Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial

Progestin therapy to prevent preterm birth: History and effectiveness of current strategies and development of novel approaches

In the 1930s the "progestin" hormone produced by the corpus luteum was isolated and found to be a Δ4-keto-steroid. It was aptly named progesterone (P4) and in the following 30 years the capacity of P4 and derivatives to prevent preterm birth (PTB) was examined. Outcomes of multiple small studies suggested that progestin prophylaxis beginning at mid-gestation decreases the risk for PTB. Subsequent larger trials found that prophylaxis with weekly intramuscular injections of 17α-hydroxyprogesterone caproate (17HPC) beginning at mid-gestation decreased PTB risk in women with a history of PTB. Other trials found that daily vaginal P4 prophylaxis, also beginning at mid-gestation decreased PTB risk in women with a short cervix. Currently, prophylaxis with 17HPC (in women with a history of PTB) or vaginal P4 (in women with a short cervix) are used to prevent PTB. Recent advances in understanding the molecular biology of P4 signaling in uterine cells is revealing novel progestin-based targets for PTB prevention. One possibility is to use selective P4 receptor (PR) modulators (SPRMs) to boost PR anti-inflammatory activity that blocks labor, while simultaneously preventing PR phosphorylation that causes loss of P4/PR anti-inflammatory activity. This may be achieved by SPRMs that induce a specific PR conformation that prevents site-specific serine phosphorylation that inhibits anti-inflammatory activity. Further advances in understanding how P4 promotes uterine quiescence and how its labor blocking actions are withdrawn to trigger parturition will reveal novel therapeutic targets to more effectively prevent PTB.

Vaginal progesterone, oral progesterone, 17-OHPC, cerclage, and pessary for preventing preterm birth in at-risk singleton pregnancies: an updated systematic review and network meta-analysis

BACKGROUND

Recent progesterone trials call for an update of previous syntheses of interventions to prevent preterm birth.

OBJECTIVES

To compare the relative effects of different types and routes of administration of progesterone, cerclage, and pessary at preventing preterm birth in at-risk women overall and in specific populations.

SEARCH STRATEGY

We searched Medline, EMBASE, CINAHL, Cochrane CENTRAL, and Web of Science up to 1 January 2018.

SELECTION CRITERIA

We included randomised trials of progesterone, cerclage or pessary for preventing preterm birth in at-risk singleton pregnancies.

DATA COLLECTION AND ANALYSIS

We used a piloted data extraction form and performed Bayesian random-effects network meta-analyses with 95% credibility intervals (CrI), as well as pairwise meta-analyses, rating the quality of the evidence using GRADE.

MAIN RESULTS

We included 40 trials (11 311 women). In at-risk women overall, vaginal progesterone reduced preterm birth <34 (OR 0.43, 95% CrI 0.20-0.81) and <37 weeks (OR 0.51, 95% CrI 0.34-0.74), and neonatal death (OR 0.41, 95% CrI 0.20-0.83). In women with a previous preterm birth, vaginal progesterone reduced preterm birth <34 (OR 0.29, 95% CI 0.12-0.68) and <37 weeks (OR 0.43, 95% CrI 0.23-0.74), and 17α-hydroxyprogesterone caproate reduced preterm birth <37 weeks (OR 0.53, 95% CrI 0.27-0.95) and neonatal death (OR 0.39, 95% CI 0.16-0.95). In women with a short cervix (≤25 mm), vaginal progesterone reduced preterm birth <34 weeks (OR 0.45, 95% CI 0.24-0.84).

CONCLUSIONS

Vaginal progesterone was the only intervention with consistent effectiveness for preventing preterm birth in singleton at-risk pregnancies overall and in those with a previous preterm birth.

TWEETABLE ABSTRACT

In updated NMA, vaginal progesterone consistently reduced PTB in overall at-risk pregnancies and in women with previous PTB.

Progesterone-Related Immune Modulation of Pregnancy and Labor

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

Effector and Activated T Cells Induce Preterm Labor and Birth That Is Prevented by Treatment with Progesterone

Preterm labor commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. Most research has focused on establishing a causal link between innate immune activation and pathological inflammation leading to preterm labor and birth. However, the role of maternal effector/activated T cells in the pathogenesis of preterm labor/birth is poorly understood. In this study, we first demonstrated that effector memory and activated maternal T cells expressing granzyme B and perforin are enriched at the maternal-fetal interface (decidua) of women with spontaneous preterm labor. Next, using a murine model, we reported that prior to inducing preterm birth, in vivo T cell activation caused maternal hypothermia, bradycardia, systemic inflammation, cervical dilation, intra-amniotic inflammation, and fetal growth restriction, all of which are clinical signs associated with preterm labor. In vivo T cell activation also induced B cell cytokine responses, a proinflammatory macrophage polarization, and other inflammatory responses at the maternal-fetal interface and myometrium in the absence of an increased influx of neutrophils. Finally, we showed that treatment with progesterone can serve as a strategy to prevent preterm labor/birth and adverse neonatal outcomes by attenuating the proinflammatory responses at the maternal-fetal interface and cervix induced by T cell activation. Collectively, these findings provide mechanistic evidence showing that effector and activated T cells cause pathological inflammation at the maternal-fetal interface, in the mother, and in the fetus, inducing preterm labor and birth and adverse neonatal outcomes. Such adverse effects can be prevented by treatment with progesterone, a clinically approved strategy.

Metabolomics applied to maternal and perinatal health: a review of new frontiers with a translation potential

The prediction or early diagnosis of maternal complications is challenging mostly because the main conditions, such as preeclampsia, preterm birth, fetal growth restriction, and gestational diabetes mellitus, are complex syndromes with multiple underlying mechanisms related to their occurrence. Limited advances in maternal and perinatal health in recent decades with respect to preventing these disorders have led to new approaches, and "omics" sciences have emerged as a potential field to be explored. Metabolomics is the study of a set of metabolites in a given sample and can represent the metabolic functioning of a cell, tissue or organism. Metabolomics has some advantages over genomics, transcriptomics, and proteomics, as metabolites are the final result of the interactions of genes, RNAs and proteins. Considering the recent "boom" in metabolomic studies and their importance in the research agenda, we here review the topic, explaining the rationale and theory of the metabolomic approach in different areas of maternal and perinatal health research for clinical practitioners. We also demonstrate the main exploratory studies of these maternal complications, commenting on their promising findings. The potential translational application of metabolomic studies, especially for the identification of predictive biomarkers, is supported by the current findings, although they require external validation in larger datasets and with alternative methodologies.

