both health care practitioners and the general public, operating within the environment of a government-funded universal health care system can significantly lower the rate of early birth. Further research is now required to increase the effect and to determine the relative contributions of each of the interventions.

Prevention of preterm birth with pessary in twins (PoPPT): a randomized controlled trial

OBJECTIVE

To evaluate whether cervical pessary placement prevents preterm birth (PTB) in twin gestations with a short mid-trimester cervical length (CL) on transvaginal sonography (TVS).

METHODS

This was a multicenter randomized controlled trial of asymptomatic women with a twin gestation and a TVS-CL of ≤ 30 mm at 18 + 0 to 27 + 6 weeks' gestation. TVS-CL was measured at the time of the fetal anatomy scan at 18 + 0 to 23 + 6 weeks and at subsequent scheduled ultrasound scans prior to 28 weeks. Women with a TVS-CL of ≤ 30 mm at 18 + 0 to 27 + 6 weeks were randomized to receive either the Bioteque™ cup cervical pessary or no pessary. Randomization was stratified by gestational age, study site and chorionicity. Women with a monoamniotic twin gestation, twin-twin transfusion syndrome, early selective intrauterine growth restriction or placenta previa were excluded. Cervical pessaries were inserted by maternal-fetal medicine staff centrally trained in proper placement. No other treatment for women with a short cervix was recommended. Primary outcome was PTB < 34 weeks. The trial was stopped early before complete enrollment.

RESULTS

A total of 421 women with a twin gestation were screened for TVS-CL, and 85 (20%) had a TVS-CL of ≤ 30 mm. Of these, 80 (94%) met the eligibility criteria and 46 (58%) of the eligible women agreed to randomization. Twenty-three (50%) women were randomized to pessary placement and 23 (50%) to no pessary. Demographic characteristics, including median gestational age (21.0 vs 21.2 weeks; P = 0.69) and TVS-CL (16.7 vs 22.9 mm; P = 0.45) at randomization, were similar between the pessary and no-pessary groups, except for level of education (more than high school education: 48% vs 78%, respectively; P = 0.03) and proportion of spontaneous conceptions (83% vs 43%, respectively; P = 0.01). There were no significant differences between the pessary and no-pessary groups in rate of primary outcome, PTB < 34 weeks (39% vs 35%; relative risk, 1.13 (95% CI, 0.53-2.40)), as well as other outcomes, including PTB < 37 weeks and < 28 weeks, gestational age at delivery, birth weight and composite adverse neonatal outcome.

CONCLUSION

Treatment with cervical pessary was not associated with the prevention of PTB in women with a twin gestation and a mid-trimester TVS-CL of ≤ 30 mm in this small underpowered randomized controlled trial. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

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.

Progesterone in normal and pathological pregnancy

Progesterone is an essential hormone in the process of reproduction. It is involved in the menstrual cycle, implantation and is essential for pregnancy maintenance. It has been proposed and extensively used in the treatment of different gynecological pathologies as well as in assisted reproductive technologies and in the maintenance of pregnancy. Called "the pregnancy hormone", natural progesterone is essential before pregnancy and has a crucial role in its maintenance based on different mechanisms such as: modulation of maternal immune response and suppression of inflammatory response (the presence of progesterone and its interaction with progesterone receptors at the decidua level appears to play a major role in the maternal defense strategy), reduction of uterine contractility (adequate progesterone concentrations in myometrium are able to counteract prostaglandin stimulatory activity as well as oxytocin), improvement of utero-placental circulation and luteal phase support (it has been demonstrated that progesterone may promote the invasion of extravillous trophoblasts to the decidua by inhibiting apoptosis of extravillous trophoblasts). Once the therapeutic need of progesterone is established, the key factor is the decision of the best route to administer the hormone and the optimal dosage determination. Progesterone can be administered by many different routes, but the most utilized are oral, the vaginal and intramuscular administration. The main uses of progesterone are represented by: threatened miscarriage, recurrent miscarriage and preterm birth (in the prevention strategy, as a tocolytic agent and also in the maintenance of uterine quiescence).

