Vaginal progesterone vs intramuscular 17α-hydroxyprogesterone caproate for prevention of recurrent spontaneous preterm birth in singleton gestations: systematic review and meta-analysis of randomized controlled trials

Cervical elastography using E-Cervix™ for prediction of preterm birth in twin pregnancies with threatened preterm labor

OBJECTIVE

To evaluate the prediction performance of E-Cervix™ for preterm birth in twin pregnancies with threatened preterm labor.

METHODS

This was a single-center retrospective cohort study of twin pregnancies presenting to obstetrics triage for threatened preterm labor (PTL) between 23 0/7 - 33 6/7 weeks who received screening for PTL with transvaginal ultrasound cervical length (TVU CL) and cervical elastography with E-Cervix™ at the time of triage. Cervical elastography parameters were examined and compared between women who delivered preterm and those who did not. The quantification of cervical strain was calculated by a data analysis system that directly analyzes raw data from the region of interest (ROI) and described as hardness ratio (HR), mean strain level within 1 cm from internal (IOS) and external (EOS) os.

RESULTS

63 twin gestations without prior preterm birth and with threatened PTL between 23 0/7 - 33 6/7 weeks of gestation were included in the study. 27 (42.9 %) had cervical length < 25 mm, and were admitted for true PLT. Out of the 36 women with cervical length ≥ 25 mm, 6 (16.7 %) were admitted. Women with threatened PTL had significantly higher HR compared to those with true PTL (p < 0.01), and significantly lower IOS and EOS. Women who delivered preterm had significantly higher HR compared to those who did not delivery preterm and significantly lower IOS and EOS, in overall cohort, and in the subset of women with true PTL. Incidences of HR < 50 % and < 35 % were statistically significantly higher in women who delivered preterm compared to those who did not (p < 0.01).

CONCLUSION

Cervical elastography with E-Cervix™ may be useful for assessment of twin gestations presenting to obstetrics triage for threatened PTL.

Prevention of spontaneous preterm delivery – an update on where we are today

Spontaneous preterm birth (delivery before 37 completed weeks) is the single most important cause of perinatal morbidity and mortality. The rate is increasing world-wide with a great disparity between low, middle and high income countries. It has been estimated that the cost of neonatal care for preterm babies is more than 4 times that of a term neonate admitted into the neonatal care. Furthermore, there are high costs associated with long-term morbidity in those who survive the neonatal period. Interventions to stop delivery once preterm labor starts are largely ineffective hence the best approach to reducing the rate and consequences is prevention. This is either primary (reducing or minimizing factors associated with preterm birth prior to and during pregnancy) or secondary - identification and amelioration (if possible) of factors in pregnancy that are associated with preterm labor. In the first category are optimizing maternal weight, promoting healthy nutrition, smoking cessation, birth spacing, avoidance of adolescent pregnancies and screening for and controlling various medical disorders as well as infections prior to pregnancy. Strategies in pregnancy, include early booking for prenatal care, screening and managing medical disorders and their complications, and identifying predisposing factors to preterm labor such as shortening of the cervix and timely instituting progesterone prophylaxis or cervical cerclage where appropriate. The use of biomarkers such as oncofetal fibronectin, placental alpha-macroglobulin-1 and IGFBP-1 where cervical screening is not available or to diagnosis PPROM would identify those that require close monitoring and allow the institution of antibiotics especially where infection is considered a predisposing factor. Irrespective of the approach to prevention, timing the administration of corticosteroids and where necessary tocolysis and magnesium sulfate are associated with an improved outcome. The role of genetics, infections and probiotics and how these emerging dimensions help in the diagnosis of preterm birth and consequently prevention are exciting and hopefully may identify sub-populations for targeted strategies.

A Comparison of Vaginal and Intramuscular Progesterone for the Prevention of Recurrent Preterm Birth

OBJECTIVE

This study aimed to examine whether vaginal progesterone is noninferior to 17-α hydroxyprogesterone caproate (17OHP-C) in the prevention of recurrent preterm birth (PTB).

STUDY DESIGN

This retrospective cohort study included singleton pregnancies among women with a history of spontaneous PTB who received prenatal care at a single tertiary center from 2011 to 2016. Pregnancies were excluded if progesterone was not initiated prior to 24 weeks or the fetus had a major congenital anomaly. The primary outcome was PTB <37 weeks. A priori, noninferiority was to be established if the upper bound of the adjusted two-sided 90% confidence interval (CI) for the difference in PTB fell below 9%. Inverse probability of treatment weighting (IPTW) was used to carefully control for confounding associated with choice of treatment and PTB. Adjusted differences in PTB proportions were estimated via IPTW regression, with standard errors adjustment for multiple pregnancies per woman. Secondary outcomes included PTB <34 and <28 weeks, spontaneous PTB, neonatal intensive care unit admission, and gestational age at delivery.

RESULTS

Among 858 pregnancies, 41% (n = 353) received vaginal progesterone and 59% (n = 505) were given 17OHP-C. Vaginal progesterone use was more common later in the study period, and among women who established prenatal care later, had prior PTBs at later gestational ages, and whose race/ethnicity was neither non-Hispanic white nor non-Hispanic Black. Vaginal progesterone did not meet noninferiority criteria compared with 17-OHPC in examining PTB <37 weeks, with an IPTW adjusted difference of 3.4% (90% CI: -3.5, 10.3). For secondary outcomes, IPTW adjusted differences between treatment groups were generally small and CIs were wide.

CONCLUSION

We could not conclude noninferiority of vaginal progesterone to 17OHP-C; however, women and providers may be willing to accept a larger difference (>9%) when considering the cost and availability of vaginal progesterone versus 17OHP-C. A well-designed randomized trial is needed.

KEY POINTS

· Vaginal progesterone is not noninferior to 17OHP-C.. · PTB risk may be 10% higher with vaginal progesterone.. · Associations did not differ based on obesity status..

Resistance to Change

Advances in medical technology do not follow a smooth process and are highly variable. Implementation can occasionally be rapid, but often faces varying degrees of resistance resulting at the very least in delayed implementation. Using qualitative comparative analysis, we have evaluated numerous technological advances from the perspective of how they were introduced, implemented, and opposed. Resistance varies from benign - often happening because of inertia or lack of resources to more active forms, including outright opposition using both appropriate and inappropriate methods to resist/delay changes in care. Today, even public health has become politicized, having nothing to do with the underlying science, but having catastrophic results. Two other corroding influences are marketing pressure from the private sector and vested interests in favor of one outcome or another. This also applies to governmental agencies. There are a number of ways in which papers have been buried including putting the thumb on the scale where reviewers can sabotage new ideas. Unless we learn to harness new technologies earlier in their life course and understand how to maneuver around the pillars of obstruction to their implementation, we will not be able to provide medical care at the forefront of technological capabilities.

Prevention of Pregnancy Loss: Combining Progestogen Treatment and Psychological Support

Pregnancy loss can be defined as a loss before either 20 or 24 weeks of gestation (based on the first day of the last menstrual period) or the loss of an embryo or fetus less than 400 g in weight if the gestation age is unknown. Approximately 23 million pregnancy losses occur worldwide every year, equating to 15-20% of all clinically recognized pregnancies. A pregnancy loss is usually associated with physical consequences, such as early pregnancy bleeding ranging in severity from spotting to hemorrhage. However, it can also be associated with profound psychological distress, which can be felt by both partners and may include feelings of denial, shock, anxiety, depression, post-traumatic stress disorder, and suicide. Progesterone plays a key part in the maintenance of a pregnancy, and progesterone supplementation has been assessed as a preventative measure in patients at increased risk of experiencing a pregnancy loss. The primary objective of this piece is to assess the evidence for various progestogen formulations in the treatment of threatened and recurrent pregnancy loss, postulating that an optimal treatment plan would preferably include a validated psychological support tool as an adjunct to appropriate pharmacological treatment.

GRADE Use in Evidence Syntheses Published in High-Impact-Factor Gynecology and Obstetrics Journals: A Methodological Survey

Objective: To identify and describe the certainty of evidence of gynecology and obstetrics systematic reviews (SRs) using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Method: Database searches of SRs using GRADE, published between 1 January 2016 to 31 December 2020, in the 10 "gynecology and obstetrics" journals with the highest impact factor, according to the Journal Citation Report 2019. Selected studies included those SRs using the GRADE approach, used to determine the certainty of evidence. Results: Out of 952 SRs, ninety-six SRs of randomized control trials (RCTs) and/or nonrandomized studies (NRSs) used GRADE. Sixty-seven SRs (7.04%) rated the certainty of evidence for specific outcomes. In total, we identified 946 certainty of evidence outcome ratings (n = 614 RCT ratings), ranging from very-low (42.28%) to low (28.44%), moderate (17.65%), and high (11.63%). High and very low certainty of evidence ratings accounted for 2.16% and 71.60% in the SRs of NRSs, respectively, compared with 16.78% and 26.55% in the SRs of RCTs. In the SRs of RCTs and NRSs, certainty of evidence was mainly downgraded due to imprecision and bias risks. Conclusions: More attention needs to be paid to strengthening GRADE acceptance and building knowledge of GRADE methods in gynecology and obstetrics evidence synthesis.

The effectiveness of vaginal progesterone in reducing preterm birth in high-risk patients diagnosed with short cervical length after 24 weeks: A retrospective cohort study

Objective

To assess the impact of progesterone treatment on maternal and neonatal outcomes in women with a history of preterm birth and short cervical length diagnosed after 24 weeks of gestation.