Cervicovaginal microbiota and local immune response modulate the risk of spontaneous preterm delivery

Failure to predict and understand the causes of preterm birth, the leading cause of neonatal morbidity and mortality, have limited effective interventions and therapeutics. From a cohort of 2000 pregnant women, we performed a nested case control study on 107 well-phenotyped cases of spontaneous preterm birth (sPTB) and 432 women delivering at term. Using innovative Bayesian modeling of cervicovaginal microbiota, seven bacterial taxa were significantly associated with increased risk of sPTB, with a stronger effect in African American women. However, higher vaginal levels of β-defensin-2 lowered the risk of sPTB associated with cervicovaginal microbiota in an ethnicity-dependent manner. Surprisingly, even in Lactobacillus spp. dominated cervicovaginal microbiota, low β-defensin-2 was associated with increased risk of sPTB. These findings hold promise for diagnostics to accurately identify women at risk for sPTB early in pregnancy. Therapeutic strategies could include immune modulators and microbiome-based therapeutics to reduce this significant health burden.

Addition of Cervical Elastography May Increase Preterm Delivery Prediction Performance in Pregnant Women with Short Cervix: a Prospective Study

BACKGROUND

We investigated whether there is a difference in elastographic parameters between pregnancies with and without spontaneous preterm delivery (sPTD) in women with a short cervix (≤ 25 mm), and examined the ability of elastographic parameters to predict sPTD in those women.

METHODS

E-Cervix^TM (WS80A; Samsung Medison, Seoul, Korea) elastography was used to examine the cervical strain. Elastographic parameters were compared between pregnancies with and without sPTD. Diagnostic performance of elastographic parameters to predict sPTD ≤ 37 weeks, both alone and in combination with other parameters, was compared with that of cervical length (CL) using area under receiver operating characteristic curve (AUC) analysis.

RESULTS

A total of 130 women were included. Median gestational age (GA) at examination was 24.4 weeks (interquartile range, 21.4-28.9), and the prevalence of sPTD was 20.0% (26/130). Both the elastographic parameters and CL did not show statistical difference between those with and without sPTD. However, when only patients with CL ≥ 1.5 cm (n = 110) were included in the analysis, there was a significant difference between two groups in elasticity contrast index (ECI) within 0.5/1.0/1.5 cm from the cervical canal (P < 0.05) which is one of elastographic parameters generated by E-Cervix. When AUC analysis was performed in women with CL ≥ 1.5 cm, the combination of parameters (CL + pre-pregnancy body mass index + GA at exam + ECI within 0.5/1.0/1.5 cm) showed a significantly higher AUC than CL alone (P < 0.05).

CONCLUSION

An addition of cervical elastography may improve the ability to predict sPTD in women with a short CL between 1.5 and 2.5 cm.

Universal cervical length screening with a cervicometer to prevent preterm birth <34 weeks: a decision and economic analysis

Background: Preterm birth is a leading cause of neonatal morbidity and mortality worldwide; evidence-based strategies to decrease preterm birth are desperately needed.Objective: The purpose of this study was to estimate which of three strategies for screening for shortened cervix in asymptomatic low-risk women is the most cost-effective in terms of prevention of preterm birth and associated morbidity.Study design: A decision analysis model was developed from available published evidence comparing three strategies in screening asymptomatic low-risk women for shortened cervix: (1) cervicometer with subsequent referral for transvaginal ultrasound, (2) transvaginal ultrasound screening, and (3) no screening. The cost and effectiveness of each strategy was assessed in terms of quality-adjusted life-years (QALYs), and cost in US dollars.Results: Screening with a cervicometer with referral was the most cost-effective strategy and represented a savings of $999.65 ($11,617.28 versus $12,616.93) over screening with ultrasound, and a savings of $15,601.62 ($11,617.28 versus $27,218.90) over no screening. Costs for outcomes ranged from $3528 for a healthy neonate ≥34 weeks to $717,467.5 for a neonate <34 weeks with severe morbidity. The cervicometer strategy avoided 11.68 neonatal deaths per 1000 deliveries (3.59 deaths versus 15.27 deaths) compared with no screening, and avoided 0.73 neonatal deaths per 1000 deliveries (3.59 deaths versus 4.32 deaths) compared with ultrasound strategy. The cervicometer strategy prevented 82.44 preterm births per 1000 deliveries (22.56 versus 105.00) compared with no screening, and 5.10 preterm births per 1000 deliveries (22.56 versus 27.66) compared with ultrasound strategy. Per QALY, cervicometer screening cost $386.57, transvaginal ultrasound cost $420.31, and no screening cost $922.73. Sensitivity analyses confirmed the robustness of these findings, including evaluation across the range of quoted transvaginal ultrasound costs ($43-$300).Conclusion: A simulation of universal screening of asymptomatic low-risk women with a cervicometer with subsequent referral for ultrasound for those with a cervix <25 mm is cost-effective and yields the greatest reduction in preterm births at <34 weeks. A risk simulation trial noted that a cervicometer strategy may be more expensive than a universal transvaginal ultrasound strategy, but both are less expensive than a no screening strategy.