Present and future aspects of dydrogesterone in prevention or treatment of pregnancy disorders: an outlook

Over time, it became evident that with the use of micronized progesterone and dydrogesterone prevention or treatment of pregnancy disorders such as threatened miscarriage, recurrent (habitual) miscarriage, preterm labor or preeclampsia appears to be possible. The results so far obtained will be delineated and concepts of prevention or treatment are suggested with the aim to further explore these pregnancy disorders either by prevention or treatment concepts to obtain not only benefits to the mother and the fetus, but furthermore this results in benefits for lifetime for the individual, for the family and last but not least for society.

Vaginal progesterone decreases preterm birth and neonatal morbidity and mortality in women with a twin gestation and a short cervix: an updated meta-analysis of individual patient data

OBJECTIVE

To assess the efficacy of vaginal progesterone for the prevention of preterm birth and neonatal morbidity and mortality in asymptomatic women with a twin gestation and a sonographic short cervix (cervical length ≤ 25 mm) in the mid-trimester.

METHODS

This was an updated systematic review and meta-analysis of individual patient data (IPD) from randomized controlled trials comparing vaginal progesterone with placebo/no treatment in women with a twin gestation and a mid-trimester sonographic cervical length ≤ 25 mm. MEDLINE, EMBASE, POPLINE, CINAHL and LILACS (all from inception to 31 December 2016), the Cochrane Central Register of Controlled Trials, Research Registers of ongoing trials, Google Scholar, conference proceedings and reference lists of identified studies were searched. The primary outcome measure was preterm birth < 33 weeks' gestation. Two reviewers independently selected studies, assessed the risk of bias and extracted the data. Pooled relative risks (RRs) with 95% confidence intervals (CI) were calculated.

RESULTS

IPD were available for 303 women (159 assigned to vaginal progesterone and 144 assigned to placebo/no treatment) and their 606 fetuses/infants from six randomized controlled trials. One study, which included women with a cervical length between 20 and 25 mm, provided 74% of the total sample size of the IPD meta-analysis. Vaginal progesterone, compared with placebo/no treatment, was associated with a statistically significant reduction in the risk of preterm birth < 33 weeks' gestation (31.4% vs 43.1%; RR, 0.69 (95% CI, 0.51-0.93); moderate-quality evidence). Moreover, vaginal progesterone administration was associated with a significant decrease in the risk of preterm birth < 35, < 34, < 32 and < 30 weeks' gestation (RRs ranging from 0.47 to 0.83), neonatal death (RR, 0.53 (95% CI, 0.35-0.81)), respiratory distress syndrome (RR, 0.70 (95% CI, 0.56-0.89)), composite neonatal morbidity and mortality (RR, 0.61 (95% CI, 0.34-0.98)), use of mechanical ventilation (RR, 0.54 (95% CI, 0.36-0.81)) and birth weight < 1500 g (RR, 0.53 (95% CI, 0.35-0.80)) (all moderate-quality evidence). There were no significant differences in neurodevelopmental outcomes at 4-5 years of age between the vaginal progesterone and placebo groups.

CONCLUSION

Administration of vaginal progesterone to asymptomatic women with a twin gestation and a sonographic short cervix in the mid-trimester reduces the risk of preterm birth occurring at < 30 to < 35 gestational weeks, neonatal mortality and some measures of neonatal morbidity, without any demonstrable deleterious effects on childhood neurodevelopment. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Recurrence of second trimester miscarriage and extreme preterm delivery at 16-27 weeks of gestation with a focus on cervical insufficiency and prophylactic cerclage

INTRODUCTION

The objective of this study was to describe recurrence rates of second trimester miscarriage and extreme preterm delivery by phenotype and use of prophylactic cerclage in a register-based cohort.

MATERIAL AND METHODS

We included women with a first second trimester miscarriage or extreme preterm delivery (16⁺⁰ to 27⁺⁶ gestational weeks) in Denmark in 1997-2012 (n = 9602) by combined use of the Danish Medical Birth Register and the Danish National Patient Register. Eight phenotypes were identified by ICD-10 codes in a hierarchy with the following sequence: major fetal anomaly, multiple gestation, uterine anomaly, placental insufficiency, antepartum bleeding, cervical insufficiency, preterm premature rupture of membranes, and intrauterine fetal death. Recurrence rate after a second trimester miscarriage/spontaneous delivery in the period was calculated based on the register data. In cervical insufficiency outcome was stratified by prophylactic cerclage applied <16 weeks of gestation.