Methods

A retrospective cohort study included women with a history of preterm birth and a transvaginal sonographic cervical length measurement of ≤ 25 mm, diagnosed between 24⁺⁰ and 33⁺⁶ weeks of gestation. Exclusion criteria included prior progesterone treatment, cervical cerclage, or pessary. The study population was divided into the progesterone treatment group and the non-treatment group.

Results

The study included 104 women, with 46.2% (48/104) receiving progesterone treatment and 53.8% (56/104) not receiving treatment. The rate of spontaneous preterm birth before 37 weeks of gestation was 43% (24/56) in the non-treatment group and 31% (15/48) in the progesterone treatment group (P = 0.14); the rate of spontaneous preterm birth before 34 weeks was 7% (4/56) in the non-treatment group and 0% (0/48) in the progesterone treatment group (P = 0.05). Progesterone treatment was associated with a significant decrease in neonatal intensive care unit admissions (OR 0.20, 95% CI 0.05-0.74) and in the neonatal hospitalization period (mean difference in days 2.43, 95% CI 0.44-4.42). The risk of recurrent spontaneous preterm birth was highest (71%) among women with two or more previous preterm deliveries who did not receive progesterone treatment, and lowest (24%) among women with one previous preterm delivery who received progesterone treatment.

Conclusion

Progesterone treatment was associated with a reduction in rates of spontaneous preterm birth before 34 weeks of gestation, neonatal intensive care unit admission, and neonatal length of stay in high-risk patients, even when initiated after 24 weeks of gestation.

Interventions for the prevention of spontaneous preterm birth: a scoping review of systematic reviews

BACKGROUND

Globally, 11% of babies are born preterm each year. Preterm birth (PTB) is a leading cause of neonatal death and under-five mortality and morbidity, with lifelong sequelae in those who survive. PTB disproportionately impacts low/middle-income countries (LMICs) where the burden is highest.

OBJECTIVES

This scoping review sought to the evidence for interventions that reduce the risk of PTB, focusing on the evidence from LMICs and describing how context is considered in evidence synthesis.

DESIGN

We conducted a scoping review, to describe this wide topic area. We searched five electronic databases (2009-2020) and contacted experts to identify relevant systematic reviews of interventions to reduce the risk of PTB. We included published systematic reviews that examined the effectiveness of interventions and their effect on reducing the risk of PTB. Data were extracted and is described narratively.

RESULTS

139 published systematic reviews were included in the review. Interventions were categorised as primary or secondary. The interventions where the results showed a greater effect size and consistency across review findings included treatment of syphilis and vaginal candidiasis, vitamin D supplementation and cervical cerclage. Included in the 139 reviews were 1372 unique primary source studies. 28% primary studies were undertaken in LMIC contexts and only 4.5% undertaken in a low-income country (LIC) Only 10.8% of the reviews sought to explore the impact of context on findings, and 19.4% reviews did not report the settings or the primary studies.

CONCLUSION

This scoping review highlights the lack of research evidence derived from contexts where the burden of PTB globally is greatest. The lack of rigour in addressing contextual applicability within systematic review methods is also highlighted. This presents a risk of inappropriate and unsafe recommendations for practice within these contexts. It also highlights a need for primary research, developing and testing interventions in LIC settings.

Vaginal progesterone compared with intramuscular 17-alpha-hydroxyprogesterone caproate for prevention of recurrent preterm birth in singleton gestations: a systematic review and meta-analysis

OBJECTIVE

Randomized trials have found benefits of both vaginal progesterone and 17-alpha-hydroxyprogesterone caproate in the prevention of recurrent preterm birth. A previous meta-analysis directly comparing the two was limited by low-quality evidence, and national and international society guidelines remain conflicting regarding progestin formulation recommended for prevention of recurrent preterm birth. The aim of this updated systematic review with meta-analysis was to evaluate the efficacy of vaginal progesterone compared with 17-alpha-hydroxyprogesterone caproate in the prevention of spontaneous preterm birth in patients with singleton gestations and previous spontaneous preterm birth.

DATA SOURCES

Searches were performed in MEDLINE, Ovid, Scopus, ClinicalTrials.gov, the International Prospective Register of Systematic Reviews (PROSPERO), SciELO, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) with the use of a combination of keywords and text words related to "preterm birth," "preterm delivery," "singleton," "cervical length," "progesterone," "progestogens," "vaginal," "17-alpha-hydroxy-progesterone caproate," and "intramuscular" from inception of each database to September 2021. No restrictions for language or geographic location were applied.

STUDY ELIGIBILITY CRITERIA

We included all randomized controlled trials of asymptomatic singleton gestations with previous spontaneous preterm birth that were randomized to prophylactic treatment with either vaginal progesterone (ie, intervention group) or intramuscular 17-alpha-hydroxyprogesterone caproate (ie, comparison group). Post hoc sensitivity analysis was performed for studies with low risk of bias and studies with protocol registration.

METHODS

The primary outcome was preterm birth <34 weeks' gestation. The summary measures were reported as relative risks with 95% confidence intervals.

RESULTS

Seven randomized controlled trials including 1910 patients were included in the meta-analysis. Patients who received vaginal progesterone had a significantly lower rate of preterm birth at <34 weeks (14.7% vs 19.9%; relative risk, 0.74; 95% confidence interval, 0.57-0.96), preterm birth at <37 weeks (36.0% vs 46.6%; relative risk, 0.76; 95% confidence interval, 0.69-0.85), and preterm birth at <32 weeks of gestation (7.9% vs 13.6%; relative risk, 0.58; 95% confidence interval, 0.39-0.86), compared with women who received intramuscular 17-alpha-hydroxyprogesterone caproate. There were no significant differences in the rate of preterm birth at <28 weeks' gestation. Adverse drug reactions were significantly lower in the vaginal progesterone group than in the 17-alpha-hydroxyprogesterone caproate group (15.6% vs 22.2%; relative risk, 0.71; 95% confidence interval, 0.54-0.92). Perinatal mortality was lower in the vaginal progesterone group than in the 17-alpha-hydroxyprogesterone caproate group (2.2% vs 4.4%; relative risk, 0.51; 95% confidence interval, 0.25-1.01). In sensitivity analysis including trials rated with at least 4 Cochrane tools as of "low risk of bias," 4 trials were included (N=575), and there was no longer a significant difference in preterm birth at <34 weeks' gestation between vaginal progesterone and 17-alpha-hydroxyprogesterone caproate (12.2% vs 13.9%; relative risk, 0.87; 95% confidence interval, 0.57-1.32).

CONCLUSION

Overall, vaginal progesterone was superior to 17-alpha-hydroxyprogesterone caproate in the prevention of preterm birth at <34 weeks' gestation in singleton pregnancies with previous spontaneous preterm birth. Although sensitivity analysis of high-fidelity studies showed the same trend, findings were no longer statistically significant.

Vaginal progesterone vs intramuscular 17-hydroxyprogesterone caproate for prevention of recurrent preterm birth: a randomized controlled trial

BACKGROUND

Preterm birth is the leading cause of neonatal morbidity and mortality, and previous preterm birth is one of the strongest risk factors for preterm birth. National and international obstetrical societies have different recommendations regarding progesterone formulation for the prevention of recurrent preterm birth.

OBJECTIVE

This study aimed to determine whether vaginal progesterone is superior to 17-hydroxyprogesterone caproate in the prevention of recurrent preterm birth in patients with singleton pregnancies who had a previous spontaneous preterm birth.

STUDY DESIGN

This was an open-label multicenter pragmatic randomized controlled trial at 5 US centers of patients with singleton pregnancies at <24 weeks of gestation who had a previous spontaneous preterm birth randomized 1:1 to either 200 mg vaginal progesterone suppository nightly or 250 mg intramuscular 17-hydroxyprogesterone caproate weekly from 16 to 36 weeks of gestation. Based on the estimated recurrent preterm birth rate of 36% with 17-hydroxyprogesterone caproate, 95 participants were needed in each arm to detect a 50% reduction in preterm birth rate with vaginal progesterone, with 80% power and 2-sided alpha of 0.05. The primary outcome was preterm birth at <37 weeks of gestation. Prespecified secondary outcomes included preterm birth at <34 and <28 weeks of gestation, mean gestational age at delivery, neonatal morbidity and mortality, and measures of adherence. Analysis was by intention to treat. The chi-square test and Student t test were used as appropriate. P<.05 was considered significant.

RESULTS

Overall, 205 participants were randomized; 94 participants in the vaginal progesterone group and 94 participants in 17-hydroxyprogesterone caproate group were included. Although gestational age at enrollment was similar, those assigned to vaginal progesterone initiated therapy earlier (16.9±1.4 vs 17.8±2.5 weeks; P=.001). Overall continuation of assigned formulation until delivery was similar (73% vs 69%; P=.61). There was no significant difference in preterm birth at <37 (31% vs 38%; P=.28; relative risk, 0.81 [95% confidence interval, 0.54-1.20]), <34 (9.6% vs 14.9%; P=.26; relative risk, 0.64 [95% confidence interval, 0.29-1.41]), or <28 (1.1% vs 4.3%; P=.37; relative risk, 0.25 [95% confidence interval, 0.03-2.20]) weeks of gestation. Participants in the vaginal progesterone group had a later mean gestational age at delivery than participants in the 17-hydroxyprogesterone caproate group (37.36±2.72 vs 36.34±4.10 weeks; mean difference, 1.02 [95% confidence interval, 0.01-2.01]; P=.047).

