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

Multi-parametric quantitative evaluation of murine cervical remodeling during pregnancy and postpartum

Cervical remodeling during pregnancy is a critical process that, if untimely, can lead to complications such as preterm birth (PTB). This study introduces a novel multi-parametric approach combining non-invasive imaging modalities to quantify cervical tissue changes during pregnancy and postpartum in a murine model. By integrating ultrasound-based measurements of cervical length, photoacoustic imaging of the collagen-to-water ratio, and elastography for tissue elasticity alongside histological assessments, this method provides a comprehensive evaluation of cervical remodeling. The findings reveal that combining these parameters significantly improves the accuracy of gestational age prediction compared to individual measurements, with a tri-parametric model achieving 85.3% prediction accuracy compared to 65.4% accuracy with histological analysis alone. This approach not only enhances the understanding of cervical remodeling but also holds potential as a minimally invasive, point-of-care diagnostic tool for early detection of cervical ripening and PTB risk. Ultimately, these advancements could inform clinical strategies for pregnancy management and labor induction, improving maternal and neonatal outcomes.

Knowledge mapping for prediction of spontaneous preterm birth

INTRODUCTION

Preterm birth (PTB) before 37 weeks gestation, especially spontaneous premature birth (sPTB), poses significant global health challenges, with rising rates linked to advanced and multiple pregnancies. Despite efforts to understand the pathogenesis and related biomarkers of sPTB, accurate prediction is still difficult to achieve. Recent research in academic journals has focused on sPTB prediction, prompting our bibliometric analysis to understand the current situation and explore the new research direction.

METHODS

We used keywords in the Web of Science Core Collection (WoSCC) to search for articles related to sPTB prediction from 2004 to 2023. Subsequently, we primarily employed three distinct software tools (VOSviewer, CiteSpace, and Python) for conducting this bibliometric analysis.

RESULTS

Focusing on sPTB as the primary subject, a total of 647 papers have been published in 136 academic journals. There are the most publications from The United States (n = 245, 39.26 %), and the University of London contributed the most publications (n = 57, 8.81 %). The American Journal of Obstetrics and Gynecology is the most productive academic journal on sPTB prediction [n = 74, 11.44 %; impact factor (IF) = 8.7]. Through the co-occurrence and cluster analysis, we found that recent research has focused on is "pamg-1", "uterocervical angle", "twin pregnancy", "quantitative ultrasound", and "lactobacillus iners".

CONCLUSION

We utilized bibliometric software to perform a comprehensive analysis of the literature concerning sPTB prediction. Broadly, the primary focus of future sPTB prediction lies in the application of novel ultrasound and biological markers, as well as in predicting sPTB in twin pregnancies.

Cerclage in singleton pregnancies with no prior spontaneous preterm birth and short cervix: a randomized controlled trial

BACKGROUND

Preterm birth remains a leading cause of neonatal morbidity and mortality. Cerclage for short cervical length ≤25 mm in patients with singleton pregnancies with a history of spontaneous preterm birth is associated with decreased neonatal morbidity/mortality. Both vaginal progesterone and cerclage individually have level 1 evidence supporting benefit in the prevention of preterm birth in pregnancies complicated by short cervical length. However, there is a paucity of level 1 evidence regarding the potential benefit of cerclage with progesterone relative to progesterone alone for short cervical length ≤25 mm in patients with singleton pregnancies without a history of spontaneous preterm birth.

OBJECTIVE

This study aimed to conduct a pragmatic randomized controlled trial to evaluate the additional benefit of cerclage with vaginal progesterone relative to vaginal progesterone alone in patients with singleton pregnancies without prior spontaneous preterm birth and with a current midtrimester transvaginal ultrasound cervical length ≤25 mm.

STUDY DESIGN

This was a multicenter international randomized controlled trial conducted from September 2017 to September 2023, involving 4 sites in the United States and Italy. Patients with singleton pregnancies without prior spontaneous preterm birth received transvaginal ultrasound cervical length (universal) screening during the midtrimester anatomy ultrasound examination as part of routine care. Inclusion criteria included transvaginal ultrasound cervical length ≤25 mm at 18 0/7 to 23 6/7 weeks. Exclusion criteria included current or planned cerclage, cervical dilation, symptoms of labor, infection, bleeding, and rupture of membranes at screening. Participants were randomized in a 1:1 ratio to cerclage with vaginal progesterone (200-mg vaginal progesterone daily) or vaginal progesterone alone. Randomization was stratified by study site and transvaginal ultrasound cervical length ≤15 mm. The primary outcome was preterm birth <35 weeks, assessed using intention-to-treat analysis. Secondary outcomes included preterm birth <37, 32, 28, and 24 weeks, gestational age at delivery, latency to delivery, and neonatal outcomes. Categorical variables were compared using the Pearson chi-square test and relative risk estimates with 95% confidence intervals. Continuous variables were compared using the Mann-Whitney U test. Latency to delivery and gestational age at delivery were also compared using Kaplan-Meier survival curves. Planned enrollment was set at N=206 on the basis of an estimated 0.54 relative risk with cerclage and a 34% incidence of preterm birth with standard care. The trial was registered on ClinicalTrials.gov (NCT03251729) on June 22, 2017.

RESULTS

Enrollment ran from September 22, 2017 to October 31, 2023, and was halted early because of lagging enrollment. A total of 93 participants were randomized; 3 were excluded because of withdrawal (n=1) and loss to follow-up (n=2). Of the 90 participants included in the intention-to-treat analysis, 43 were assigned to cerclage and progesterone and 47 to progesterone alone. Overall, 40 participants (40.4%) had a transvaginal ultrasound cervical length ≤15 mm. There was no significant difference in the primary outcome of preterm birth <35 weeks between those randomized to cerclage with progesterone vs progesterone alone (16.3% vs 23.4%; relative risk, 0.70 [0.30-1.63]). Those randomized to cerclage with progesterone had significantly increased latency from randomization to delivery (median difference, 13 [5-20] days; P=.01) and a significantly later gestational age at delivery (median difference, 1.0 [0.2-1.7] weeks; P=.035). A Kaplan-Meier survival curve also demonstrated increased latency to delivery and gestational age at delivery for cerclage with progesterone compared with progesterone alone (Mantel-Cox log-rank P<.001 and P=.003, respectively). These findings persisted within both subgroups of cervical length ≤15 mm and 16 to 25 mm.

CONCLUSION

In singleton gestations without a prior spontaneous preterm birth and a transvaginal ultrasound cervical length ≤25 mm before 24 weeks, cerclage with progesterone was not found to significantly reduce the preterm birth rate compared with progesterone alone. However, cerclage and progesterone did result in a significantly longer latency from randomization to delivery and a significantly later gestational age at delivery, compared to progesterone alone. These results suggest the potential benefit of cerclage and progesterone relative to progesterone alone in patients with singleton pregnancies without a prior spontaneous preterm birth and a short cervical length ≤25 mm before 24 weeks. This trial was halted early, and these findings should be confirmed in a larger trial or meta-analysis. El resumen está disponible en Español al final del artículo.