Development of a mucoinert progesterone nanosuspension for safer and more effective prevention of preterm birth

Preterm birth (PTB) is a significant global problem, but few therapeutic options exist. Vaginal progesterone supplementation has been demonstrated to reduce PTB rates in women with a sonographic short cervix, yet there has been little investigation into the most effective dose or delivery form. Further, vaginal products like progesterone gel often contain excipients that cause local toxicity, irritation, and leakage. Here, we describe the development and characterization of a mucoinert vaginal progesterone nanosuspension formulation for improved drug delivery to the female reproductive tract. We compare the pharmacokinetics and pharmacodynamics to the clinical comparator progesterone gel in pregnant mice and demonstrate increased vaginal absorption and biodistribution via the uterine first-pass effect. Importantly, the unique plasma progesterone double peak observed in humans, reflecting recirculation from the uterus, was also observed in pregnant mice with vaginal dosing. We adapted a mouse model of progesterone withdrawal that was previously believed to be incompatible with testing the efficacy of exogenous progestins, and are first to demonstrate efficacy in preventing preterm birth with vaginal progesterone in this model. Further, improved vaginal progesterone delivery by the nanosuspension led to increased efficacy in PTB prevention. Additionally, we identified histological and transcriptional evidence of cervical and uterine toxicity with a single vaginal administration of the clinical gel that are absent after dosing with the mucoinert nanosuspension formulation. We demonstrate that a progesterone formulation that is designed for improved vaginal progesterone absorption and vaginal biocompatibility could be more effective for PTB prevention.

Arabin cervical pessary with vaginal progesterone versus vaginal progesterone for preventing preterm delivery

Purpose: To compare the rate of preterm delivery in pregnant women with a short cervical length managed with Arabin cervical pessary and vaginal progesterone versus vaginal progesterone alone.Methods: This was a retrospective cohort study of singletons pregnancies managed in two tertiary medical centers between September 2011 and May 2017. One center utilized the combined treatment of Arabin cervical pessary and vaginal progesterone (study group) and the second utilized vaginal progesterone approach (control group).Results: During the study period, a total of 202 pregnant women who underwent vaginal ultrasonography between 15 and 29 weeks gestation. They all had short cervical length (≤25 mm). Among them, 94 (46.5%) and 108 (53.5%) patients were in the study and control group, respectively. A significantly higher rate of patients in the study group had either a history of cervical incompetence (9.6 vs. 0.9%, respectively, p = 0.006) or cervical surgery (7.9 vs. 0%, respectively, p = .003). Despite having shorter cervical length at recruitment (14.3 ± 5.9 vs. 16.9 ± 5.7, respectively, p = .002) the rate of spontaneous delivery < 34-week gestation was lower in the study group (7.4 vs. 17.6%, respectively, p = .036) and they delivered 1-week later compared to the control group (37.2 ± 2.1 vs. 36.2 ± 3.7, respectively, p = 0.02).Conclusion: We found that for pregnant women with singletons and who had a short cervical length, the combined treatment of Arabin cervical pessary and vaginal progesterone had lower rate of preterm delivery < 34 weeks of gestation and prolonged gestation compared to those women who were treated with vaginal progesterone alone. Our preliminary findings warrant randomized control studies in order to further illuminate our results.

Effects of antibiotic therapy in women with the amniotic fluid "sludge" at 15-24 weeks of gestation on pregnancy outcomes

Objective: The aim of this prospective study was to assess the efficacy of antibiotic therapy for the prevention of adverse pregnancy outcomes in women with the amniotic fluid "sludge" at 15-24 weeks of gestation.Methods: 245 women underwent transvaginal ultrasound cervical length measurement at 15-24 weeks of pregnancy and 29 out of them with amniotic fluid "sludge" were included in the study. Eight women with the "sludge" had cervical length >25 mm (Group I), seven-an asymptomatic short cervix (Group IIa) and 14 women with a short cervix had symptoms like low abdominal pain, back pain, and menstrual-like cramps (Group IIb). All participants received intravenous, oral and/or vaginal antibiotic therapy. Participants in Group IIa were additionally given vaginal progesterone (VP), and in Group IIb-VP and indomethacin. Placentas from women with preterm birth (PTB) underwent histological examination.Results: The amniotic fluid "sludge" detected at an ultrasound scan between 15-24 weeks of gestation was associated with long-term maternal infections, histological chorioamnionitis, and was viewed as a marker of intra-amniotic infection. Absence of intravenous antibiotic therapy during midtrimester of pregnancy in these women was associated with neonatal infection with intrauterine onset in 61.1%, postpartum endometritis in 23.1%, and rate of PTB 46.2%. Intravenous antibiotic therapy eliminated sonographic presence of the sludge and resulted in prevented of neonatal and postpartum infections, prevented the risk of PTB in women with the cervical length >25 mm, in those with an asymptomatic short cervix receiving VP, and in 70% of symptomatic women with a short cervix, who received them in combination VP/indomethacin. For those women whose approach was not fully beneficial, it allowed to delay delivery in 11-17 weeks.Conclusions: Although we found that intravenous antibiotic therapy at 15-24 weeks of gestation in women with amniotic fluid "sludge" can protect from infection-related complications and demonstrated high beneficial effects of adding antibiotics to anti-inflammatory drug (indomethacin) and/or VP in women with a short cervix, further larger studies are needed.

A Quality Study to Explore Rationale for Pregnant Women to Decline Transvaginal Cervical Length Screening

OBJECTIVES

To identify patient rationale for pregnant women to decline transvaginal cervical length screening.

METHODS

Survey data from 511 women presenting for second-trimester anatomy and transvaginal cervical length sonography were collected during a 4-month period from September 2016 to January 2017. Each patient completed a medical questionnaire that includes demographic and obstetric history data and a survey to document their acceptance or declination of transvaginal cervical length screening.

RESULTS

Of the 511 women included in the study, 5.9% (n = 30) declined transvaginal cervical length screening. Demographic characteristics and risk factors for prematurity were similar between those who accepted and declined. The sonographer performing the study was significantly associated with declination of transvaginal cervical length screening (P < .001), with 4 of 13 sonographers accounting for 83.3% of all declinations. The most frequently reported reasons for declining the transvaginal cervical length screening were feeling that it was not needed (47%; n = 14) and not feeling prepared for the transvaginal sonography (27%; n = 8).

CONCLUSION

The findings of this study indicate that the sonographer performing transvaginal cervical length screening may be associated with declination. The most common reasons patients cited for declining included not feeling that the study was needed and not feeling prepared for the procedure. Increased sonographer education and sonographer use of a scripted approach when discussing the procedure with patients may improve patient acceptance.