CONCLUSION

Vaginal progesterone did not reduce the risk of recurrent preterm birth by 50% compared with 17-OHPC; however, vaginal progesterone may lead to increased latency to delivery. This trial was underpowered to detect a smaller, but still clinically significant, difference in the efficacy of preterm birth prevention. Patient factors that impact adherence and ability to obtain medication in a timely fashion should be included in counseling on progesterone selection.

Prevention of Preterm Birth by Cervical Pessary Combined with Vaginal Progesterone: a Systematic Review and Meta-analysis with Trial Sequential Analysis

This study was to assess the effectiveness of cervical pessary combined with vaginal progesterone for the prevention of preterm birth (PTB). Ten studies about singleton [five randomized controlled trials (RCTs), vs vaginal progesterone; four cohorts, vs vaginal progesterone; two cohorts, vs cervical cerclage + vaginal progesterone] and two cohort studies about multiple pregnancies (vs vaginal progesterone) were included after searching electronic databases. For singleton pregnancies, the meta-analysis of three non-RCTs [relative risk (RR) = 0.41, p = 0.001] or total trials in non-Asian country (RR = 0.56, p = 0.03) revealed that compared with vaginal progesterone alone, cervical pessary + vaginal progesterone treatment had significant effectiveness on preventing PTB < 34 weeks, but not for five RCTs; meta-analysis of two trials showed that cervical pessary + vaginal progesterone had no significant prevention effects of PTB compared with cervical cerclage + vaginal progesterone. For multiple pregnancies, meta-analysis of two trials showed that compared with vaginal progesterone, cervical pessary + vaginal progesterone treatment increased neonatal birth weight (standardized mean difference = 0.50, p = 0.01). Trial sequential analysis implied additional studies were required. Four studies vs other controls (pessary, three-combined, tocolysis, conservative or no treatment; one study, each) were selected for systematic review. In conclusion, cervical pessary combined with vaginal progesterone may be safe and effective to prevent PTB in singleton pregnancies and increase neonatal birth weight in the multiple pregnancies compared with vaginal progesterone alone.

Fetal Membranes Contribute to Drug Transport across the Feto-Maternal Interface Utilizing the Breast Cancer Resistance Protein (BCRP)

During pregnancy, the placenta is established as a primary organ for drug transport at the maternal-fetal interface. The fetal membranes (FM) also form an interface with maternal tissues; however, their role in drug transport has not been previously investigated. Knowledge of drug transport across this feto-maternal interface along with the placenta can improve new drug development and testing for use during pregnancy. We also hypothesize that extracellular vesicles (exosomes 30–160 nm) released from the FM and placental cells may also contain drug transport proteins and might impact drug trafficking across the feto-maternal interfaces. The objectives were to (1) localize the breast cancer resistance protein (BCRP) in human FM; (2) determine the drug transport function of BCRP in chorion trophoblast cells (CTCs) of the FM; and (3) investigate the presence of BCRP in FM cell-derived exosomes, as a paracrine modifier of the tissue environment for transport functions. The gene and protein expressions of ABCG2/BCRP in FMs were determined by quantitative real-time PCR (qRT-PCR) and western blotting (WB) and were localized by immunohistochemistry (IHC). The surface expression of BCRP in FM cells was determined by flow cytometry. The functional role of BCRP was assessed by an EFFLUX dye multidrug resistance assay. The presence of BCRP in exosomes derived from CTCs and BeWo cells was examined using ExoView^®. Data derived from CTCs are compared with placental trophoblast cells (BeWo). BCRP is expressed and localized in the fetal membrane, primarily in the chorion trophoblast cell layer and scarcely in the amnion epithelial layer (AEC), and primarily localized on both AEC and CTC cell surfaces. Efflux assay data showed that FM cells have similar drug resistance activity as BeWo cells, suggesting that FM also have drug transportation capabilities. BeWo- and CTC-derived exosomes expressed limited BCRP protein on the surface, so it was predominantly contained in the exosomal lumen. As far as we are aware, this is the first study to report BCRP expression in fetal membrane cells and as cargo in fetal membrane-derived exosomes. We report that fetal membrane cells are capable of drug transportation. Based on these results, investigational drug trials should include the FM and its exosomes as possible drug transportation routes in pregnancy.

17-Alpha-Hydroxyprogesterone vs. Placebo for Preventing of Recurrent Preterm Birth: A Systematic Review and Meta-Analysis of Randomized Trials

Background: Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality. Objective: To estimate the effect of 17-alpha-hydroxyprogesterone caproate (17-OHPC) compared to placebo in singleton gestations for reducing the risk of recurrent PTB and neonatal morbidity and mortality. Work Design: Systematic review and meta-analysis. Search Strategy: Searching MEDLINE, Embase, Web of Science, SCOPUS, Cochrane Library, and clinical trial registries. Selection Criteria: Randomized controlled trials of singleton gestations with a history of PTB and treated with a weekly intramuscular injection of 17-OHPC or placebo. Data Collection and Analysis: A random meta-analysis model was performed for the PTB outcomes (<32, <35, and <37 weeks) and neonatal outcomes (neonatal death, grade 3 or 4 intraventricular hemorrhage, respiratory distress syndrome, bronchopulmonary dysplasia, necrotizing enterocolitis, and sepsis). Effect estimates were measured by relative risk ratio (RR) with a 95% confidence interval (CI). Main Results: Six works were included. There were no statistically significant reductions in the PTB risk following the use of 17-OHPC at <32 weeks (RR = 0.61, 95% CI: 0.13-2.77, and I ² = 39%), <35weeks (RR = 0.60, 95% CI: 0.10-3.67, and I ² = 51%), and <37 weeks (RR = 0.68, 95% CI: 0.46-1, and I ² = 75%). Furthermore, all the neonatal outcomes were statistically similar between the two groups. Conclusion: Treatment with 17-OHPC is not associated with reducing the risk of PTB or neonatal outcomes compared to placebo.

A systematic review and meta-analysis of obstetric and maternal outcomes after prior uterine artery embolization

This study aimed to review the obstetric complications during subsequent pregnancies after uterine artery embolization (UAE) for postpartum hemorrhage (PPH) by exploring the relationship between prior UAE and obstetric complications through a meta-analysis. We conducted a systematic literature review through March 31, 2021, using PubMed, Scopus, and the Cochrane Central Register of Controlled Trials in compliance with the PRISMA guidelines and determined the effect of prior UAE for PPH on the rate of placenta accreta spectrum (PAS), PPH, placenta previa, hysterectomy, fetal growth restriction (FGR), and preterm birth (PTB). Twenty-three retrospective studies (2003–2021) met the inclusion criteria. They included 483 pregnancies with prior UAE and 320,703 pregnancies without prior UAE. The cumulative results of all women with prior UAE indicated that the rates of obstetric complications PAS, hysterectomy, and PPH were 16.3% (34/208), 6.5% (28/432), and 24.0% (115/480), respectively. According to the patient background-matched analysis based on the presence of prior PPH, women with prior UAE were associated with higher rates of PAS (odds ratio [OR] 20.82; 95% confidence interval [CI] 3.27–132.41) and PPH (OR 5.32, 95% CI 1.40–20.16) but not with higher rates of hysterectomy (OR 8.93, 95% CI 0.43–187.06), placenta previa (OR 2.31, 95% CI 0.35–15.22), FGR (OR 7.22, 95% CI 0.28–188.69), or PTB (OR 3.00, 95% CI 0.74–12.14), compared with those who did not undergo prior UAE. Prior UAE for PPH may be a significant risk factor for PAS and PPH during subsequent pregnancies. Therefore, at the time of delivery, clinicians should be more attentive to PAS and PPH when women have undergone prior UAE. Since the number of women included in the patient background-matched study was limited, further investigations are warranted to confirm the results of this study.

Prediction and Prevention of Spontaneous Preterm Birth: ACOG Practice Bulletin, Number 234

Preterm birth is among the most complex and important challenges in obstetrics. Despite decades of research and clinical advancement, approximately 1 in 10 newborns in the United States is born prematurely. These newborns account for approximately three-quarters of perinatal mortality and more than one half of long-term neonatal morbidity, at significant social and economic cost (1-3). Because preterm birth is the common endpoint for multiple pathophysiologic processes, detailed classification schemes for preterm birth phenotype and etiology have been proposed (4, 5). In general, approximately one half of preterm births follow spontaneous preterm labor, about a quarter follow preterm prelabor rupture of membranes (PPROM), and the remaining quarter of preterm births are intentional, medically indicated by maternal or fetal complications. There are pronounced racial disparities in the preterm birth rate in the United States. The purpose of this document is to describe the risk factors, screening methods, and treatments for preventing spontaneous preterm birth, and to review the evidence supporting their roles in clinical practice. This Practice Bulletin has been updated to include information on increasing rates of preterm birth in the United States, disparities in preterm birth rates, and approaches to screening and prevention strategies for patients at risk for spontaneous preterm birth.

Vaginal progesterone for prevention of preterm birth in asymptomatic high-risk women with a normal cervical length: a systematic review and meta-analysis protocol

BACKGROUND

Preterm birth (PTB) is estimated to affect 14.9 million babies globally every year. Global rates of PTB continue to increase from 9.8 to 10.6% over a 15-year period from 2000 to 2014. Vaginal progesterone is commonly used by clinicians as a prevention strategy, with recent evidence affirming the benefit of vaginal (micronised) progesterone to prevent PTB in women with a shortened cervix (< 25 mm). Given the low incidence of a short cervix at mid-gestation in high-risk populations further evidence is required. The objective of this review is to determine if vaginal progesterone reduces spontaneous preterm birth (sPTB) before 37 weeks in asymptomatic high-risk women with a singleton pregnancy with a normal mid-gestation cervical length.