Targeting FKBP51 prevents stress-induced preterm birth

Preterm birth (PTB) is a leading cause of perinatal morbidity and mortality, with maternal stress-related disorders, such as depression and anxiety, linked to idiopathic PTB (iPTB). At the maternal-fetal interface, decidualized stromal cells (DSCs) exclusively express the progesterone receptor (PR) and play pivotal roles in maintaining pregnancy and initiating labor. DSCs also express FKBP51, a protein that binds to and inhibits transcriptional activity of glucocorticoid and PR receptors and is associated with stress-related diseases. We previously found that iPTB specimens exhibit increased FKBP51 levels and enhanced FKBP51-PR interactions in DSC nuclei. Additionally, we demonstrated that Fkbp5-deficient mice have prolonged gestation and are resistant to stress-induced PTB, suggesting that FKBP51 contributes to iPTB pathogenesis. Since no FDA-approved therapy exists for PTB, we hypothesized that inhibiting FKBP51 could prevent iPTB. Our current results show that the endogenous prostaglandin D2 derivative 15dPGJ2 reduces FKBP51 levels and FKBP51-PR interactions in cultured cells. Maternal stress increases uterine expression of Fkbp5, Oxtr, and Akr1c18, leading to shortened gestation. However, treatment with 15dPGJ2 lowers uterine Fkbp51, Oxtr, and Ptgs2 levels and prevents stress-induced PTB. Notably, co-treatment with 15dPGJ2 and either P4 or R5020 produced the most significant effects, highlighting the potential of 15dPGJ2 alone or in combination with progestins as a promising therapeutic strategy to prevent PTB.

Dynamic change of estrogen and progesterone metabolites in human urine during pregnancy

Endogenous estrogen and progesterone and their metabolites play a key role in regulating and maintaining the normal pregnancy process. However, the dynamic change of these estrogen and progesterone metabolites' level across the entire gestational period is not fully revealed. This study systematically measures the temporal changes of estrogen, progesterone, and their metabolites in human urine during normal pregnancy using ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). We find that the levels of estrone, estradiol, estriol, 16-epiestriol, 17-epiestriol, 2-methoxyestradiol, and 4-hydroxyestrone gradually increase during pregnancy. The levels of 2-hydroxyestrone, 2-hydroxyestradiol, and 4-hydroxyestradiol rapidly decrease in the early pregnancy and then maintain at lower levels. The levels of 4-methoxyestradiol, 4-methoxyestrone and 2-methoxyestrone peak in the mid-pregnancy and then gradually decrease. The levels of pregnenolone, 17α-hydroxy pregnenolone, 17α-hydroxy progesterone, pregnanolone, epipregnanolone gradually increase during pregnancy. The levels of progesterone, 20α-hydroxy progesterone, 5α-dihydroprogesterone and 5β-dihydroprogesterone first increase in the mid pregnancy and then decrease in the late pregnancy. In sum, this study comprehensively depicts the dynamic change of estrogen, progesterone, and their metabolites in human urine during pregnancy, which lays the foundation for hormone monitoring and early diagnosis of pregnancy complications, and further mechanistic study of the roles of these metabolites in pregnancy.

Management of cervical cerclage after preterm premature rupture of membranes: an argument for removal

Cervical cerclage is a widely used intervention to prevent preterm birth in high-risk pregnancies. However, cerclage is associate with risks, including preterm premature rupture of membranes and subsequent complications, such as chorioamnionitis. Our review evaluates the evidence for immediate removal (ie, removal at the time of diagnosis) vs retention of cervical cerclage (ie, removal when clinically indicated) after preterm premature rupture of membranes, focusing on optimizing neonatal outcomes and minimizing maternal and fetal complications. A meta-analysis on the topic that included 169 patients in the "removal" group and 208 in the "retention" group showed that the rates of pregnancy prolongation >48 hours and >7 days were significantly lower in the group who underwent immediate removal of cerclage than in the group who had delayed removal of cerclage (pregnancy prolongation >48 hours: 47% vs 85%, respectively; odds ratio, 0.15; pregnancy prolongation >7 days: 33% vs 57%, respectively; odds ratio, 0.30). In addition, pregnancy latency was significantly lower, despite the absolute mean difference being only 2.84 days. However, the rates of chorioamnionitis and Apgar score <7 at 5 minutes were significantly lower in the immediate removal group than in the retention group (chorioamnionitis: 29% vs 41%, respectively; odds ratio, 0.57; Apgar score <7 at 5 minutes: 16% vs 43%, respectively; odds ratio, 0.22). A proposed balanced approach involves retaining the cerclage for approximately 24 hours after premature rupture of membranes (PROM) to permit steroid administration (initial dose followed by a second dose after 24 hours) before removal. This strategy aims to maximize steroid benefits while minimizing the risks of prolonged cerclage retention, potentially achieving a correct timing that optimizes neonatal outcomes without significantly increasing complications This management approach could be beneficial in situations where immediate removal may preclude full steroid benefits. Our recommendations support a protocol balancing appropriate timing for steroid administration with the risks of extended cerclage retention, namely, chorioamnionitis, unless further randomized controlled trials will show the proper evidence-based management in this clinical scenario.

Vaginal progesterone for prevention of preterm birth in women with a history of preterm birth regardless of cervical length: an argument for use

It is well understood that preterm birth accounts for a substantial amount of poor neonatal outcomes. In 2022, preterm birth affected about 1 of every 10 infants born in the United States with complications ranging from mild respiratory distress syndrome to neonatal death. The complexity of the treatment is secondary to the fact that preterm birth is a multifactorial syndrome with intricate sociocultural factors that influence our racially disproportionate poor outcomes. One of the key risk factors for preterm birth is a history of spontaneous preterm birth. Currently, there are conflicting recommendations regarding the use of vaginal progesterone prophylactically for the prevention of recurrent preterm birth. As described in Practice Bulletin number 234 of the American College of Obstetricians and Gynecologists, the current recommendation is that patients with a singleton pregnancy and previous spontaneous preterm birth should be assessed with serial endovaginal ultrasound cervical length measurements to determine eligibility for vaginal progesterone. In contrast, the Society for Maternal-Fetal Medicine suggests the use of prophylactic vaginal progesterone with patient-centered counseling and shared decision-making. We aimed to present the rationale for the use of prophylactic vaginal progesterone in patients with singleton gestations and a history of spontaneous preterm birth.

Cervical assessment

Transvaginal scan (TVS) of cervical length (CxL) at mid-trimester anomaly scan in asymptomatic pregnancy is useful for predicting the risk of preterm birth. In symptomatic women, measurement of CxL at presentation can help to distinguish between true and false preterm labor (PTL), and who might not deliver within 48 h and seven days. In both groups, the individualization of risk would lead to improvement of antenatal care, including frequency of visits, patient education to identify earlier symptoms, avoid excessive hospitalization, and unnecessary steroids. It is also possible that vaginal progesterone and/or cerclage reduce the PTB risk on those asymptomatic women with short cervix. The aim is to review the evidence that supports the use of TVS of CxL in both asymptomatic and symptomatic pregnant women for the prediction and management of PTL.