RESULTS

Overall recurrence rate was 7.3% (n = 452), a rate that differed by phenotype from <5% (fetal anomaly, multiple gestations, intrauterine fetal death) to 21% (cervical insufficiency). In women with cervical insufficiency the recurrence rate was 28% without cerclage; vaginal cerclage was associated with a significant reduction [adjusted odds ratio (OR) 0.47; 95% CI 0.29-0.76] and abdominal cerclage with an even greater reduction (adjusted OR 0.14; 95% CI 0.03-0.61).

CONCLUSIONS

The overall recurrence rate of second trimester miscarriage or extreme preterm delivery was 7%, but it differed significantly by phenotype. The highest rate, 28%, was found in cervical insufficiency, and prophylactic cerclage was associated with a significant reduction in recurrence.

Association between change in cervical length and spontaneous preterm birth in twin pregnancies

BACKGROUND

There is a lack of consensus on the optimal transvaginal cervical length for determining risk for spontaneous preterm birth in twin pregnancies. Change in transvaginal cervical length over time may reflect early activation of the parturition process, as has been demonstrated in singleton pregnancies. The association between change in transvaginal cervical length and the risk for spontaneous preterm birth has not yet been described in the population of women with diamniotic twin pregnancies.

OBJECTIVE

Our primary objective is to determine whether rate of change in transvaginal cervical length in the midtrimester is associated with spontaneous preterm birth in twin gestations. Our secondary objective is to describe parameters for identifying patients at increased risk for spontaneous preterm birth based on change in transvaginal cervical length over time.

STUDY DESIGN

This is a retrospective cohort of serial transvaginal cervical length performed for twin pregnancies at a single institution from 2008 through 2015. Women with diamniotic twin pregnancies who had transvaginal cervical length measurements at 18 and 22 weeks' gestation and outcome data available were included. Logistic regression was used to determine the relationship between the rate of change in transvaginal cervical length and the risk for the primary outcome of spontaneous preterm birth <35 weeks as well as spontaneous preterm birth <32 weeks.

RESULTS

In all, 527 subjects met inclusion criteria for this study. The average rate of change in transvaginal cervical length for patients with spontaneous preterm birth <35 weeks was -0.21 cm/wk (SD 0.27) vs -0.10 cm/wk (SD 0.24) for patients who delivered ≥35 weeks (P < .01). The rate of change in transvaginal cervical length was associated with spontaneous preterm birth <35 weeks when controlling for initial transvaginal cervical length and other important risk factors for spontaneous preterm birth. Results for spontaneous preterm birth <32 weeks were similar. This association remained significant when the rate of weekly change was treated as a dichotomous variable based on an apparent inflection point in the risk for spontaneous preterm birth: women with rapid change in transvaginal cervical length, ≥-0.2 cm/wk, had 3.45 times the odds of spontaneous preterm birth as those with less rapid change (95% confidence interval, 2.15-5.52) when controlling for initial transvaginal cervical length.

CONCLUSION

Change in transvaginal cervical length in the midtrimester is associated with spontaneous preterm birth, and therefore protocols for serial transvaginal cervical length measurement can provide the clinician with information to identify at-risk patients. A decrease of ≥0.2 cm/wk of transvaginal cervical length identifies patients at increased risk for spontaneous preterm birth <35 weeks.

Pregnant women's preferences for and concerns about preterm birth prevention: a cross-sectional survey

BACKGROUND

Although there is a call for patient-centred prenatal care, women's preferences for and concerns about preterm birth (PTB) prevention have not been well-studied. Therefore, we conducted a cross-sectional survey to determine women's preferences for PTB prevention and their likelihood of following their healthcare provider's recommendations for PTB prevention, as well as factors associated with these responses.

METHODS

A piloted self-administered questionnaire was completed by pregnant women who could read English. Data were collected about their preferences for and concerns about PTB prevention, and the likelihood of following their healthcare provider's recommendations, using multivariable logistic regression to control for other factors.