Use of the Pessary in the Prevention of Preterm Delivery

OBJECTIVE

 The gestational complication most associated with perinatal mortality and morbidity is spontaneous preterm birth with gestational age < 37 weeks. Therefore, it is necessary to identify its risk factors and attempt its prevention. The benefits of the pessary in prematurity are under investigation. Our objective was to analyze the use of the pessary in the prevention of preterm births in published studies, and to compare its efficacy with other methods.

METHODS

 Randomized clinical trials published between 2010 and 2018 were selected from electronic databases. Studies on multiple gestations were excluded.

RESULTS

 Two studies were in favor of the pessary as a preventive method, one study was contrary to the method and another two showed no statistically significant difference. The meta-analysis showed no statistical difference with the use of a cervical pessary in the reduction of births < 37 (odds ratio [OR]: 0.63; confidence interval [95% CI]: 0.38-1.06) and < 34 weeks (OR: 0.74; 95% CI: 0.35-1.57) CONCLUSION:  The pooled data available to date seems to show a lack of efficacy of the cervical pessary in the prevention of preterm birth, although the heterogeneity of the studies made comparisons more difficult.

The influence of the introduction of national guidelines on preterm birth prevention practice: UK experience

Objective

To identify the current status of specialist preterm labour (PTL) clinics and identify changes in management trends over the last 5 years following release of the NICE preterm birth (PTB) guidance.

Design

Postal Survey of Clinical Practice.

Setting

UK.

Population

All consultant‐led obstetric units.

Methods

A questionnaire was sent by post to all 187 NHS consultant‐led obstetric units. Units with a specialist PTL clinic were asked to answer a further six questions defining their protocol for risk stratification and management.

Main outcome measures

Current practice in specialist PTL clinics. Changes in treatment trends over 5 years.

Results

Thirty‐three PTL prevention clinics were identified, with 73% running weekly. NHS staff (84%) have replaced university staff as the lead clinicians (from 69% in 2012 to 21% in 2017), suggesting this clinic has become increasingly integrated with standard care for women at the highest risk of PTB. There has been a large shift from nearly half of clinics offering cerclage as primary treatment for short cervix to offering more choice (30%) between at least two of cerclage, vaginal progesterone or pessary and combinations of primary treatments (18%), demonstrating more equipoise among clinicians regarding therapies for short cervix.

Conclusions

Over 5 years, there has been a 44% increase in the number of specialist PTL clinics in the UK. Although there is a better consensus over the target high‐risk population, there is increasing heterogeneity among first‐line treatments for short cervix.

Tweetable abstract

UK PTB prevention clinics have increased by 44% over 5 years, with increasing clinical equipoise to best Rx for short cervix.

UK PTB prevention clinics have increased by 44% over 5 years, with increasing clinical equipoise to best Rx for short cervix.

Cervical funneling or intra-amniotic debris and preterm birth in nulliparous women with midtrimester cervical length less than 30 mm

OBJECTIVE

To evaluate whether the presence of cervical funneling or intra-amniotic debris identified in the second trimester is associated with a higher rate of preterm birth (PTB) in asymptomatic nulliparous pregnant women with a midtrimester cervical length (CL) less than 30 mm (i.e. below the 10th percentile).

METHODS

This was a secondary cohort analysis of data from a multicenter trial in nulliparous women between 16 and 22 weeks' gestation with a singleton gestation and CL less than 30 mm on transvaginal ultrasound, randomized to treatment with either 17-alpha-hydroxyprogesterone caproate or placebo. Sonographers were centrally certified in CL measurement, as well as in identification of intra-amniotic debris and cervical funneling. Univariable and multivariable analysis was performed to assess the associations of cervical funneling and intra-amniotic debris with PTB.

RESULTS

Of the 657 women randomized, 112 (17%) had cervical funneling only, 33 (5%) had intra-amniotic debris only and 45 (7%) had both on second-trimester ultrasound. Women with either of these findings had a shorter median CL than those without (21.0 mm vs 26.4 mm; P < 0.001). PTB prior to 37 weeks was more likely in women with cervical funneling (37% vs 21%; odds ratio (OR), 2.2 (95% CI, 1.5-3.3)) or intra-amniotic debris (35% vs 23%; OR, 1.7 (95% CI, 1.1-2.9)). Results were similar for PTB before 34 and before 32 weeks' gestation. After multivariable adjustment that included CL, PTB < 34 and < 32 weeks continued to be associated with the presence of intra-amniotic debris (adjusted OR (aOR), 1.85 (95% CI, 1.00-3.44) and aOR, 2.78 (95% CI, 1.42-5.45), respectively), but not cervical funneling (aOR, 1.17 (95% CI, 0.63-2.17) and aOR, 1.45 (95% CI, 0.71-2.96), respectively).

CONCLUSIONS

Among asymptomatic nulliparous women with midtrimester CL less than 30 mm, the presence of intra-amniotic debris, but not cervical funneling, is associated with an increased risk for PTB before 34 and 32 weeks' gestation, independently of CL. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Progestins Inhibit Tumor Necrosis Factor α-Induced Matrix Metalloproteinase 9 Activity via the Glucocorticoid Receptor in Primary Amnion Epithelial Cells

Progestins have been recommended for preterm birth prevention in high-risk women; however, their mechanism of action still remains an area of debate. Medroxyprogesterone acetate (MPA) has previously been shown to significantly inhibit tumor necrosis factor α (TNFα)-induced matrix metalloproteinase 9 (MMP9) messenger RNA (mRNA) expression and activity in primary amnion epithelial cells, a process that may lead to preterm premature rupture of membranes. A mechanism that explains MPA's inhibition of TNFα-induced MMP9 mRNA expression and activity in primary amnion epithelial cells is unclear since these cells lack the classic nuclear progesterone receptor but express a membrane-associated progesterone receptor-progesterone receptor membrane component 1 (PGRMC1) along with the glucocorticoid receptor (GR). Primary amnion epithelial cells harvested from healthy term pregnant women at cesarean section were treated with PGRMC1 (to knockdown PGRMC1 expression), GR (to knockdown GR expression), or control small interfering RNA (siRNA; 10 nm) for 72 hours, pretreated with ethanol or MPA (10^-6 M) for 6 hours, and then stimulated with or without TNFα 10 ng/mL for 24 hours. Real-time quantitative polymerase chain reaction and gelatin zymography were used to quantify MMP9 mRNA expression and activity, respectively. Experimental groups were compared using 1-way analysis of variance. Both TNFα-induced MMP9 mRNA expression and activity were significantly inhibited by pretreatment with MPA; however, only the inhibition of TNFα-induced MMP9 activity was partially reversed with PGRMC1 siRNA. However, GR siRNA reversed both the inhibition of TNFα-induced MMP9 mRNA expression and activity by MPA. This study demonstrates that MPA mediates its anti-inflammatory effects primarily through GR and partially through PGRMC1 in primary amnion epithelial cells.