Acute Placental Inflammation Is Associated with Reduced Progesterone Receptor Density in the Basal Decidua in Spontaneous Preterm Birth

OBJECTIVE

 A functional progesterone withdrawal has been thought to contribute to the pathophysiology of spontaneous preterm birth (PTB). The density of the progesterone receptor (PR) in gestational tissues could play a role in functional progesterone withdrawal. We sought to understand the relationship between placental pathology and the density of PR in the basal decidua in the setting of spontaneous preterm delivery.

STUDY DESIGN

 This is a secondary analysis of a retrospective cohort study of 40 patients with spontaneous PTB < 37 weeks from a prior study at NorthShore University HealthSystem previously described. Placental pathology was categorized according to the Amsterdam criteria into acute inflammation (AI), chronic inflammation (CI), maternal vascular malperfusion (MVM), and fetal vascular malperfusion (FVM). Slides containing basal decidua were stained for PR. Ten distinct images were obtained from the basal plate of each placenta. The positive cell detection program in QuPath image analysis software was used to estimate the percentage of cells positive for PR (%PR + ). The mean %PR+ cells were calculated from the ten representative images and were correlated with patterns of placental injury using t-tests. Models were adjusted for gestational age at delivery.

RESULTS

 The median gestational age at delivery was 32.5 weeks (interquartile range: 30.5, 34.1). There was a lower density of %PR+ cells among those with AI (12.9%PR+ without AI vs. 9.1%PR +  with AI, p = 0.03). There were no differences in the percent of %PR+ cells based on CI, MVM, or FVM. Models adjusted for gestational at delivery demonstrated persistent association with PR density and AI and no difference in the other pathologies.

CONCLUSION

 The presence of AI is associated with the lower density of PR expression in the basal decidua by quantitative immunohistochemical analysis. Further research is needed to investigate these findings in the context of spontaneous PTL and the prevention of PTB.

KEY POINTS

· AI is associated with a lower density of PR expression.. · PR is expressed in the basal decidua in the placenta.. · Further research is needed to investigate findings in the context of PTB..

Cervical elastography at 18 to 23 weeks to predict spontaneous preterm birth in individuals with a history of preterm birth

BACKGROUND

Individuals with a history of spontaneous preterm birth are at increased risk for recurrence in a subsequent pregnancy. Current methods used to predict those at highest risk are not precise. Cervical elastography is an investigational ultrasonographic technique that measures cervical tissue stiffness and may aid in identifying individuals at highest risk.

OBJECTIVE

This study aimed to assess the association between previously described cervical elastography measures-obtained using a semiautomatic application (E-cervix)-and preterm birth <37 weeks' gestation in a high-risk cohort with a history of spontaneous preterm birth.

STUDY DESIGN

Individuals with a singleton pregnancy between 18+0 and 23+6 weeks of gestation with a history of spontaneous preterm birth <37 weeks were prospectively enrolled. Exclusion criteria included the presence of a current cerclage or any uterine anomaly. The primary exposures were the E-cervix quantitative parameters (internal os stiffness, external os stiffness, internal-to-external os stiffness ratio, hardness ratio, and elasticity contrast index), which were measured at the time of enrollment. Transvaginal cervical length was also measured as an exposure to compare the current standard of care and accepted cutpoint of 25 mm alongside the E-cervix parameters. The primary outcome was preterm birth <37 weeks. The intra- and interrater reliability intraclass correlation coefficient for each parameter was calculated using a mixed-effects model. The area under the curve was derived from receiver operating characteristic curves to evaluate the association of each parameter with the primary outcome, and the optimal cutpoints for each continuous parameter were identified. Multivariable logistic regression was performed for the parameters that were either significant on univariate analysis or had an area under the curve of ≥0.6, using the calculated cutpoint to create a binary exposure and adjusting for gestational age at the earliest prior preterm birth, number of prior preterm births, and progesterone use. A sensitivity analysis was performed excluding medically indicated preterm birth.

RESULTS

Of the enrolled 245 individuals with a history of spontaneous preterm birth, 69 (28%) had preterm birth <37 weeks. Intrarater and interrater reliability were good for all parameters (intrarater: 0.60-0.74; interrater: 0.62-0.71). In univariate analysis, only the internal-to-external os stiffness ratio was significantly associated with increased risk of preterm birth compared with no preterm birth (0.97±0.23 vs 0.90±0.20; P=.01). Cervical length, internal os stiffness, external os stiffness, hardness ratio, and elasticity contrast index did not show significant associations. The area under the curve for external os stiffness was 0.6, indicating a good association, whereas the values for the remaining parameters were satisfactory (0.51-0.59). In multivariable logistic regression analysis, an internal-to-external os stiffness ratio ≥1.0 was associated with 2-fold higher odds of preterm birth <37 weeks (adjusted odds ratio, 2.48; confidence interval, 1.34-4.58), and an external os stiffness ≥30 (indicating lower tissue stiffness) was associated with 46% reduced odds of preterm birth <37 weeks (adjusted odds ratio, 0.54; confidence interval, 0.30-0.97). Cervical length <25 mm was not associated with preterm birth.

CONCLUSION

Elastography with E-cervix technology can be reliably assessed in a cohort of women with prior preterm birth. The parameter most useful for predicting preterm birth was an internal-to-external os stiffness ratio ≥1.0, whereas cervical length <25 mm was not predictive in our cohort.

Assessing the applicability of obstetrical randomized controlled trials in real-world practices

This article examines the applicability of obstetrical randomized controlled trials (RCTs) in the real-world and proposes a classification of the value of these trials based on their potential for achieving sustainable practices. In the context of this discussion, real-world results pertain to the potential impact of the RCT on sustainable interventions and practices, and its implications for healthcare practice or policy, in the country (or countries) that was conducted. While RCTs are generally regarded as the gold standard of medical evidence, their effectiveness in producing meaningful real-world results depends, among various other factors, on the clarity and specificity of the trial definitions used for diagnosis (characteristics of the study group or enrollment criteria) and treatment (intervention). The definitions used for diagnosis and treatment, especially in pragmatic trials, can influence the likelihood for real-world implementation. By analyzing notable obstetrical RCTs, the authors find that trials with well-defined diagnoses and treatments that can be implemented without specialized expertise are more likely to generate results that are relevant to general practice, indicating higher value. In contrast, RCTs with ambiguous or undefined diagnoses and treatments often lead to variations in practice and produce unreliable real-world outcomes and practices suggesting lower value. Recognizing this variability can offer valuable guidance for the design and evaluation of RCTs in obstetrics.