METHODS

Studies will be sourced from MEDLINE, Embase and Cochrane Register of Trials (CENTRAL) from their inception onwards with the search terms 'progesterone' and 'preterm birth'. Studies will be screened and included if they assess vaginal progesterone compared to placebo in women with a normal cervical length. The primary outcome will be sPTB < 37 weeks, with secondary outcomes of sPTB < 34 weeks. Two independent reviewers will conduct study screening at abstract and full text level, data extraction and risk of bias assessment with disagreements resolved by an experienced researcher. The Mantel-Haenszel statistical method and random effects analysis model will be used to produce treatment effect odds ratios and corresponding 95% confidence intervals.

DISCUSSION

This review will assess the current body of evidence and provide clarity regarding the potential benefits and best practice of use of vaginal progesterone in asymptomatic women with high-risk singleton pregnancies and normal cervical length.

TRIAL REGISTRATION

PROSPERO CRD42020152051.

Evaluating Progestogens for Preventing Preterm birth International Collaborative (EPPPIC): meta-analysis of individual participant data from randomised controlled trials

BACKGROUND

Preterm birth is a global health priority. Using a progestogen during high-risk pregnancy could reduce preterm birth and adverse neonatal outcomes.

METHODS

We did a systematic review of randomised trials comparing vaginal progesterone, intramuscular 17-hydroxyprogesterone caproate (17-OHPC), or oral progesterone with control, or with each other, in asymptomatic women at risk of preterm birth. We identified published and unpublished trials that completed primary data collection before July 30, 2016, (12 months before data collection began), by searching MEDLINE, Embase, CINAHL, the Maternity and Infant Care Database, and relevant trial registers between inception and July 30, 2019. Trials of progestogen to prevent early miscarriage or immediately-threatened preterm birth were excluded. Individual participant data were requested from investigators of eligible trials. Outcomes included preterm birth, early preterm birth, and mid-trimester birth. Adverse neonatal sequelae associated with early births were assessed using a composite of serious neonatal complications, and individually. Adverse maternal outcomes were investigated as a composite and individually. Individual participant data were checked and risk of bias assessed independently by two researchers. Primary meta-analyses used one-stage generalised linear mixed models that incorporated random effects to allow for heterogeneity across trials. This meta-analysis is registered with PROSPERO, CRD42017068299.

FINDINGS

Initial searches identified 47 eligible trials. Individual participant data were available for 30 of these trials. An additional trial was later included in a targeted update. Data were therefore available from a total of 31 trials (11 644 women and 16185 offspring). Trials in singleton pregnancies included mostly women with previous spontaneous preterm birth or short cervix. Preterm birth before 34 weeks was reduced in such women who received vaginal progesterone (nine trials, 3769 women; relative risk [RR] 0·78, 95% CI 0·68-0·90), 17-OHPC (five trials, 3053 women; 0·83, 0·68-1·01), and oral progesterone (two trials, 181 women; 0·60, 0·40-0·90). Results for other birth and neonatal outcomes were consistently favourable, but less certain. A possible increase in maternal complications was suggested, but this was uncertain. We identified no consistent evidence of treatment interaction with any participant characteristics examined, although analyses within subpopulations questioned efficacy in women who did not have a short cervix. Trials in multifetal pregnancies mostly included women without additional risk factors. For twins, vaginal progesterone did not reduce preterm birth before 34 weeks (eight trials, 2046 women: RR 1·01, 95% CI 0·84-1·20) nor did 17-OHPC for twins or triplets (eight trials, 2253 women: 1·04, 0·92-1·18). Preterm premature rupture of membranes was increased with 17-OHPC exposure in multifetal gestations (rupture <34 weeks RR 1·59, 95% CI 1·15-2·22), but we found no consistent evidence of benefit or harm for other outcomes with either vaginal progesterone or 17-OHPC.

INTERPRETATION

Vaginal progesterone and 17-OHPC both reduced birth before 34 weeks' gestation in high-risk singleton pregnancies. Given increased underlying risk, absolute risk reduction is greater for women with a short cervix, hence treatment might be most useful for these women. Evidence for oral progesterone is insufficient to support its use. Shared decision making with woman with high-risk singleton pregnancies should discuss an individual's risk, potential benefits, harms and practicalities of intervention. Treatment of unselected multifetal pregnancies with a progestogen is not supported by the evidence.

FUNDING

Patient-Centered Outcomes Research Institute.

Mid-trimester miscarriage and subsequent pregnancy outcomes: the role of cervical insufficiency in a cohort of 175 cases

OBJECTIVE

To evaluate the causes of MTM and their impact on subsequent pregnancies.

MATERIAL AND METHODS

A retrospective single-center cohort study of all pregnancies with a second-trimester pregnancy loss between 14 weeks and 21 weeks + 6 days gestation, excluding terminations of pregnancy (TOP) and in utero fetal deaths. Predefined criteria were used to allocate cases to one of 6 primary etiologic diagnoses: cervical insufficiency, chorioamnionitis, placental anomalies, fetal anomalies, iatrogenic causes, or abdominal trauma.

RESULTS

Among 578 mid-trimester fetal losses, 175 were MTM, a prevalence of 5.7 per 1000 live births in the center. The suspected primary cause was cervical insufficiency in 76 cases (43.4%), chorioamnionitis in 59 (33.7%), placental anomalies or preterm premature rupture of membranes in 26 (14.8%), iatrogenic in 8 (4.6%), trauma in 3 (1.7%), and undetermined in 3 cases (1.7%). A subsequent pregnancy beyond 14 WG was recorded for 78 patients. Recurrent MTM occurred in 21.8% and preterm deliveries in 14.1% ; 13% of patients without evidence of cervical insufficiency in the index pregnancy required emergency cerclage.

CONCLUSION

Cervical insufficiency was the leading cause of MTM, with a high risk of recurrent MTM or preterm birth, thus prophylactic cerclage or cervical length measurements should be considered for subsequent pregnancies.

Investigating the Metabolic Model in Preterm Neonates by Tandem Mass Spectrometry: A Cohort Study

The changes of metabolite profiles in preterm birth have been demonstrated using newborn screening data. However, little is known about the holistic metabolic model in preterm neonates. The aim was to investigate the holistic metabolic model in preterm neonates. All metabolite values were obtained from a cohort data of routine newborn screening. A total of 261 758 newborns were recruited and randomly divided into a training subset and a testing subset. Using the training subset, 949 variates were considered to establish a logistic regression model for identifying preterm birth (<37 weeks) from term birth (≥37 weeks). Sventy-two variates (age at collection, TSH, 17α-OHP, proline, tyrosine, C16:1-OH, C18:2, and 65 ratios) entered into the final metabolic model for identifying preterm birth from term birth. Among the variates entering into the final model of PTB [Leucine+Isoleucine+Proline-OH)/Valine (OR=38.36], (C3DC+C4-OH)/C12 (OR=15.58), Valine/C5 (OR=6.32), [Leucine+isoleucine+Proline-OH)/Ornithine (OR=2.509)], and Proline/C18:1 (OR=2.465) have the top five OR values, and [Leucine+Isoleucine+Proline-OH)/C5 (OR=0.05)], [Leucine+Isoleucine+Proline-OH)/Phenylalanine (OR=0.214)], proline/valine (OR=0.230), C16/C18 (OR=0.259), and Alanine/free carnitine (OR=0.279) have the five lowest OR values. The final metabolic model had a capacity of identifying preterm infants with >80% accuracy in both the training and testing subsets. When identifying neonates ≤32 weeks from those >32 weeks, it had a robust performance with nearly 95% accuracy in both subsets. In summary, we have established an excellent metabolic model in preterm neonates. These findings could provide new insights for more efficient nutrient supplements and etiology of preterm birth.

Cervical pessary in singleton gestations with arrested preterm labor: a randomized clinical trial

BACKGROUND

Cervical pessary has been proven to be effective in reducing the rate of preterm birth in asymptomatic women with singleton gestations and short cervical length in the midtrimester of pregnancy; however, the efficacy of this device in women with arrested preterm labor is still a subject of debate.

OBJECTIVE

This study aimed to test the hypothesis that the use of a cervical pessary in women with singleton pregnancy and arrested preterm labor would reduce the risk of preterm birth at <37 weeks of gestation.

STUDY DESIGN

This study is a parallel group, nonblinded, randomized trial. Participants included in the study were women with a diagnosis of arrested preterm labor between 24 0/7 and 33 6/7 weeks of gestations. The participants were randomized to either the cervical pessary group or no pessary group in a 1:1 ratio. The primary endpoint was preterm birth at <37 weeks of gestation. A sample size of 120 participants was determined, but the trial was concluded before the completion of enrollment.

RESULTS

A total of 61 women with singleton pregnancies and arrested preterm labor at 24 0/7 to 33 6/7 weeks of gestation were enrolled in the trial. Of the 61 women, 32 were randomized to the cervical pessary group and 29 to the control group. Preterm birth at <37 weeks of gestation occurred in 14 women (43.8%) in the pessary group and 6 women (20.7%) in the control group (relative risk, 2.98; 95% confidence interval, 0.96-9.30).