Evaluation of fetal fibronectin for threatened preterm labour in reducing inappropriate interventions

BACKGROUND

Preterm birth is associated with significant perinatal morbidity and mortality. The fetal fibronectin test (fFN) is used to manage women presenting with threatened preterm labour (TPTL).

AIM

To evaluate the use of fFN in women presenting with TPTL with regard to hospital admission, tertiary hospital transfer and use of tocolytics and steroids in our hospital, against recommended guidelines. The ability of fFN <10 ng/mL, 10-49 ng/mL, 50-199 ng/mL and >200 ng/mL to predict outcome was also examined.

MATERIAL AND METHODS

This was a single-centre retrospective study from January 2015 to June 2017. All women who presented to Ipswich hospital, a level two facility for births at >32 weeks of gestation, between 23 and 34⁶  weeks of gestation with TPTL and who had fFN tests were included in the study.

RESULTS

Fetal fibronectin <50 ng/mL had a negative predictive value of 93.5% (95% CI 86.5-97.1). Despite this assurance, one in four presentations resulted in hospital admission and nearly one in ten in steroids and tocolysis administration. Birth <34 weeks was 0% for fFN <10 and 2% for women with fFN levels <200 ng/mL compared to nearly 30% for levels >200 ng/mL.

CONCLUSION

There is noncompliance with use of fFN to its full potential. This small study also provides support for the use of a 200 ng/mL cut-off fFN level for birth <34 weeks. This would avoid the need to transfer to a tertiary facility many women who present with TPTL.

Progesterone treatment enhances the expansion of placental immature myeloid cells in a mouse model of premature labor

INTRODUCTION

immature-myeloid cells (IMCs) are proangiogenic bone marrow (BM)-derived cells that normally differentiate into inflammatory cells such as neutrophils, monocytes and dendritic cells (DCs). We characterized placental IMCs comparing their gene expression and subpopulations to tumor IMCs, and tested our hypothesis that progesterone that inhibits preterm labor, may affect their abundance and differentiation.

METHODS

differences between IMC-subpopulations in subcutaneous tumors versus placentas in C57BL/6 or ICR (CD-1) mice were analyzed by flow cytometry and gene expression was detected by microarrays. BM- and placental cells were incubated with or without progesterone and IMC subpopulations were analyzed. For preterm labor induction pregnant mice pretreated or not with progesterone were or were not treated with Lipopolysaccharide (LPS).

RESULTS

we detected enrichment of granulocytic-IMCs in placentas compared to tumors, paralleled by a decrease in monocytic-IMCs. mRNA expression of placenta- versus tumor IMCs revealed profound transcriptional alterations. Progesterone treated BM-CD11b⁺ cells ex-vivo induced enrichment of granulocytic-IMCs and a decrease in monocytic-IMCs and DCs. LPS treatment in-vivo led to an increase in BM-IMCs in both progesterone pretreated or non-pretreated mice. In the placenta LPS decreased the IMC population while progesterone led to complete abrogation of this effect.

DISCUSSION

placental IMCs differ from tumor-IMCs in both subpopulations and gene expression. Progesterone enhances the proliferation of placenta-specific granulocytic IMCs ex-vivo and LPS induced labor is accompanied by a decrease in placental IMCs only in progesterone non-pretreated mice. We thus speculate that the protective effect of progesterone in preventing preterm labor may be explained at least in part by this specific anti-inflammatory effect.

Does rescue cerclage work?

Rescue cervical cerclage (RCC), also known as emergency cerclage, has long been the subject of controversy. Its use in women who have a dilated cervix has been ambivalent. RCC is often considered as a salvage measure for pregnancies which are at a high risk of severe preterm delivery (PTD) or mid-trimester miscarriage. This study aims to examine and assess the efficacy of RCC and its ability to prolong pregnancy until neonatal viability is achieved. The current data suggest that RCC is associated with a longer latency period frequently resulting in better pregnancy outcomes (Namouz S, Porat S, Okun N, Windrim R, Farine D. Emergency cerclage: literature review. Obstet Gynecol Surv. 2013;68:379-88). This is supported by the Royal College of Obstetricians and Gynaecologists (RCOG) which states that the insertion of a rescue cerclage may delay delivery by a further 5 weeks on average as compared with expectant management or bed rest alone (Shennan AH. To MS: RCOG Green Top Guidelines: Cervical Cerclage RCOG.2011. Available from: www.rcog.org.uk). It further states that it may be associated with a two-fold reduction in the possibility of delivery before 34 weeks of gestation (Shennan AH. To MS: RCOG Green Top Guidelines: Cervical Cerclage RCOG.2011. Available from: www.rcog.org.uk). Our study reveals that the average insertion to delivery interval at our centre was 71.2 days with a live birth rate of 92.5%. A total of 89.1% of women delivered beyond 24 weeks of gestation.