Comparing transabdominal and transvaginal cervical length measurements at mid-trimester fetal anomaly scan: The impact of bladder fullness and lower uterine contractions

Purpose

To assess the effects of bladder fullness and lower uterine contractions ultrasound on transabdominal and transvaginal cervical length measurements at the mid-trimester fetal anomaly scan (FAS).

Methods

Transabdominal and transvaginal cervical length measurements from 925 mid-trimester FAS examinations were retrospectively analysed. Images were assessed for lower uterine contraction and bladder fullness using a novel qualitative assessment. Bland-Altman plots and single-score interclass correlation (ICC) were used to determine correlation between transabdominal and transvaginal measurements. Sensitivity and specificity of transabdominal cut-offs were calculated.

Results

Transabdominal and transvaginal measurements of the cervix correlated poorly (ICC 0.306). An overfilled bladder and lower uterine contractions on average increased the length of transabdominal cervical length measurements. Removing these variables did not significantly improve correlation between transabdominal and transvaginal measurements of the cervix but resulted in an improved sensitivity of transabdominal assessment to detect a clinically relevant short cervix.

Discussion

Resolving the confounding factors of an overfilled bladder and lower uterine contractions can help improve the our ability to detect a short cervix on transabdominal ultrasound. Our data set supported a two-stage approach to cervical length screening which would allow 100% sensitivity when a cut-off of ≤35 mm is used on transabdominal ultrasound and would limit the need for transvaginal scanning to approximately 39% of patients. This cut-off is in line with the findings of other studies. The low prevalence of short cervix in our study did however make it difficult to extrapolate reliable calculations.

Conclusion

Although transabdominal measurements correlate poorly with transvaginal measurements of the cervix, we demonstrated an improved sensitivity for detecting a short cervix using a transabdominal approach when no contractions or overfilled bladder is present. This potential could be explored in a future study with a larger sample size.

Rate of preterm delivery and latency period in asymptomatic patients undergoing cerclage for very short cervix ≤10.0 mm

BACKGROUND

In asymptomatic women with cervical length ≤10 mm, vaginal progesterone has a limited effect in reducing the rate of preterm delivery.

OBJECTIVE

This study aimed to estimate the rate of preterm delivery and mean latency period to delivery in asymptomatic women with no history of preterm delivery and a cervical length of ≤10.0 mm undergoing or not undergoing cerclage and who were not treated with vaginal progesterone.

STUDY DESIGN

This was a retrospective analysis of asymptomatic patients with singleton pregnancies and no history of preterm delivery with an incidental finding of a cervical length of ≤10.0 mm measured by transvaginal ultrasound during midtrimester scan. Of note, 56 patients (63.6%) underwent cerclage placement and 32 patients (36.4%) did not, none of them received vaginal progesterone. Patients with evidence of advanced dilation, prolapsing membranes, ruptured membranes, or positive signs of infection were not candidates for cerclage placement and were excluded from the analysis. Differences in the prevalence of preterm delivery, mean gestational age at delivery, and mean latency from very short cervix identification to delivery between the 2 groups were calculated. Associations between cerclage and preterm delivery adjusted for maternal characteristics and fetal weight were estimated.

RESULTS

The median gestational ages at the time of cervical length measurement were 20 6/7 weeks (interquartile range, 17 5/7 to 23 3/7) in the cerclage group and 21 5/7 weeks (interquartile range, 17 6/7 to 23 6/7) in the no-cerclage group (P=.02). No difference in cervical length was observed between patients who had a cerclage (5.9±3.1 mm) and those who did not have a cerclage (6.5±3.2 mm) (P=.4). The prevalence of preterm delivery in women with cerclage vs women without cerclage was as follows: PTD at <37 weeks of gestation (31/56 [55.3%] in the cerclage group vs 28/32 [87.5%] in the no-cerclage group; adjusted odds ratio, 0.17; 95% confidence interval, 0.05-0.62; P=.008), PTD at ≤34 weeks of gestation (27/56 [48.2%] in the cerclage group vs 24/32 [75.0%] in the no-cerclage group; adjusted odds ratio, 0.16; 95% confidence interval, 0.05-0.55; P=.02), and PTD at ≤28 weeks of gestation (19/56 [33.9%] in the cerclage group vs 22/32 [68.7%] in the no-cerclage group; adjusted odds ratio, 0.15; 95% confidence interval, 0.05-0.51; P=.002). The median gestational ages at delivery were 32 6/7 weeks (interquartile range, 19 1/7 to 40 1/7) in the cerclage group and 28 1/7 weeks (interquartile range, 20 1/7 to 40 2/7) in the no-cerclage group (P=.001). The median latencies from the time of cervical length measurement to delivery were 84 days (interquartile range, 8-144) in the cerclage group and 43 days (interquartile range, 1-146) in the no-cerclage group (P=.003).

CONCLUSION

Among low-risk asymptomatic women with a very short cervix (≤10.0 mm) in the midtrimester of pregnancy, women treated with cerclage have an increased latency to delivery and a lower prevalence of preterm delivery than those treated with expectant management.

Possible Efficacy of Vaginal Progesterone on Asymptomatic Women with a Short Cervix after 24 Weeks of Gestation: A Historical Cohort Study in Japan

Introduction

Few studies have explored the preventive efficacy of vaginal progesterone (VD) treatment for preterm delivery (PTD) in Japanese clinical practice. In this study, the efficacy of the VD treatment in pregnant women with a short cervix (sCX) diagnosed after 24 weeks is evaluated, focusing on perinatal outcomes.

Methods

A retrospective historical cohort study. Clinical data of 273 singleton women hospitalized for preventing PTD were extracted. Inclusion criteria are diagnosed sCX at 24-33 weeks. We excluded women with factors including treatment start before 24 weeks, medically induced PTD, PTD on admission day, and fetal demise. Consequently, logistic regression analyses were conducted on data from 79 women during Period 1 (November 2015 to March 2018, using prolonged intravenous ritodrine hydrochloride) and 82 women during Period 2 (August 2018 to August 2022, implementing VD treatment), adjusting maternal age, parity, body mass index, gestational age, cervical length, and histological chorioamnionitis. The primary outcomes involved PTD <37 and <34 weeks and neonatal intensive care unit admission. Secondary outcomes included the interval from the diagnosis of sCX to delivery <14 and <28 days, infant intubation, and surfactant administration. Since VD use is off-label in Japan, we obtained written informed consent prior to treatment.

Results

VD treatment (Period 2) significantly decreased the incidence of PTD (birth < 37 weeks) (adjusted odds ratios [ORs] 0.43, 95% confidence intervals [CIs] 0.19-0.96), impending delivery within 14 and 28 days after confirming sCX (adjusted OR 0.12, 95% CI 0.06-0.72; adjusted OR 0.25, 95% CI 0.09-0.74, respectively), and neonatal intubation rate (adjusted OR 0.17, 95% CI 0.04-0.75).

Conclusions

The VD treatment can prevent PTD in asymptomatic women with sCX diagnosed after 24 weeks of gestation. Although further validation is warranted, these findings may contribute to expanding the use of VD treatment in Japanese clinical practice.