CONCLUSION

In this underpowered trial, among women with singleton pregnancies and arrested preterm labor, compared with no pessary use, the use of a cervical pessary does not result in a lower rate of preterm birth at <37 weeks of gestation.

Vaginal compared with intramuscular progestogen for preventing preterm birth in high-risk pregnant women (VICTORIA study): a multicentre, open-label randomised trial and meta-analysis

OBJECTIVE

To compare the efficacy of two types of progestogen therapy for preventing preterm birth (PTB) and to review the relevant literature.

DESIGN

A multicentre, randomised, open-label, equivalence trial and a meta-analysis.

SETTING

Tertiary referral hospitals in South Korea.

POPULATION

Pregnant women with a history of spontaneous PTB or short cervical length (<25 mm).

METHODS

Eligible women were screened and randomised at 16-22 weeks of gestation to receive either 200 mg of vaginal micronised progesterone daily (vaginal group) or an intramuscular injection of 250 mg 17α-hydroxyprogesterone caproate weekly (IM group). Stratified randomisation was carried out according to participating centres and indications for progestogen therapy. This trial was registered at ClinicalTrials.gov (NCT02304237).

MAIN OUTCOME MEASURE

Preterm birth (PTB) before 37 weeks of gestation.

RESULTS

A total of 266 women were randomly assigned and a total of 247 women (119 and 128 women in the vaginal and IM groups, respectively) were available for the intention-to-treat analysis. Risks of PTB before 37 weeks of gestation did not significantly differ between the two groups (22.7 versus 25.8%, P = 0.571). The difference in PTB risk between the two groups was 3.1% (95% CI -7.6 to 13.8%), which was within the equivalence margin of 15%. The meta-analysis results showed no significant differences in the risk of PTB between the vaginal and IM progestogen treatments.

CONCLUSION

Compared with vaginal progesterone, treatment with intramuscular progestin might increase the risk of PTB before 37 weeks of gestation by as much as 13.8%, or reduce the risk by as much as 7.6%, in women with a history of spontaneous PTB or with short cervical length.

TWEETABLE ABSTRACT

Vaginal and intramuscular progestogen showed equivalent efficacy for preventing preterm birth before 37 weeks of gestation.

The use of progesterone during pregnancy to prevent preterm birth

One of the most significant problems facing maternal and children health worldwide is preterm birth (PTB). Although strategies to increase the survival of premature infants have significantly improved in the past few decades, they have yet to be successful. Nine years ago, the use of progesterone in pregnancy was approved by the United States Food and Drug Administration (FDA) for PTB prevention. This paper reviews the recent evidence supporting the use of progesterone in pregnancy for PTB prevention and provides guidelines for its use in daily clinical practice. The guidelines address multiple current controversial areas regarding the prevention of PTB to aid physicians with their clinical decision-making practice, including the use in multifetal gestation, different formulations, safety in pregnancy, dose and route of administration.Saudi Med J 2020; Vol. 41 (4): 333-340doi: 10.15537/smj.2020.4.25036How to cite this article:Alsulmi ES, Alfaraj M, Faden Y, Al Qahtani N. The use of progesterone during pregnancy to prevent preterm birth. Saudi Med J 2020; Vol. 41: 333-340. doi: 10.15537/smj.2020.4.25036.

Cervical elastography using E-cervix for prediction of preterm birth in singleton pregnancies with threatened preterm labor

Objective: E-Cervix™ (WS80A; Samsung, Seoul, Korea) elastography is a recent quantification tool to measure the stiffness of the cervix using strain elastography. The aim of this study was to evaluate the prediction performance of E-cervix for preterm birth in singleton gestation with threatened preterm labor (PTL).Methods: This was a cohort study of singleton pregnancies without prior preterm birth presenting to obstetrics triage for threatened PTL between 23 0/7 and 33 6/7 week who received screening for PTL with transvaginal ultrasound cervical length (TVU CL) and cervical elastography with E-cervix at the time of triage. Cervical elastography parameters were examined and compared between women who delivered preterm and those who did not. The quantification of cervical strain was calculated by a data analysis system that directly analyses raw data from the region of interest (ROI) and described as hardness ratio (HR), mean strain level within 1 cm from internal os (IOS) and external os (EOS).Results: Ninety-five singleton pregnancies without prior preterm birth and with threatened PTL between 23 0/7 and 33 6/7 week of gestation were included in the study. Forty-two (44.2%) had cervical length <25 mm, and were admitted for true PLT. Out of the 53 women with cervical length ≥25 mm, 40 (75.5%) were discharged, and 13 (24.5%) were admitted. Women with threatened PTL but without true PTL, had significantly higher HR compared to those with true PTL (49.0 ± 20.9% versus 34.8 ± 19.6%; p < .01), and significantly lower stiffness of cervical IOS and EOS. Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm, in overall cohort, and in the subset of only women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01).Conclusions: Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL. Women with low HR, especially with HR less than 50 or 35%, are at increased risk of PTB.Condensation: Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm and significantly lower IOS and EOS, in overall cohort, and in the subset of women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01).Key message: Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL.

Vaginal lactoferrin in prevention of preterm birth in women with bacterial vaginosis

Objective: To evaluate use of vaginal lactoferrin in prevention of preterm birth (PTB) in women with first trimester bacterial vaginosis and prior spontaneous PTB.Methods: This is a retrospective cohort study of all consecutive singleton gestations with prior PTB, and first trimester diagnosis of bacterial vaginosis. Women who were found to have bacterial vaginosis were recommended lactoferrin 300 mg vaginal tablets daily for 21 days. The primary outcome was the incidence of PTB at less than 37 weeks of gestations. Outcomes were compared in women who received daily lactoferrin with those who did notResults: During the study period, 847 pregnant women with prior spontaneous PTB were screened for bacterial vaginosis. Of them, 193 were found to have bacterial vaginosis in the first trimester, with an overall incidence of 22.8%. Out of the 193 women, 125 met the inclusion criteria for the study and were analyzed. Sixty of the included women received vaginal lactoferrin, while 65 did not. Women who received supplementation with lactoferrin had a significantly lower rate of PTB < 37 weeks (25.0 versus 44.6%; p = .02), lower mean gestational age at delivery (37.7 ± 3.2 versus 35.9 ± 4.1 weeks; p = .01), and lower rate of admission for threatened PTL (45.0 versus 70.8%; p = .04). No between-group differences were noticed in the other outcomes, including chorioamnionitis, PPROM < 34 weeks, and neonatal outcomes. No cases of late miscarriage were reported in our cohort. No cases of adverse events were reported.Conclusion: Based on this small single-center retrospective study, supplementation with vaginal lactoferrin in women with first trimester bacterial vaginosis may be an option to reduce the risk of preterm delivery.

The Role Of Progestogens In Threatened And Idiopathic Recurrent Miscarriage

It is well known that progesterone plays a major role in the maintenance of pregnancy, particularly during the early stages, as it is responsible for preparing the endometrium for implantation and maintenance of the gestational sac. The management of pregnant women at risk of a threatened or idiopathic recurrent miscarriage is complex and critical. Therefore, a group of obstetricians and gynecologists practicing in Saudi Arabia gathered to update the 2014 Saudi guidelines for threatened and recurrent miscarriage management. In preparation, a literature review was conducted to explore the role of oral, vaginal, and injectable progestogens: this was used as a basis to develop position statements to guide and standardize practice across Saudi Arabia.

Effects of home visits for pregnant and postpartum women on premature birth, low birth weight and rapid repeat birth: a meta-analysis and systematic review of randomized controlled trials

BACKGROUND

Home visits seem promising for improving the health of women and infants during pregnancy and postpartum. This review aimed to quantitatively analyse the effects of home visits delivered during pregnancy and postpartum on premature birth (PTB), low birth weight (LBW) and rapid repeat birth (RRB).

METHODS

Literature was retrieved from PubMed, EMBASE, Web of Science and the Cochrane Library from January 1960 to October 2018 and the references lists of related studies and reviews were also screened. Eligible papers were randomized controlled trials (RCTs) that focussed on home visits conducted with women during pregnancy or postpartum and reported at least one of the following results: PTB, LBW and RRB. Fixed- or random-effects models were used to analyse the pooled results.

RESULTS

Fourteen RCTs were included. Pooled estimates showed a beneficial effect on LBW (odds ratio (OR) = 0.83; P = 0.03; low-quality evidence) and RRB in the professional-visit subgroup (OR = 0.62; P = 0.003; moderate-quality evidence). However, there was insufficient evidence to support the favourable effects of home visits on PTB (OR = 0.96; P = 0.59, moderate-quality evidence) and RRB in the non-professional-visit subgroup (OR = 0.86; P = 0.53, moderate-quality evidence). The overall methodological quality was moderate. Egger's test suggested no publication bias for PTB and LBW.

CONCLUSION

This meta-analysis is the first to suggest that home visits can prevent and decrease LBW and RRB; however, it remains unclear whether home visits benefit PTB. Therefore, home visits can be an alternative and complementary part of primary health care for women, especially those with risk factors.

Pharmacokinetics of vaginal progesterone in pregnancy

BACKGROUND

Characterization of pharmacokinetics is lacking for vaginal progesterone in pregnancy. Dosing of vaginal progesterone for preterm birth prevention has been empirical. Owing to pregnancy-related changes in vaginal and uterine blood flow, hepatic metabolism, renal clearance, and endogenously elevated serum progesterone, studies outside of pregnancy may not be applicable. The lack of the pharmacokinetics profile of vaginally administered progesterone in pregnancy limits the ability to define the exposure-response relationship needed to optimize dosing, which has implications for its use in research and clinical care regarding management of short cervix, prevention of recurrent preterm birth, and prevention of recurrent miscarriage.