Understanding if, How, and Why Women with Prior Spontaneous Preterm Births are Treated with Progestogens: A National Survey of Obstetrician Practice Patterns

Objective  In 2017, the Society for Maternal-Fetal Medicine (SMFM) Guideline Committee reaffirmed that 17 α -hydroxyprogesterone caproate (17-OHPC) to prevent preterm birth (PTB) is underutilized. We sought to determine what drove progestogen treatment choice of obstetricians managing pregnant women with histories of 1+ singleton spontaneous PTBs (< 37 weeks) who then delivered singleton gestations within the previous 12 months. Subjects  We recruited a nationally representative random sample of obstetricians to abstract medical records of study-qualified patients. Of the 423 study-qualified physicians contacted, 358 (85%) participated; 56 (16%) maternal fetal medicine specialists and 302 (84%) general obstetrician/gynecologists (OB/GYNs) extracted data from 991 eligible patient charts. Results  Almost three-fourths of patients (73.6%) were treated with 17-OHPC; 18.6% received vaginal progesterone, and 11.8% were not treated. Key drivers of physicians' choice to (1) prescribe branded 17-OHPC were "FDA (Food and Drug Administration) approval" (52% relative influence [RI]) and "SMFM guidelines" (24% RI); (2) prescribe vaginal progesterone were "ease of administration" (32% RI) and "shortened cervix" (16% RI); and (3) not provide prophylaxis were "patient not informed of risk" (35% RI) and "no shortened cervix" (29% RI). Conclusion  Study findings support SMFM's contention of continued 17-OHPC underutilization to prevent PTB. Need for additional physician education merits assessment along with appropriate follow-up actions.

Association Between Temporal Changes in Neonatal Mortality and Spontaneous and Clinician-Initiated Deliveries in the United States, 2006-2013

IMPORTANCE

Preterm and postterm deliveries have declined since 2005 in the United States, but the association between these changes and neonatal mortality remains unknown.

OBJECTIVE

To estimate changes in the gestational age distribution among spontaneous and clinician-initiated deliveries between 2006 and 2013 and associated changes in neonatal mortality.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort analysis was conducted of 22 million singleton live births without major malformations in the United States from 2006 to 2013. Data analysis was performed from August to October 2017.

MAIN OUTCOMES AND MEASURES

Changes in gestational age distribution among spontaneous and clinician-initiated deliveries at extremely preterm (20-27 weeks), very preterm (28-31 weeks), moderately preterm (32-33 weeks), late preterm (34-36 weeks), early term (37-38 weeks), term (39-40), late term (41 weeks), and postterm (42-44 weeks) gestations and changes in neonatal mortality rates at less than 28 days between 2006 and 2013. These changes were estimated from log-linear Poisson regression models with robust variance, adjusted for confounders.

RESULTS

Among 22 million births, 12 493 531 (56.7%) were spontaneous and 9 557 815 (43.3%) were clinician-initiated deliveries. Among spontaneous deliveries, the proportion of births at 20 to 27, 28 to 31, 32 to 33, 34 to 36, and 37 to 38 weeks declined. Among clinician-initiated deliveries, the proportion of births at 34 to 36 and 37 to 38 weeks declined and the proportion at 39 to 40 weeks increased. Among spontaneous deliveries, overall neonatal mortality rates declined from 1.8 to 1.3 per 1000 live births, mainly at 20 to 27 weeks (adjusted annual decline, 1%; 95% CI, -2% to -1%) and 28 to 31 weeks (adjusted annual decline, 6%; 95% CI, -8% to -5%). Among clinician-initiated deliveries, overall mortality rates remained unchanged (2.1 to 2.2 per 1000 live births). However, mortality rates declined (0.6 to 0.5 per 1000 live births) at 39 to 40 weeks by 1% (95% CI, -3% to -0.4%) annually, adjusted for confounders.

CONCLUSIONS AND RELEVANCE

In the United States, there was a decline in spontaneous deliveries associated with an overall decline in neonatal mortality. Although clinician-initiated deliveries increased at 39 to 40 weeks, neonatal mortality at that gestation declined.

Cervical cerclage for singleton pregnant patients on vaginal progesterone with progressive cervical shortening

BACKGROUND

Premature cervical ripening plays a significant role in spontaneous preterm birth. Vaginal progesterone is the recommended treatment in singleton pregnancy with incidental short cervix. There is lack of evidence on whether it is beneficial to reinforce the cervix with cerclage when the cervical length becomes progressively shortened <10 mm while on vaginal progesterone.

OBJECTIVE

Our aims are to determine whether cerclage with vaginal progesterone will: (1) reduce the overall spontaneous preterm birth rate, (2) prolong pregnancy latency, and (3) improve neonatal outcomes compared to vaginal progesterone alone.

STUDY DESIGN

This was a retrospective cohort study at the University of Illinois at Chicago of all women with singleton pregnancy on vaginal progesterone for incidental short cervix, cervical length <20 mm. Only those with progressive cervical length shortening <10 mm who delivered at the University of Illinois at Chicago from January 2013 through December 2016 were included. The decision to perform cerclage was based on individual physician preference. Demographic data; information on serial cervical length status; medical, obstetric, and social history; cerclage vs no cerclage; and neonatal outcomes were compared.

RESULTS

A total of 310 women with incidental short cervix on vaginal progesterone were identified, and of these, 75 had progressive shortening cervical length <10 mm and met inclusion criteria. Among the women with extremely shortened cervical length <10 mm, 36 women (48%) had cervical cerclage plus vaginal progesterone, and 39 women (52%) continued on vaginal progesterone alone. The baseline characteristics, mean cervical length (5.06 vs 5.52 mm), and mean gestational age at diagnosis of extreme short cervix (21.5 vs 21.3 weeks) were similar between women who received cerclage vs those who did not, respectively. The mean gestational age at delivery was significantly greater for those with cerclage (34 weeks and 3 days vs 27 weeks and 2 days; P < .001). The rate of spontaneous preterm birth at <37, 35, 32, 28, and 24 weeks were significantly lower in the cerclage group: 44.1% vs 84.2%, 38.2% vs 81.6%, 23.5% vs 78.9%, 14.7% vs 63.2%, and 11.8% vs 39.5%, respectively. The rate of spontaneous preterm birth <37 weeks remained significant after controlling for confounders (relative risk, 0.11; 95% confidence interval, 0.03-0.41; P < .001). The average pregnancy latency was 14 weeks in the cerclage combined with vaginal progesterone group compared to vaginal progesterone alone group. Neonatal intensive care unit admission and development of respiratory distress syndrome were significantly lower in the cerclage group compared to vaginal progesterone alone group: 13 (36.1%) vs 23 (65.7%) (relative risk, 0.55; 95% confidence interval, 0.34-0.90; P = .018) and 8 (22.2%) vs 17 (43.6%) (relative risk, 0.59; 95% confidence interval, 0.29-0.90; P = .027), respectively. Neonates of women with cerclage were also significantly less likely to develop necrotizing enterocolitis or experience neonatal death.