Nanomedicine for Maternal and Fetal Health

Conception, pregnancy, and childbirth are complex processes that affect both mother and fetus. Thus, it is perhaps not surprising that in the United States alone, roughly 11% of women struggle with infertility and 16% of pregnancies involve some sort of complication. This presents a clear need to develop safe and effective treatment options, though the development of therapeutics for use in women's health and particularly in pregnancy is relatively limited. Physiological and biological changes during the menstrual cycle and pregnancy impact biodistribution, pharmacokinetics, and efficacy, further complicating the process of administration and delivery of therapeutics. In addition to the complex pharmacodynamics, there is also the challenge of overcoming physiological barriers that impact various routes of local and systemic administration, including the blood-follicle barrier and the placenta. Nanomedicine presents a unique opportunity to target and sustain drug delivery to the reproductive tract and other relevant organs in the mother and fetus, as well as improve the safety profile and minimize side effects. Nanomedicine-based approaches have the potential to improve the management and treatment of infertility, obstetric complications, and fetal conditions.

Cervical length measurement between 11 and 13 + 6 weeks of pregnancy: Comparison of maternal and ultrasonographic characteristics between term and preterm deliveries

OBJECTIVE

The aim of this study was to evaluate the maternal and ultrasonographic characteristics of pregnant women who underwent cervical length (CL) measurement by transvaginal ultrasound between 11 and 13 + 6 weeks of gestation and who delivered at term or preterm.

METHODS

A retrospective cohort study was carried out between March 2013 and December 2018 by analyzing ultrasound data of singleton pregnant women who underwent CL measurement by transvaginal ultrasound during the first trimester scan. CL was compared between the two groups (full-term and preterm birth [PB]) using Student's t-test.

RESULTS

A total of 5097 pregnant women were enrolled, of whom 5061 (99.3%) had term and 36 (0.7%) had PB < 34 weeks. CL measurements did not differ between the term and preterm groups (36.62 vs. 37.83 mm, p = 0.08). Maternal age showed a significant and linear association with CL (r = 0.034, p = 0.012) and CRL (r = 0.086, p < 0.001). Smoking status was associated with shorter CL (36.64 vs. 35.09 mm, p = 0.003). When we analyzed the CL of the pregnant women in the term and preterm groups, according to the gestational age cut-offs for prematurity (28, 30, 32, and 34 weeks), we found that there was no significant difference between the measurements in all groups (p > 0.05).

CONCLUSION

We observed no significant differences between CL measurements between 11 and 13 + 6 weeks in pregnant women who had preterm and term deliveries. Gestational age and CRL showed a significant and linear association with CL measurement.

Low Levels of Complement Factor H in the First Trimester of Pregnancy Are Associated with Spontaneous Preterm Birth

Preterm birth (PTB) remains a significant public health concern, and prediction is an important objective, particularly in the early stages of pregnancy. Many studies have relied on cervical characteristics in the mid-trimester, with limited results. It is therefore crucial to identify novel biomarkers to enhance the ability to identify women at risk. The complement pathway is implicated in the process of placentation, and recent proteomics studies have highlighted the potential roles of some complement proteins in the pathophysiology of PTB. To determine the association between the occurrence of spontaneous preterm birth (sPTB) and the concentration of complement C3, factor B, and factor H in the blood of pregnant women during the first trimester. This prospective cohort study included women with singleton pregnancies, both with and without a history of sPTB, from two health institutions in Bucaramanga, Colombia. The outcome was sPTB before 37 weeks. A blood sample was obtained between 11 + 0 to 13 + 6 weeks. ELISA immunoassay was performed to quantify the levels of C3, factor B, and factor H. A total of 355 patients were analyzed, with a rate of sPTB of 7.6% (27/355). The median plasma concentration for C3, factor B, and factor H were 488.3 μg/mL, 352.6 μg/mL, and 413.2 μg/mL, respectively. The median concentration of factor H was found to be significantly lower in patients who delivered preterm compared to patients who delivered at term (382 μg/mL vs. 415 μg/mL; p = 0.034). This study identified a significant association between low first-trimester levels of factor H and sPTB before 37 weeks. These results provide relevant information about a new possible early biomarker for sPTB. However, the results must be confirmed in different settings, and the predictive value must be examined.

Cerclage Plus Adjuvant Vaginal Progesterone for Preterm Birth Prevention in Patients with a Short or Dilated Cervix without Prior Preterm Birth

OBJECTIVE

 The primary objective was to determine if vaginal progesterone following cerclage for cervical length <10 mm or cervical dilation in patients without a history of spontaneous preterm birth (sPTB) decreased the risk of preterm birth at <34 weeks' gestation compared with cerclage alone. Secondary objectives were to determine if vaginal progesterone following cerclage (1) decreased the risk of preterm birth at <24, <28, and <37 weeks' gestation and (2) increased the latency period from cerclage placement to delivery compared with treatment with cerclage alone.

STUDY DESIGN

 Multicenter retrospective cohort study from 2015 to 2020 of singleton pregnancies, without prior sPTB, who had cerclage placement <24 weeks' gestation for cervical length <10 mm or cervical dilation. Exposure defined as cerclage plus vaginal progesterone postoperatively (dual therapy) and unexposed as cerclage alone (monotherapy), based on surgeon preference.

RESULTS

 We included 122 patients, 78 (64%) treated with dual therapy and 44 (36%) treated with monotherapy. In the crude analysis, dual therapy was associated with a lower risk of delivery at <28 weeks' gestation (13%) compared with monotherapy (34%; crude risk ratio: 0.38 [95% confidence interval (CI): 0.19-0.75]). When adjusted for preoperative vaginal progesterone, results were attenuated (adjusted risk ratio: 0.45 [95% CI: 0.20-1.01]). In both the crude and adjusted analyses, the risk of sPTB was not statistically different at <24, <34 or <37 weeks' gestation. Dual therapy was associated with a greater pregnancy latency from cerclage to delivery (16.3 vs. 14.4 weeks; p = 0.04), and greater gestational age at delivery (37.3 vs. 35.8 weeks' gestation; p = 0.02) compared with monotherapy.

CONCLUSION

 While not statistically significant, the risk of sPTB was lower at all gestational ages studied in patients treated with dual therapy compared with monotherapy. Dual therapy was associated with longer pregnancy latency and greater gestational age at delivery compared with monotherapy.

KEY POINTS

· Dual therapy did not decrease preterm birth risk compared with monotherapy.. · Dual therapy prolonged pregnancy compared with monotherapy.. · Dual therapy can be considered but further studies are needed..