OBJECTIVE

This was a study to establish the feasibility of using serum progesterone to establish basic pharmacokinetic parameters of vaginal progesterone in pregnancy for preterm birth prevention.

STUDY DESIGN

This is a prospective study of 6 low-risk singletons at 18 0/7 to 23 6/7 weeks' gestation with body mass index 20-40. Exclusion criteria were current vaginitis, abnormal Pap smear, prescription medication use, cervical length ≤25 mm, prior preterm birth, and contraindication to progesterone. Participants received a single dose of 200 mg micronized vaginal progesterone and serum progesterone levels were evaluated every 2 hours from 0 to 12 hours and then 24 hours post dose. Primary outcome was concentration/time profile of serum progesterone.

RESULTS

Median (range) maternal age was 27 (21.5-33.3) years, median body mass index was 26.5 (23.3-29.0) kg/m², and median gestational age was 22.9 (21.0-23.4) weeks. Median baseline serum progesterone was 47 (40-52) ng/mL, median peak concentration was 54 (48-68) ng/mL, and median time to peak was 12 (4-15) hours. There was a trend in rising serum progesterone over baseline with a median change in peak concentration of 11 ng/mL and interquartile range of 2-22. Median percent change from baseline was an increase by 24% (interquartile range, 4%-53%). However, there was no clear elimination phase and the median area under the curve was 112 ng*h/mL with an interquartile range of -43 to 239.

CONCLUSION

Unlike in nonpregnant individuals, administration of vaginal progesterone in pregnant individuals only minimally impacts systemic exposure. There is a limited trend of rising serum progesterone over baseline levels, with significant inter-individual variability. Serum progesterone is unlikely to be a good candidate for establishing pharmacokinetics or dosing of vaginal progesterone in pregnancy for preterm birth prevention.

Progesterone for the Prevention of Preterm Birth - an Update of Evidence-Based Indications

The prevention and treatment of preterm birth remains one of the biggest challenges in obstetrics. Worldwide, 11% of all children are born prematurely with far-reaching consequences for the children concerned, their families and the health system. Experimental studies suggest that progesterone inhibits uterine contractions, stabilises the cervix and has immunomodulatory effects. Recent years have seen the publication of numerous clinical trials using progestogens for the prevention of preterm birth. As a result of different inclusion criteria and the use of different progestogens and their methods of administration, it is difficult to draw comparisons between these studies. A critical evaluation of the available studies was therefore carried out on the basis of a search of the literature (1956 to 09/2018). Taking into account the most recent randomised, controlled studies, the following evidence-based recommendations emerge: In asymptomatic women with singleton pregnancies and a short cervical length on ultrasound of ≤ 25 mm before 24 weeks of gestation (WG), daily administration of vaginal progesterone (200 mg capsule or 90 mg gel) up until 36 + 6 WG leads to a significant reduction in the preterm birth rate and an improvement in neonatal outcome. The latest data also suggest positive effects of treatment with progesterone in cases of twin pregnancies with a short cervical length on ultrasound of ≤ 25 mm before 24 WG. The study data for the administration of progesterone in women with singleton pregnancies with a previous preterm birth have become much more heterogeneous, however. It is not possible to make a general recommendation for this indication at present, and decisions must therefore be made on a case-by-case basis. Even if progesterone use is considered to be safe in terms of possible long-term consequences, exposure should be avoided where it is not indicated. Careful patient selection is crucial for the success of treatment.

Steroid hormones and pregnancy

Pregnancy is associated with physiological adjustments in order to allow adequate growth and fetal development. In particular, steroids are necessary to maintain in balance numerous functions during gestation. Steroidogenesis in the maternal, placental and fetal compartments and the biological effects of progestins and estrogens that play a pivotal role before and during pregnancy are described. Although it is well-known that androgens are considered as substrate for estrogens biosynthesis, their biosynthesis and functionality in placental and other tissues have been questioned. As compared with healthy pregnancy, steroid hormones levels have been found altered in complicated pregnancies and hormonal treatments have been used is some pathologies. Therefore, the aim of this work was to review the biosynthesis, function and regulation of progestins, androgens and estrogens during gestation. Furthermore, steroid hormones concentrations during healthy and complicated pregnancy as well hormonal therapies for the prevention of miscarriages and preterm deliveries are discussed in the present review.

Oral progesterone for the prevention of recurrent preterm birth: systematic review and metaanalysis

OBJECTIVE DATA

The purpose of this study was to perform a systematic review and metaanalysis of randomized controlled trials on oral progesterone compared with placebo or other interventions for preterm birth prevention in singleton pregnancies with previous spontaneous preterm birth. The primary outcome was preterm birth at <37 weeks gestation; the secondary outcomes included preterm birth rate at <34 weeks gestation, neonatal morbidity/death, and maternal side-effects.

STUDY

Searches were performed in PubMed, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, and the Cochrane Register with the use of a combination of words related to "preterm birth," "preterm delivery," "progesterone," "progestogens," and "oral" from inception of each database to April 2018. Additionally, systematic reviews on progesterone for preterm birth prevention that were identified in our search were also reviewed for additional studies. We included all randomized trials of asymptomatic singleton gestations with previous spontaneous singleton preterm birth that had been randomized to prophylactic treatment with oral progesterone vs placebo, no treatment, or other preterm birth intervention. Exclusion criteria included quasirandomized trials, trials that involved women with preterm labor/membrane rupture at the time of randomization or multiple gestations.

STUDY APPRAISAL AND SYNTHESIS METHODS

The risk of bias and quality of evidence were assessed for each study. All analyses were done with an intention-to-treat approach. The primary outcome was incidence of preterm birth at <37 weeks gestation; the secondary outcomes included preterm birth at <34 and <28 weeks gestation, maternal adverse events, maternal serum progesterone level, and neonatal morbidity and death. Summary measures were reported as relative risk or mean difference. I² >30% was used to identify heterogeneity.

RESULTS

The search strategy identified 79 distinct studies. Three trials on oral progesterone vs placebo (involved 386 patients: 196 in oral progesterone and 190 in placebo) met the inclusion criteria; there were no studies on oral progesterone vs other intervention that met inclusion criteria. Metaanalysis demonstrated a significantly decreased risk of preterm birth at <37 weeks gestation (42% vs 63%; P=.0005; relative risk, 0.68; 95% confidence interval, 0.55-0.84), preterm birth at <34 weeks gestation (29% vs 53%; P<.00001; relative risk, 0.55; 95% confidence interval, 0.43-0.71), and increased gestational age of delivery (mean difference, 1.71 weeks; 95% confidence interval, 1.11-2.30) with oral progesterone compared with placebo. There was a significantly lower rate of perinatal death (5% vs 17%; P=.001; relative risk 0.32; 95% confidence interval, 0.16-0.63), neonatal intensive care admission (relative risk, 0.39; 95% confidence interval, 0.25-0.61), respiratory distress syndrome (relative risk, 0.21; 95% confidence interval, 0.05-0.93), and higher birthweight (mean difference, 435.06 g; 95% confidence interval, 324.59-545.52) with oral progesterone. There was a higher rate of maternal adverse effects with oral progesterone that included dizziness (relative risk, 2.95; 95% confidence interval, 1.47-5.90), somnolence (relative risk, 2.06; 95% confidence interval, 1.29-3.30), and vaginal dryness (relative risk, 2.37; 95% confidence interval, 1.10-5.11); no serious adverse effects were noted.

CONCLUSION

Oral progesterone appears to be effective for the prevention of recurrent preterm birth and a reduction in perinatal morbidity and mortality rates in asymptomatic singleton gestations with a history of previous spontaneous preterm birth compared with placebo. There were also increased adverse effects with oral progesterone therapy compared with placebo, although none were serious. Further randomized study on oral progesterone compared with other established therapies for the prevention of recurrent preterm birth are warranted.

Primary and secondary prevention of preterm birth: a review of systematic reviews and ongoing randomized controlled trials

BACKGROUND

Preterm birth (PTB) is a leading cause of perinatal morbidity and mortality. Interventions aimed at preventing PTB can be classified as primary, secondary, or tertiary prevention.

OBJECTIVE

To conduct a review of systematic reviews on the effectiveness and safety of primary and secondary preterm birth prevention interventions.

SEARCH STRATEGY

A systematic literature search of the Cochrane, PubMed/Medline, EMBASE and CINAHL databases was conducted on 2 September 2015, and updated on 21 November 2016.

SELECTION CRITERIA

We included any published systematic review of randomized controlled trials (RCTs) or individual patient data (IPD) of RCTs related to primary or secondary prevention of PTB, published between 2005-2016 where gestational age at birth (of any interval) was a pre-specified outcome. Individual trials and non-systematic reviews were not eligible.

DATA COLLECTION AND ANALYSIS

The population of interest was all pregnant women, regardless of PTB risk. The primary outcome was PTB < 37 weeks.