CONCLUSION

Our study showed that cerclage plus vaginal progesterone in women with extremely shortened cervix significantly decreased overall spontaneous preterm birth rates, prolonged pregnancy latency by 2-fold, and decreased the overall neonatal morbidity and mortality.

Intraobserver and interobserver variability in first-trimester transvaginal ultrasound cervical length

Objectives: To determine intraobserver and interobserver variability in the measurement of different cervical length (CL) components at the first trimester (endocervical canal and isthmus), describe the optimum measurement method (single line or two lines) and establish a normality curve of first trimester CL in our population.Methods: Women who attended the first-trimester US scan, between 11.0 and 13.6 weeks of gestation at Vall d'Hebron Universitary Hospital, Barcelona, Spain were included. Inclusion criteria were singleton pregnancies in women over 18 years of age, no gestational complications, uterine malformations or uterine surgery. Lengths of the endocervical canal and uterine isthmus were measured using two methods.Results: Both methods for endocervical canal measurement, single line and two lines, showed low intraobserver variability between examiners, with no statistical differences in the majority of measurements. A correct correlation existed between examiners using the single-line two-line measurements, with a concordance correlation coefficient of 0.76.Conclusions: Cervical length in the first trimester was reproducible for the same physician and between different physicians; however, it is essential to ensure examiners receive adequate training in the technique.

Rescue Adjuvant Vaginal Progesterone May Improve Outcomes in Cervical Cerclage Failure

Introduction Aim of the study was to evaluate the effect of rescue adjuvant vaginal progesterone in women with ongoing, transvaginal ultrasound (TVUS)-confirmed cervical shortening despite cervical cerclage.

Materials and Methods A retrospective case control study was performed of women undergoing cervical surveillance following either history- or ultrasound-indicated cervical cerclage. We compared women managed with cervical cerclage and vaginal progesterone to women managed with cervical cerclage alone. Women with a singleton pregnancy who underwent cervical cerclage were identified from a database. Data on the concurrent use of vaginal progesterone, cervical length measurements, interventions and birth outcomes were collected from patient notes and clinical pathology notes. Patients from each intervention group were matched, based on exact shortest cervical length measurements obtained during surveillance and age of gestation when the measurement was obtained.

Results 66 women were matched and included in the study, based on exact shortest cervical length measurements. Each group had an identical mean shortest cervical length of 12.09 mm. The outcomes of 33 women who received both cervical cerclage and vaginal progesterone were compared to the outcomes of 33 women who were treated with cervical cerclage alone. The administration of vaginal progesterone to women with ongoing cervical shortening despite cervical cerclage was found to significantly prolong the pregnancy (36.36 weeks vs. 32.63 weeks; p = 0.0036) compared to women treated with cerclage alone. This use of rescue adjuvant vaginal progesterone was also associated with higher birth weights (2829 g vs. 2134 g; p = 0.0065) compared to women who had cervical cerclage alone; however, there was no difference in Apgar scores, composite neonatal morbidity or neonatal intensive care admission.

Conclusion Women with cervical shortening despite the presence of cervical cerclage may benefit from further TVUS cervical length surveillance and the administration of vaginal progesterone if further cervical shortening occurs. Despite both groups having clinically significant shortened cervical lengths and cervical cerclage in situ, adjunct vaginal progesterone treatment resulted in older gestational age at birth and higher birth weight. Further investigation and confirmation of this finding in a larger prospective trial is warranted to explore this potential benefit for the management of preterm birth in future.

A soft cervix, categorized by shear-wave elastography, in women with short or with normal cervical length at 18-24 weeks is associated with a higher prevalence of spontaneous preterm delivery

OBJECTIVE

To determine whether a soft cervix identified by shear-wave elastography between 18 and 24 weeks of gestation is associated with increased frequency of spontaneous preterm delivery (sPTD).

MATERIALS AND METHODS

This prospective cohort study included 628 consecutive women with a singleton pregnancy. Cervical length (mm) and softness [shear-wave speed: (SWS) meters per second (m/s)] of the internal cervical os were measured at 18-24 weeks of gestation. Frequency of sPTD <37 (sPTD<37) and <34 (sPTD<34) weeks of gestation was compared among women with and without a short (≤25 mm) and/or a soft cervix (SWS <25th percentile).

RESULTS

There were 31/628 (4.9%) sPTD<37 and 12/628 (1.9%) sPTD<34 deliveries. The combination of a soft and a short cervix increased the risk of sPTD<37 by 18-fold [relative risk (RR) 18.0 (95% confidence interval [CI], 7.7-43.9); P<0.0001] and the risk of sPTD<34 by 120-fold [RR 120.0 (95% CI 12.3-1009.9); P<0.0001] compared to women with normal cervical length. A soft-only cervix increased the risk of sPTD<37 by 4.5-fold [RR 4.5 (95% CI 2.1-9.8); P=0.0002] and of sPTD<34 by 21-fold [RR 21.0 (95% CI 2.6-169.3); P=0.0003] compared to a non-soft cervix.

CONCLUSIONS

A soft cervix at 18-24 weeks of gestation increases the risk of sPTD <37 and <34 weeks of gestation independently of cervical length.

Safety and efficacy of the cervical pessary combined with vaginal progesterone for the prevention of spontaneous preterm birth

INTRODUCTION

The aim of this study was to evaluate the safety and efficacy of the combined treatment of cervical pessary and endovaginal progesterone for the prevention of spontaneous preterm birth (SPB) in women with a short cervical length (CL) between 20 and 24 weeks of gestation.