The Effect of Maternal Parity on Preterm Birth Risk in Women with Short Mid-Trimester Cervical Length: A Retrospective Cohort Study

Objectives: To evaluate the effect of maternal parity on the association between mid-trimester cervical length and preterm birth to elucidate the potential intricacies of this relationship. Methods: A retrospective cohort study using Electronic Medical Records (EMR) data. The study population included pregnant women with a singleton fetus and a short mid-trimester cervical length, recorded in the EMR system at a large health maintenance organization. Women were categorized by parity in the current pregnancy, and a statistical analysis was conducted to examine the relationship between parity and premature delivery. Results: Data were collected from 1144 records of cervical length measurements of 738 pregnancies obtained from the HMO database. The study population consisted of 259 nulliparous women (35.1%), 451 multiparous women (61.1%), and 28 grand multiparous women (3.8%). The results from the multivariate analysis of the primary outcome showed that nulliparity was significantly associated with an increased risk of premature delivery, with a risk of 1.557 for nulliparous women compared to parous women. Conclusions: In this study, a statistically significant association was found between nulliparity and preterm birth among women with a short mid-trimester cervical length. Nulliparous women were found to have a higher risk of preterm birth in the current pregnancy compared to parous women. Further research is needed to understand the underlying mechanisms and to develop targeted interventions to reduce the risk of premature birth in this population. These findings highlight the need to consider nulliparity as a potential risk factor in the management of pregnancies with a shortened cervix.

SMFM Consult Series #70: Management of short cervix in individuals without a history of spontaneous preterm birth

Most deliveries before 34 weeks of gestation occur in individuals with no previous history of preterm birth. Midtrimester cervical length assessment using transvaginal ultrasound is one of the best clinical predictors of spontaneous preterm birth. This Consult provides guidance for the diagnosis and management of a short cervix in an individual without a history of preterm birth. The following are Society for Maternal-Fetal Medicine recommendations: (1) we recommend that all cervical length measurements used to guide therapeutic recommendations be performed using a transvaginal approach and in accordance with standardized procedures as described by organizations such as the Perinatal Quality Foundation or the Fetal Medicine Foundation (GRADE 1C); (2) we recommend using a midtrimester cervical length of ≤25 mm to diagnose a short cervix in individuals with a singleton gestation and no previous history of spontaneous preterm birth (GRADE 1C); (3) we recommend that asymptomatic individuals with a singleton gestation and a transvaginal cervical length of ≤20 mm diagnosed before 24 weeks of gestation be prescribed vaginal progesterone to reduce the risk of preterm birth (GRADE 1A); (4) we recommend that treatment with vaginal progesterone be considered at a cervical length of 21 to 25 mm based on shared decision-making (GRADE 1B); (5) we recommend that 17-alpha hydroxyprogesterone caproate, including compounded formulations, not be prescribed for the treatment of a short cervix (GRADE 1B); (6) in individuals without a history of preterm birth who have a sonographic short cervix (10-25 mm), we recommend against cerclage placement in the absence of cervical dilation (GRADE 1B); (7) we recommend that cervical pessary not be placed for the prevention of preterm birth in individuals with a singleton gestation and a short cervix (GRADE 1B); and (8) we recommend against routine use of progesterone, pessary, or cerclage for the treatment of cervical shortening in twin gestations outside the context of a clinical trial (GRADE 1B).

Neonatal Outcomes after Maternal Biomarker-Guided Preterm Birth Intervention: The AVERT PRETERM Trial

The AVERT PRETERM trial (NCT03151330) evaluated whether screening clinically low-risk pregnancies with a validated maternal blood biomarker test for spontaneous preterm birth (sPTB) risk, followed by preventive treatments for those screening positive, would improve neonatal outcomes compared to a clinically low-risk historical population that had received the usual care. Prospective arm participants with singleton non-anomalous pregnancies and no PTB history were tested for sPTB risk at 191/7-206/7 weeks' gestation and followed up with after neonatal discharge. Screen-positive individuals (≥16% sPTB risk) were offered vaginal progesterone (200 mg) and aspirin (81 mg) daily, with twice-weekly nurse phone calls. Co-primary outcomes were neonatal morbidity and mortality, measured using a validated composite index (NMI), and neonatal hospital length of stay (NNLOS). Endpoints were assessed using survival analysis and logistic regression in a modified intent-to-treat population comprising screen-negative individuals and screen-positive individuals accepting treatment. Of 1460 eligible participants, 34.7% screened positive; of these, 56.4% accepted interventions and 43.6% declined. Compared to historical controls, prospective arm neonates comprising mothers accepting treatment had lower NMI scores (odds ratio 0.81, 95% CI, 0.67-0.98, p = 0.03) and an 18% reduction in severe morbidity. NNLOS was shorter (hazard ratio 0.73, 95% CI, 0.58-0.92, p = 0.01), with a 21% mean stay decrease among neonates having the longest stays. Sensitivity analyses in the entire intent-to-treat population supported these findings. These results suggest that biomarker sPTB risk stratification and preventive interventions can ameliorate PTB complications in singleton, often nulliparous, pregnancies historically deemed low risk.

Assessing the multifaceted cervix: examining cervical gland area at cervical length screening to predict spontaneous preterm birth

BACKGROUND

Biologically active cervical glands provide a mucous barrier while influencing the composition and biomechanical strength of the cervical extracellular matrix. Cervical remodeling during ripening may be reflected as loss of the sonographic cervical gland area. As sonographic cervical length remains suboptimal for universal screening, adjunctive evaluation of other facets of the mid-trimester cervix may impart additional screening benefit.

OBJECTIVE

To sonographically assess the cervical gland area at universal cervical length screening for preterm birth.

STUDY DESIGN

We performed a retrospective cohort study of singletons with transvaginal cervical length screening universally performed during anatomic survey between 18 0/7 and 23 6/7 weeks and subsequent live delivery at a single institution in 2018. Uterine anomalies, cerclage, suboptimal imaging, or medically indicated preterm birth were excluded. Ultrasound images were assessed for cervical length and cervical gland area (with quantitative measurements when present). The primary outcome was spontaneous preterm birth <37 weeks. Absent and present gland groups were compared using χ2, Fisher's exact, T-test, and multivariate logistic regression (adjusting for parity and progesterone use, as well as the gestational age, cervical length, and gland absence at screening ultrasound). Gland measurements were evaluated using the Mann-Whitney-U Test and Spearman's correlation.

RESULTS

Among the cohort of 772 patients, absent and present CGA groups were overall similar. Patients were on average 33 years old, ∼20 weeks gestation at screening ultrasound, and overall, 2.5% had history of prior spontaneous preterm birth. The absent gland group was more likely to have been taking progesterone (17% vs 4%, P=.04). Overall rate of preterm birth was 2.6%. However, the 2.3% of patients with absent cervical gland area were significantly more likely to deliver <37 weeks (aOR 23.9, 95% CI 6.4-89, P<.001). Multivariate logistic regression demonstrated better performance of a cervical length screening model for preterm birth prediction with the addition of qualitative gland evaluation (P<.001). Qualitative gland assessment was reproducible (PABAK 0.89), but quantitative gland measurements did not correlate with preterm birth.