RESULTS

Three hundred and eleven women at a median of 32-weeks of gestation completed the survey, a response rate of 85.2%. Most women reported that if they were told they were at increased risk for PTB, they preferred not to use PTB prevention (65.8%), of whom almost all (93.4%) reported they preferred close-monitoring and 6.6% preferred neither monitoring nor prevention. A much smaller proportion of women reported that they would not follow their healthcare provider's recommendation for progesterone (10.9%) compared to pessary (28.7%) or cerclage (50.2%). Women who were neither married nor in a common-law relationship were more likely to report that they would not follow recommendations for progesterone (aOR = 5.88 [95% CI: 1.72, 20.00]). Most women (84.5%) reported they would use other sources of information other than their main healthcare provider to learn more about PTB prevention, with the most popular source being the internet.

CONCLUSIONS

Most women reported that if they were told they were at increased risk of PTB, they preferred close-monitoring over using PTB prevention. Their reported likelihood of not following their healthcare provider's recommendations for PTB prevention varied from 10.9% for progesterone to 50.2% for cerclage. These findings suggest that more education about the risk of PTB, PTB preventions, as well as compliance with progesterone is needed and that the internet would be an important source of information. However as our study was completed by women at a median of 32 weeks of gestation, future surveys targeted at women earlier in their pregnancy are needed.

The interaction between vaginal microbiota, cervical length, and vaginal progesterone treatment for preterm birth risk

BACKGROUND

Preterm birth is the primary cause of infant death worldwide. A short cervix in the second trimester of pregnancy is a risk factor for preterm birth. In specific patient cohorts, vaginal progesterone reduces this risk. Using 16S rRNA gene sequencing, we undertook a prospective study in women at risk of preterm birth (n = 161) to assess (1) the relationship between vaginal microbiota and cervical length in the second trimester and preterm birth risk and (2) the impact of vaginal progesterone on vaginal bacterial communities in women with a short cervix.

RESULTS

Lactobacillus iners dominance at 16 weeks of gestation was significantly associated with both a short cervix <25 mm (n = 15, P < 0.05) and preterm birth <34⁺⁰ weeks (n = 18; P < 0.01; 69% PPV). In contrast, Lactobacillus crispatus dominance was highly predictive of term birth (n = 127, 98% PPV). Cervical shortening and preterm birth were not associated with vaginal dysbiosis. A longitudinal characterization of vaginal microbiota (<18, 22, 28, and 34 weeks) was then undertaken in women receiving vaginal progesterone (400 mg/OD, n = 25) versus controls (n = 42). Progesterone did not alter vaginal bacterial community structure nor reduce L. iners-associated preterm birth (<34 weeks).

CONCLUSIONS

L. iners dominance of the vaginal microbiota at 16 weeks of gestation is a risk factor for preterm birth, whereas L. crispatus dominance is protective against preterm birth. Vaginal progesterone does not appear to impact the pregnancy vaginal microbiota. Patients and clinicians who may be concerned about "infection risk" associated with the use of a vaginal pessary during high-risk pregnancy can be reassured.

Early midtrimester serum insulin-like factors and cervical length to predict preterm delivery

OBJECTIVE

To investigate which ultrasound findings or serum biomarkers, including insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 and 3 (IGFBP-1 and IGFBP-3, respectively), in the first and early second trimesters are the best predictors for preterm delivery.

MATERIALS AND METHODS

This was a case-control study conducted between March 2011 and March 2013 with women presenting for routine antenatal care at 11-18 weeks. We collected serum samples from pregnant women and stored them at -80°C. All patients underwent cervical length (CL) measurement at 18-21 weeks. We retrieved frozen samples for analysis from women with subsequent preterm and term delivery. Prediction models were developed using multivariate stepwise logistic regression. Receiver-operating characteristics curves were used to determine the most useful cutoff point.

RESULTS

Of the 72 women recruited, 24 women underwent spontaneous preterm delivery, and 48 women with term delivery were randomly selected as the control group, in a 1:2 ratio. The maternal serum concentration of IGFBP-3 and CL were significantly associated with preterm birth.

CONCLUSION

Among the various known ultrasound findings and serum biomarkers in the early midtrimester, only CL and IGFBP-3 are independent predictors for preterm delivery in asymptomatic women.