MATERIALS AND METHODS

This is a prospective study of women with a singleton pregnancy and a sonographically detected mid-trimester CL ≤25 mm. The primary outcome measure was spontaneous delivery before 34 weeks (238 days) of gestation.

RESULTS

The study sample consisted of 90 women with a mean CL of 14.2 mm (SD=6.5 mm). Of the women, 34.4% had at least one risk factor for SPB; 7.8% delivered preterm before 34 weeks of gestation, and 25.6%, before 37 weeks. Neonatal death occurred in two (2.2%) cases due to respiratory distress syndrome. Lower body mass index values, history of preterm delivery and number of second trimester miscarriages were independently associated with delivery before 34 weeks.

CONCLUSION

The combination of vaginal progesterone and cervical pessary for the prevention of SPB in women with a short cervix is safe and well tolerated. This therapy was associated with pregnancy prolongation, reduced prematurity rate and a low rate of perinatal complications.

Predictors of preterm birth

Cervical length (CL) measured by transvaginal ultrasound examination (TVUE) best identifies the risk for preterm birth (PTB). It identifies women at risk who can benefit from corticosteroids or in utero transfer. Early screening improves effectiveness of tocolysis. It reduces iatrogenicity and cost. In preterm premature rupture of membranes (PPROM), CL is devoid of infectious risk and predicts duration of the latency phase but not the risk of perinatal sepsis. Asymptomatic women at risk should be screened at a 2-week interval starting from 16 to 18 weeks, up to 24 weeks. CLs <10th centile are at risk of PTB, especially with decrease in CL after 16 weeks. Repeat ultrasound improves predictive values. Stable CL calls for term delivery. Funneling does not improve predictivity of CL. In twin pregnancies, CL reduces unnecessary interventions. In symptomatic women, fetal fibronectin performs less than CL. Its combination with inconclusive CL has not emerged productive through randomized controlled trials (RCTs), and studies with homogeneous management for preterm labor (PTL) suggest that up to 15% of unjustified hospitalizations and treatment could be avoided.

Prior Uterine Evacuation and the Risk of Short Cervical Length: A Retrospective Cohort Study

OBJECTIVES

To determine whether a prior uterine evacuation procedure is associated with an increased risk of short cervical length (≤20 mm) in women without prior spontaneous preterm birth.

METHODS

This work was a retrospective cohort study from January 2012 to December 2014 of singletons without prior spontaneous preterm birth with cervical length screening between 18 weeks and 23 weeks 6 days. Women with a prior miscarriage/abortion were excluded if management (medical, surgical, or expectant) was not specified. Prior uterine evacuation was defined as dilation and curettage or dilation and evacuation of a spontaneous or induced abortion. The primary outcome was the risk of short cervical length (≤20 mm) among women with and without 1 of more prior uterine evacuations at any gestational age, assessed by the odds ratio and adjusted odds ratio for confounders.

RESULTS

Of 2672 women included, 714 (27%) had at least 1 prior uterine evacuation. The overall incidence of short cervical length in the cohort was 1% (n = 27). Women with at least 1 prior uterine evacuation were more likely to be African American (64% versus 41%; P < .001), smoke (14% versus 8%; P < .001), have a higher body mass index (mean ± SD, 28.1 ± 7.1 versus 26.8 ± 7.1 kg/m² ; P < .001), and have had prior full-term delivery (60% versus 41%; P < .001). Women with at least 1 prior uterine evacuation had a significantly higher incidence of short cervical length (2% versus 0.7%; P = .003; odds ratio, 2.99 [95% confidence interval, 1.40-6.40]). After adjustment for confounders, prior uterine evacuation remained a source of increased risk of short cervical length (adjusted odds ratio, 2.63 [95% confidence interval, 1.19-5.80]).

CONCLUSIONS

Although the overall incidence of short cervical length is low (1%-2%), women with at least 1 prior uterine evacuation have at least a 2-fold increased risk of a short second-trimester cervical length compared to women without a prior uterine evacuation.

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.

The association between serum progesterone level and preterm delivery

OBJECTIVE

To investigate the association of serum progesterone level and preterm delivery.

METHODS

The present prospective cohort study enrolled women with singleton pregnancies attending their first prenatal visit at the outpatient specialist clinics at KK Women's and Children's Hospital, Singapore, between September 1, 2010, and August 31, 2014. Progesterone levels were measured at four clinical visits (visit 1: 9-14 weeks; visit 2: 18-22 weeks; visit 3: 28-32 weeks; visit 4: >34 weeks) and were compared (after adjusting for potential confounders) between patients who had term and preterm deliveries, and among subgroups of spontaneous preterm and iatrogenic preterm deliveries.

RESULTS

There were 708 patients included. Serum progesterone levels at visit 3 were higher in the preterm delivery group than in the term delivery group (P=0.036). The levels did not differ between the two groups at other visits (all P>0.05). In the subgroup analysis, progesterone levels were higher in the iatrogenic preterm delivery subgroup than the term subgroup at visits 1 and 3. A progesterone cut-off level of 304.5 nmol/L demonstrated 81.8% sensitivity, 40.1% specificity, and negative and positive predictive values of 97.5% and 7.2%, respectively, as a predictor of preterm delivery.

CONCLUSION

Higher serum progesterone levels at 28-32 weeks of pregnancy were observed in women who had preterm deliveries; it was weakly predictive of preterm delivery.

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.

Cervical alterations in pregnancy

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

Screening for spontaneous preterm birth and resultant therapies to reduce neonatal morbidity and mortality: A review

Despite considerable effort aimed at decreasing the incidence of spontaneous preterm birth, it remains the leading cause of perinatal morbidity and mortality. Screening strategies are imperfect. Approaches used to identify women considered by historical factors to be low risk for preterm delivery (generally considered to be women with singleton pregnancies without a history of a previous preterm birth) as well as those at high risk for preterm birth (those with a previous preterm birth, short cervix, or multiple gestation) continue to evolve. Herein, we review the current evidence and approaches to screening women for preterm birth, and examine future directions for clinical practice. Further research is necessary to better identify at-risk women and provide evidence-based management.

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.

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.