CONCLUSION

Qualitative gland absence at mid-gestation cervical length screening was associated with subsequent spontaneous preterm birth, whereas quantitative gland measurements were not. Multifaceted ultrasound screening may be needed to adequately evaluate the multiple biologic functions of the cervix.

The vaginal immunoproteome for the prediction of spontaneous preterm birth: A retrospective longitudinal study

Background

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Most cases of preterm birth occur spontaneously and result from preterm labor with intact (spontaneous preterm labor [sPTL]) or ruptured (preterm prelabor rupture of membranes [PPROM]) membranes. The prediction of spontaneous preterm birth (sPTB) remains underpowered due to its syndromic nature and the dearth of independent analyses of the vaginal host immune response. Thus, we conducted the largest longitudinal investigation targeting vaginal immune mediators, referred to herein as the immunoproteome, in a population at high risk for sPTB.

Methods

Vaginal swabs were collected across gestation from pregnant women who ultimately underwent term birth, sPTL, or PPROM. Cytokines, chemokines, growth factors, and antimicrobial peptides in the samples were quantified via specific and sensitive immunoassays. Predictive models were constructed from immune mediator concentrations.

Results

Throughout uncomplicated gestation, the vaginal immunoproteome harbors a cytokine network with a homeostatic profile. Yet, the vaginal immunoproteome is skewed toward a pro-inflammatory state in pregnant women who ultimately experience sPTL and PPROM. Such an inflammatory profile includes increased monocyte chemoattractants, cytokines indicative of macrophage and T-cell activation, and reduced antimicrobial proteins/peptides. The vaginal immunoproteome has improved predictive value over maternal characteristics alone for identifying women at risk for early (<34 weeks) sPTB.

Conclusions

The vaginal immunoproteome undergoes homeostatic changes throughout gestation and deviations from this shift are associated with sPTB. Furthermore, the vaginal immunoproteome can be leveraged as a potential biomarker for early sPTB, a subset of sPTB associated with extremely adverse neonatal outcomes.

Funding

This research was conducted by the Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS) under contract HHSN275201300006C. ALT, KRT, and NGL were supported by the Wayne State University Perinatal Initiative in Maternal, Perinatal and Child Health.

Vaginal Progesterone to Prevent Spontaneous Preterm Birth in Women With a Sonographic Short Cervix: The Story of the PREGNANT Trial

The PREGNANT trial was a randomized, placebo-controlled, multicenter trial designed to determine the efficacy and safety of vaginal progesterone (VP) to reduce the risk of birth < 33 weeks and of neonatal complications in women with a sonographic short cervix (10 to 20 mm) in the mid-trimester (19 to 23 6/7 wk). Patients allocated to receive VP had a 45% lower rate of preterm birth (8.9% vs 16.1%; relative risk = 0.55; 95% CI: 0.33-0.92). Neonates born to mothers allocated to VP had a 60% reduction in the rate of respiratory distress syndrome. This article reviews the background, design, execution, interpretation, and impact of the PREGNANT Trial.

Universal cervical length screening and risk of spontaneous preterm birth: a systematic review and meta-analysis

OBJECTIVE

To evaluate the risk of spontaneous preterm birth with or without universal transvaginal ultrasound cervical length screening at the time of midtrimester scan.

DATA SOURCES

Medline, Embase, ClinicalTrials.gov, and Web of Science were systematically searched from the inception of the databases to November 12, 2023, using combinations of the relevant medical subject heading terms, key words, and word variants that were considered suitable for the topic.

STUDY ELIGIBILITY CRITERIA

Studies including individuals with singleton gestations at 16-25 weeks of gestation screened or not screened with universal transvaginal ultrasound cervical length screening were considered eligible. Primary outcome was spontaneous preterm birth <37 weeks; secondary outcomes were spontaneous preterm birth <34 and <32 weeks.

METHODS

Random effect head-to-head analyses were used to directly compare each outcome, expressing the results as summary odds ratio and relative 95% confidence interval. The quality of the included studies was independently assessed by 2 reviewers, using the Newcastle-Ottawa scale for cohort studies and the Cochrane risk-of-bias tool for randomized controlled studies. The study was registered on the prospective register of systematic reviews database (PROSPERO) (registration number: CRD42022385325).

RESULTS

Eight studies, including 447,864 pregnancies, were included in the meta-analysis (213,064 screened with transvaginal ultrasound cervical length and 234,800 unscreened). In the overall analysis, universal transvaginal ultrasound cervical length did not significantly decrease the spontaneous preterm birth rates <37 weeks (odds ratio, 0.92 [95% confidence interval, 0.84-1.01], P=.07) and <34 weeks (odds ratio, 0.87 [95% confidence interval, 0.73-1.04], P=.12), but was significantly associated with a lower risk of spontaneous preterm birth <32 weeks (odds ratio, 0.84 [95% confidence interval, 0.76-0.94], P=.002). Individuals without a prior spontaneous preterm birth had a significantly lower risk of spontaneous preterm birth <37 weeks (odds ratio, 0.88 [95% confidence interval, 0.79-0.97], P=.01) and a lower trend of spontaneous preterm birth <32 weeks (odds ratio, 0.82 [95% confidence interval, 0.66-1.01], P=.06) when screened with transvaginal ultrasound cervical length, compared with no screening.

CONCLUSION

Universal transvaginal ultrasound cervical length screening usually <24 weeks in singletons without a prior spontaneous preterm birth, is associated with a significant reduction in spontaneous preterm birth <37 weeks, compared with no screening.

Reduction in cervical length after vaginal progesterone in women with short cervix is significantly associated with preterm delivery at ≤ 34 weeks and < 37 weeks of gestation

OBJECTIVE

To evaluate the association between changes in cervical length (CL) after vaginal progesterone treatment and preterm delivery (PTD).

METHODS

This was a retrospective cohort study that included 197 singleton pregnancies without (n = 178) and with (n = 19) a history of PTD which were found to have a short cervix (≤ 25 mm) between 18 + 0 and 23 + 6 weeks' gestation with a follow-up transvaginal CL measurement taken at least 1 week after vaginal progesterone treatment started. Receiver-operating-characteristics (ROC)-curve analysis was performed and three CL shortening patterns were evaluated: (1) ≥ 10% reduction; (2) ≥ 20% reduction; and (3) ≥ 5 mm reduction relative to the first CL measurement. The predictive performance of each CL reduction cut-off and its association with PTD ≤ 34 weeks and PTD < 37 weeks were evaluated.