MAIN RESULTS

In total, 112 reviews were included in this study. Overall there were 49 Cochrane and 63 non-Cochrane reviews. Eight were individual participant data (IPD) reviews. Sixty reviews assessed the effect of primary prevention interventions on risk of PTB. Positive effects were reported for lifestyle and behavioural changes (including diet and exercise); nutritional supplements (including calcium and zinc supplementation); nutritional education; screening for lower genital tract infections. Eighty-three systematic reviews were identified relating to secondary PTB prevention interventions. Positive effects were found for low dose aspirin among women at risk of preeclampsia; clindamycin for treatment of bacterial vaginosis; treatment of vaginal candidiasis; progesterone in women with prior spontaneous PTB and in those with short midtrimester cervical length; L-arginine in women at risk for preeclampsia; levothyroxine among women with tyroid disease; calcium supplementation in women at risk of hypertensive disorders; smoking cessation; cervical length screening in women with history of PTB with placement of cerclage in those with short cervix; cervical pessary in singleton gestations with short cervix; and treatment of periodontal disease.

CONCLUSION

The overview serves as a guide to current evidence relevant to PTB prevention. Only a few interventions have been demononstrated to be effective, including cerclage, progesterone, low dose aspirin, and lifestyle and behavioural changes. For several of the interventions evaluated, there was insufficient evidence to assess whether they were effective or not.

Effects of progestogens in women with preterm premature rupture of membranes

Different strategies have been adopted for prevention of spontaneous preterm birth, including use of progestogens. So far, five randomized trials have been published evaluating the efficacy of progestogens in women with PPROM, including a total of 425 participants. All the five trials enrolled pregnant women with singleton pregnancies randomized between 20 and 34 weeks of gestation. In four trials women were randomized to either weekly intramuscular 250 mg 17α-hydroxyprogesterone-caproate or placebo, while Mirzaei et al. was a three arms trials in which women received weekly intramuscular 250 mg 17α-hydroxyprogesterone-caproate, or rectal progesterone 400 mg daily, or no treatment. In all the trials, latency antibiotics were used, and tocolysis was used permitted for first 48 hours at discretion of attending physician. Recently a meta-analysis including the five trials has been published. They found that when compared to placebo weekly intramuscular 250 mg 17α-hydroxyprogesterone-caproate did not alter the latency period to delivery in singleton gestations with PPROM. Additionally, there was no difference in gestational age at delivery between groups or in mode of delivery. No significant differences were reported in maternal or neonatal outcomes, with latency not significantly altered in sensitivity analyses. So far, no trials have been published evaluating natural vaginal progesterone in women with PPROM.

Progestogens in singleton gestations with preterm prelabor rupture of membranes: a systematic review and metaanalysis of randomized controlled trials

OBJECTIVE DATA

Preterm prelabor rupture of membranes occurs in 3% of all pregnancies. Neonatal benefit is seen in uninfected women who do not deliver immediately after preterm prelabor rupture of membranes. The purpose of this study was to evaluate whether the administration of progestogens in singleton pregnancies prolongs pregnancy after preterm prelabor rupture of membranes.

STUDY

Searches were performed in MEDLINE, OVID, Scopus, EMBASE, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials with the use of a combination of keywords and text words related to "progesterone," "progestogen," "prematurity," and "preterm premature rupture of membranes" from the inception of the databases until January 2018. We included all randomized controlled trials of singleton gestations after preterm prelabor rupture of membranes that were randomized to either progestogens or control (either placebo or no treatment). Exclusion criteria were trials that included women who had contraindications to expectant management after preterm prelabor rupture of membranes (ie, chorioamnionitis, severe preeclampsia, and nonreassuring fetal status) and trials on multiple gestations. We planned to include all progestogens, including but not limited to 17-α hydroxyprogesterone caproate, and natural progesterone.

STUDY APPRAISAL AND SYNTHESIS METHODS

The primary outcome was latency from randomization to delivery. Metaanalysis was performed with the use of the random effects model of DerSimonian and Laird to produce relative risk with 95% confidence interval. Analysis was performed for each mode of progestogen administration separately.

RESULTS

Six randomized controlled trials (n=545 participants) were included. Four of the included trials assessed the efficacy of 17-α hydroxyprogesterone caproate; 1 trial assessed rectal progestogen, and 1 trial had 3 arms that compared 17-α hydroxyprogesterone caproate, rectal progestogen, and placebo. The mean gestational age at time randomization was 26.9 weeks in the 17-α hydroxyprogesterone caproate group and 27.3 weeks in the control group. 17-α Hydroxyprogesterone caproate administration was not found to prolong the latency period between randomization and delivery (mean difference, 0.11 days; 95% confidence interval, -3.30 to 3.53). There were no differences in mean gestational age at delivery, mode of delivery, or maternal or neonatal outcomes between the 2 groups. Similarly, there was no difference in latency for those women who received rectal progesterone (mean difference, 4.00 days; 95% confidence interval, -0.72 to 8.72).

CONCLUSION

Progestogen administration does not prolong pregnancy in singleton gestations with preterm prelabor rupture of membranes.

Effects of exercise during pregnancy in women with short cervix: Secondary analysis from the Italian Pessary Trial in singletons

OBJECTIVE

To evaluate effects of exercise during pregnancy in asymptomatic singleton pregnancies without prior spontaneous preterm birth (SPTB) but with short transvaginal ultrasound cervical length (TVU CL).

STUDY DESIGN

This is a secondary analysis of the Italian Pessary Trial for the Italian Preterm Birth Prevention (IPP) Working Group. In the original prospective randomized controlled trial asymptomatic singleton pregnancies without prior SPTB but with TVU CL ≤ 25 mm at 18 0/6-23 6/7 weeks were randomized into 1:1 ratio to either cervical pessary or no pessary. During their follow-up visits, women were asked about their activity. For the purpose of this secondary analysis, women were classified in the following groups, using the information obtained in the follow-up visit one month after randomization: 1) Exercise group, defined as women performing exercise ≥2 days a week for ≥20 min each day. 2) No exercise group, defined as women performing exercise <2 days a week for ≥20 min each day. The primary outcome of this secondary analysis was PTB < 37 weeks.

RESULTS

300 women were included in this analysis. 99 (33.0%) were included in the exercise group. 201 (67.0%) were included in the no exercise group. Of the 201 women in the no exercise group, 90 (44.8%) affirmed that they had reduced their activity after the diagnosis of short cervix despite the research staff recommendations, while the other 111 (55.2%) women performed a sedentary life style even before the diagnosis of short cervix. PTB < 37 weeks occurred in 22 women (22.2%) in the exercise group, and 66 women (32.8%) in the no exercise group (aOR 0.65, 95% CI 0.33-1.03).

CONCLUSION

In asymptomatic singleton pregnancies with short cervix, performing exercise ≥2 days a week for ≥20 min each day does not increase the risk of PTB but is indeed associated with a non-significant reduction in PTB < 37 weeks by 32%.

Midtrimester transvaginal ultrasound cervical length screening for spontaneous preterm birth in diamniotic twin pregnancies according to chorionicity

OBJECTIVE

To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester screening for spontaneous preterm birth in asymptomatic monochorionic diamniotic versus dichorionic diamniotic twin pregnancies STUDY DESIGN: This was a multicenter retrospective cohort study. Study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7-23 6/7 weeks gestation. We excluded women that received progesterone, pessary, or cerclage. Distribution of CL was determined and normality was examined. Mean of TVU CL were compared between monochorionic diamniotic and dichorionic diamniotic pregnancies. The relationship of TVU CL with gestational age (GA) at delivery and incidence of spontaneous preterm birth (SPTB) at different TVU CL cut offs were assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups.

RESULTS

580 women with diamniotic twin pregnancies underwent TVU CL screening between 18 0/6 and 23 6/7 weeks. 175 (30.2%) were monochorionic diamniotic pregnancies, and 405 (69.8%) were dichorionic pregnancies. The demographic characteristics were similar on both groups. The mean GA at TVU CL was about 20 week in both groups. The mean TVU CL was significantly lower in the monochorionic diamniotic (32.8 ± 10.1) compared to the dichorionic (34.9 ± 8.6) group (MD -2.10 mm, 95% CI -3.91 to -0.29). TVU CL ≤30 mm was 16.6% (29/175) in the monochorionic group, and 11.9% (48/405) in the dichorionic group (aOR 1.48, 95% CI 1.03-2.43). Twins with a monochorionic diamniotic pregnancy had a significantly higher incidence of SPTB (53.1% vs 44.9%; aOR 1.22, 95% CI 1.22-1.79). For any given CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for monochorionic diamniotic pregnancies was about 2 weeks earlier compared to dichorionic pregnancies (MD -2.1 weeks; ANCOVA P < 0.001).

CONCLUSION

Monochorionic diamniotic twin pregnancies had a higher rate of spontaneous preterm birth than dichorionic diamniotic pregnancies. The higher rate of spontaneous preterm delivery in monochorionic pregnancies is associated with lower midtrimester TVU CL when compared to dichorionic pregnancies.

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.

Progestogens and pregnancy loss

Progestational agents are often prescribed to prevent pregnancy loss. Progestogens affect implantation, cytokine balance, natural killer cell activity, arachidonic acid release and myometrial contractility. Progestogens have therefore been used at all stages of pregnancy including luteal-phase support prior to pregnancy, threatened miscarriage, recurrent miscarriage, and to prevent preterm labor. In luteal support, a Cochrane review reported that progestogens were associated with a higher rate of live births or ongoing pregnancy in the progesterone group (odds ratio 1.77, 95% confidence interval (CI) 1.09-2.86). Evidence suggests that progestogens are also effective for treating threatened miscarriage. Again, in a Cochrane Database review, progestogens were associated with a reduced odds ratio of 0.53 (95% CI 0.35-0.79) when progestogens were used. In recurrent miscarriage, progestogens also seem to have a beneficial effect. A meta-analysis of progestational agents showed a 28% increase in the live birth rate (relative risk 0.72, 95% CI 0.53-0.97). For the last 30 years, progestogens have been used to prevent preterm labor. Recent meta-analyses also report beneficial effects. This review summarizes the literature and the author's experience using progestogens to prevent pregnancy loss.

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.

Progesterone improves perinatal neuromotor outcomes in a mouse model of intrauterine inflammation via immunomodulation of the placenta

To assess the fetal neuroprotective potential of progesterone using a well-validated mouse model of lipopolysaccharide (LPS)-induced intrauterine inflammation (IUI). Embryonic day 17 pregnant mouse dams (n = 69) were randomly allocated to receive 17-hydroxyprogesterone caproate (17-OHPC), micronized progesterone (MP), or vehicle 1 hour prior to intrauterine injection of phosphate-buffered saline (PBS) or LPS. After 6 hours, mice were killed for the collection of placentas and fetal brains, or pregnancy continued for the evaluation of preterm birth (PTB) and offspring neuromotor function. Placentas and fetal brains were analyzed by mini-mRNA array for 96 immune markers with individual confirmatory qPCR. Progesterone pre-treatment before LPS-induced IUI improved neuromotor tests in offspring at PND5 compared to no pre-treatment (P < .05). In placentas, 17-OHPC, but not MP, significantly reduced CXCL9 (P < .05) with a trend toward a lower level of CXCL10. In fetal brains, 17-OHPC significantly reduced CXCL9 compared to no pre-treatment (P < .05) and IL-1β compared to pre-treatment with MP (P < .01). Progesterone pre-treatment prior to LPS-induced IUI improved offspring neuromotor outcomes. 17-OHPC, but not MP, resulted in greater immunomodulation of T cell-mediated immunity in placenta and fetal brain, suggesting a possible mechanism for the observed neuroprotective effects.

Effect of Cervical Pessary on Spontaneous Preterm Birth in Women With Singleton Pregnancies and Short Cervical Length: A Randomized Clinical Trial

IMPORTANCE

Spontaneous preterm birth is a major cause of perinatal morbidity and mortality. It is unclear if a cervical pessary can reduce the risk of spontaneous preterm delivery.

OBJECTIVE

To test whether in asymptomatic women with singleton pregnancies and no prior spontaneous preterm birth but with short cervical length on transvaginal ultrasound, use of a cervical pessary would reduce the rate of spontaneous preterm birth at less than 34 weeks of gestation.

DESIGN, SETTING, AND PARTICIPANTS

Parallel-group, nonblinded, randomized clinical trial conducted from March 1, 2016, to May 25, 2017, at a single center in Italy. Asymptomatic women with singleton gestations, no previous spontaneous preterm births, and cervical lengths of 25 mm or less at 18 weeks 0 days to 23 weeks 6 days of gestation were eligible.

INTERVENTIONS

Patients were randomized 1:1 to receive either cervical pessary (n = 150) or no pessary (n = 150). The pessary was removed between 37 weeks 0 days and 37 weeks 6 days of gestation or earlier if clinically indicated. The control group received standard care. For cervical length of 20 mm or shorter, women in both groups were prescribed vaginal progesterone, 200 mg/d, until 36 weeks 6 days of gestation. No bed rest or activity restriction was recommended.

MAIN OUTCOMES AND MEASURES

The primary end point was spontaneous preterm birth at less than 34 weeks of gestation. Secondary outcomes were adverse events.

RESULTS

Among 300 women who were randomized (mean age, 29 [SD, 6.3] years; mean gestational age, 22 [SD, 1.3] weeks), 100% completed the trial. The primary end point occurred in 11 women (7.3%) in the pessary group and 23 women (15.3%) in the control group (between-group difference, -8.0% [95% CI, -15.7% to -0.4]; relative risk, 0.48 [95% CI, 0.24-0.95]). During follow-up, the pessary group had a higher rate of increased or new vaginal discharge (86.7% vs 46.0%; between-group difference, +40.7% [95% CI, +30.1%-+50.3%]; relative risk, 1.88 [95% CI, 1.57-2.27]).

CONCLUSIONS AND RELEVANCE

Among women without prior spontaneous preterm birth who had asymptomatic singleton pregnancies and short transvaginal cervical length, use of a cervical pessary, compared with no pessary use, resulted in a lower rate of spontaneous preterm birth at less than 34 weeks of gestation. The results of this single-center, nonblinded study among selected pregnant women require confirmation in multicenter clinical trials.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02716909.

The Influence of Oral Dydrogesterone and Vaginal Progesterone on Threatened Abortion: A Systematic Review and Meta-Analysis

Objective

To conduct systematic analyses to evaluate the efficacy of progesterone therapy for the prevention of miscarriages in pregnant women experiencing threatened abortion.

Methods

In November 2016, we performed a systematic literature search and identified 51 articles in PubMed, Embase, and Cochrane databases. We identified nine randomized trials that included 913 pregnant women (including 322 treated with oral dydrogesterone, 213 treated with vaginal progesterone, and 378 control subjects) who met the selection criteria.

Results

The incidence of miscarriage was significantly lower in the total progesterone group than in the control group (13.0% versus 21.7%; odds ratio, 0.53; 95% confidence interval (CI), 0.36 to 0.78; P = 0.001; I², 0%). Moreover, the incidence of miscarriage was significantly lower in the oral dydrogesterone group than in the control group (11.7% versus 22.6%; odds ratio, 0.43; 95% CI, 0.26 to 0.71; P = 0.001; I², 0%) and was lower in the vaginal progesterone group than in the control group, although this difference was nonsignificant (15.4% versus 20.3%; odds ratio, 0.72; 95% CI, 0.39 to 1.34; P = 0.30; I², 0%). However, the incidence of miscarriage was not different between the oral dydrogesterone and vaginal progesterone groups.

Conclusion

Progesterone therapy, especially oral dydrogesterone, can effectively prevent miscarriage in pregnant women experiencing threatened abortion.

In an in-vitro model using human fetal membranes, 17-α hydroxyprogesterone caproate is not an optimal progestogen for inhibition of fetal membrane weakening

BACKGROUND

The progestogen 17-α hydroxyprogesterone caproate (17-OHPC) is 1 of only 2 agents recommended for clinical use in the prevention of spontaneous preterm delivery, and studies of its efficacy have been conflicting. We have developed an in-vitro model to study the fetal membrane weakening process that leads to rupture in preterm premature rupture of the fetal membranes (pPROM). Inflammation/infection associated with tumor necrosis factor-α (TNF-α) induction and decidual bleeding/abruption associated thrombin release are leading causes of preterm premature rupture of the fetal membranes. Both agents (TNF-α and thrombin) cause fetal membrane weakening in the model system. Furthermore, granulocyte-macrophage colony-stimulating factor (GM-CSF) is a critical intermediate for both TNF-α and thrombin-induced fetal membrane weakening. In a previous report, we demonstrated that 3 progestogens, progesterone, 17-alpha hydroxyprogesterone (17-OHP), and medroxyprogesterone acetate (MPA), each inhibit both TNF-α- and thrombin-induced fetal membrane weakening at 2 distinct points of the fetal membrane weakening pathway. Each block both the production of and the downstream action of the critical intermediate granulocyte-macrophage colony-stimulating factor.

OBJECTIVE

The objective of the study was to characterize the inhibitory effects of 17-OHPC on TNF-α- and thrombin-induced fetal membrane weakening in vitro.

STUDY DESIGN

Full-thickness human fetal membrane fragments from uncomplicated term repeat cesarean deliveries were mounted in 2.5 cm Transwell inserts and cultured with/without 17-alpha hydroxyprogesterone caproate (10^-9 to 10^-7 M). After 24 hours, medium (supernatant) was removed and replaced with/without the addition of tumor necrosis factor-alpha (20 ng/mL) or thrombin (10 U/mL) or granulocyte-macrophage colony-stimulating factor (200 ng/mL). After 48 hours of culture, medium from the maternal side compartment of the model was assayed for granulocyte-macrophage colony-stimulating factor and the fetal membrane fragments were rupture strength tested.

RESULTS

Tumor necrosis factor-alpha and thrombin both weakened fetal membranes (43% and 62%, respectively) and increased granulocyte-macrophage colony-stimulating factor levels (3.7- and 5.9-fold, respectively). Pretreatment with 17-alpha hydroxyprogesterone caproate inhibited both tumor necrosis factor-alpha- and thrombin-induced fetal membrane weakening and concomitantly inhibited the induced increase in granulocyte-macrophage colony-stimulating factor in a concentration-dependent manner. However, contrary to our prior reports regarding progesterone and other progestogens, 17-alpha hydroxyprogesterone caproate did not also inhibit granulocyte-macrophage colony-stimulating factor-induced fetal membrane weakening.

CONCLUSION

17-Alpha hydroxyprogesterone caproate blocks tumor necrosis factor-alpha- and thrombin-induced fetal membrane weakening by inhibiting the production of granulocyte-macrophage colony-stimulating factor. However, 17-alpha hydroxyprogesterone caproate did not also inhibit granulocyte-macrophage colony-stimulating factor-induced weakening. We speculate that progestogens other than 17-alpha hydroxyprogesterone caproate may be more efficacious in preventing preterm premature rupture of the fetal membranes-related spontaneous preterm birth.

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.