RESULTS

Overall, the rate of PTD ≤ 34 weeks was 16.8% (33/197) and that of PTD < 37 weeks was 36.5% (72/197). The area under the ROC curve of cervical shortening expressed in % for predicting PTD ≤ 34 weeks and PTD < 37 weeks was 0.703 and 0.608, respectively. Cervical shortening was observed in 60/197 (30.5%) patients, with 49/60 (81.7%) women showing ≥ 10% reduction, 32/60 (53.3%) ≥ 20% reduction and 27/60 (45.0%) ≥ 5 mm reduction in CL. Sensitivity and specificity for PTD ≤ 34 weeks were, respectively, 48.5% and 79.9% for ≥ 10% reduction; 36.4% and 87.8% for ≥ 20% reduction; and 27.3% and 89.0% for ≥ 5 mm reduction in CL. For PTD < 37 weeks, sensitivity and specificity were, respectively, 36.1% and 81.6% for ≥ 10% reduction; 27.8% and 90.4% for ≥ 20% reduction; and 20.8% and 90.4% for ≥ 5 mm reduction in CL. The highest positive likelihood ratios for PTD ≤ 34 and < 37 weeks were for ≥ 20% CL reduction (2.98 (95% CI, 1.62-5.49) and 2.89 (95% CI, 1.52-5.57), respectively). Despite significant differences in sensitivity among the different cut-offs for cervical shortening, favoring the ≥ 10% reduction cut-off, a reduction of ≥ 20% in CL showed the strongest association with PTD ≤ 34 weeks (odds ratio (OR), 4.11 (95% CI, 1.75-9.62)) and < 37 weeks (OR, 3.62 (95% CI, 1.65-7.96)), as compared with a less pronounced reduction in CL.

CONCLUSIONS

In women with a short cervix treated with vaginal progesterone, a reduction in CL on a subsequent ultrasound scan can predict PTD ≤ 34 and < 37 weeks. A ≥ 20% reduction in CL had the highest positive likelihood ratio and strongest association with PTD ≤ 34 and < 37 weeks compared with ≥ 10% or ≥ 5 mm reduction. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

First-trimester and early-second-trimester transvaginal cervical length before 16 weeks among women with preterm and term birth: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the differences in first-trimester and early-second-trimester transvaginal cervical length between patients with spontaneous preterm birth and those with term birth.

DATA SOURCES

PubMed, MEDLINE, Embase, and the Cochrane Library were systematically searched through August 2023.

STUDY ELIGIBILITY CRITERIA

Studies had to include (1) transvaginal cervical length measurement before 16+0 weeks of gestation and (2) transvaginal cervical length measurement in a population of patients who delivered preterm and at term. Abstracts, studies with duplicated data, and those with cervical length measured by transabdominal ultrasound scan were excluded.

METHODS

K.W.C. and J.L. searched for, screened, and reviewed the articles independently. The quality of the studies was assessed using the Newcastle-Ottawa scale. Mean differences were calculated using a random-effects model and pooled through a meta-analysis.

RESULTS

A total of 5727 published articles were identified. Only 10 studies (which analyzed 22,151 pregnancies) met the inclusion criteria. All studies excluded iatrogenic preterm birth. Transvaginal cervical length was significantly shorter in women with spontaneous preterm birth than in those who delivered at term (mean difference, -0.97; 95% confidence interval, -1.65 to -0.29; P=.005; I2=69%). When a linear technique was used to measure transvaginal cervical length, a significantly shorter transvaginal cervical length was associated with spontaneous preterm birth as opposed to term birth (mean difference, -1.09; 95% confidence interval, -1.96 to -0.21; P=.02; I2=77%). A shorter transvaginal cervical length measured by other techniques was also associated with spontaneous preterm birth before 34 to 35 weeks (mean difference, -1.87; 95% confidence interval, -3.04 to -0.70; P=.002; I2=0%). When studies where interventions were given for a "short" cervix or studies with a mean transvaginal cervical length ≥40 mm were excluded, a significantly shorter transvaginal cervical length was observed among those with spontaneous preterm birth (mean difference, -1.13; 95% confidence interval, -1.89 to -0.37; P=.004; mean difference, -0.86; 95% confidence interval, -1.67 to -0.04; P=.04; respectively). The optimal transvaginal cervical length cutoff was 38 to 39 mm, yielding pooled sensitivity of 0.80, specificity of 0.45, positive likelihood ratio of 1.16, negative likelihood ratio of 0.33, diagnostic odds ratio of 5.12, and an area under the curve of 0.75.

CONCLUSION

Women with spontaneous preterm birth had significantly shorter transvaginal cervical length before 16 weeks of gestation compared with those who delivered at term. The linear method and the 2-line method are acceptable techniques for measuring transvaginal cervical length.

Effects of vaginal progesterone and placebo on preterm birth and antenatal outcomes in women with singleton pregnancies and short cervix on ultrasound: a meta-analysis

Background

Vaginal progesterone in preterm birth and adverse outcomes caused by cervical insufficiency remains controversial. To address it, the effect of vaginal progesterone on preterm delivery and perinatal outcome of single pregnancy women with short cervix (less than 25 mm) was systematically evaluated by meta-analysis.

Methods

"Vaginal progesterone," "placebo," "ultrasound," "cervix," "singleton pregnancy," "preterm birth," and "antenatal outcomes" were entered to screen clinical studies PubMed, Embase, and the Chinese Biomedical Literature Database (CBM). The study population consisted of women with singleton pregnancies and a short cervix on ultrasound, and were assigned into the progesterone group (n = 1,368) and the placebo group (n = 1,373). Treatment began after the patient was diagnosed with short cervix until delivery. Neonatal survival rate, Neonatal Intensive Care Unit (NICU) admission rate, respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), neonatal mortality, and birth weight <1,500 g were analyzed.

Results

A total of 8 articles, totaling 2,741 study subjects, were enrolled. The progesterone group exhibited an obvious reduced rate of preterm birth at <34 weeks (OR = 0.67, 95% CI: 0.53∼0.84; Z = 3.53, P = 0.004), preterm birth at <32 weeks (OR = 0.46, 95% CI: 0.28∼0.77; Z = 2.99, P = 0.003), NICU admission rate (OR = 0.45, 95% CI: 0.30∼0.66; Z = 0.15, P < 0.0001), RDS rate (OR = 0.42, 95% CI: 0.28∼0.63; Z = 4.25, P < 0.0001), IVH incidence rate (OR = 0.40, 95% CI: 0.17∼0.95; Z = 2.08, P = 0.04), neonatal mortality (OR = 0.25, 95% CI: 0.13∼0.46; Z = 4.39, P < 0.0001), and proportion of neonates with birth weight < 1,500 g (OR = 0.45, 95% CI: 0.32∼0.64; Z = 4.50, P < 0.0001).

Conclusion

Vaginal progesterone lowered the incidences of preterm birth and adverse pregnancy outcomes in women with singleton pregnancies and a short cervix.

Recent Advances and Challenges in the Early Diagnosis and Treatment of Preterm Labor

Preterm birth (PTB) is the primary cause of neonatal mortality and long-term disabilities. The unknown mechanism behind PTB makes diagnosis difficult, yet early detection is necessary for controlling and averting related consequences. The primary focus of this work is to provide an overview of the known risk factors associated with preterm labor and the conventional and advanced procedures for early detection of PTB, including multi-omics and artificial intelligence/machine learning (AI/ML)- based approaches. It also discusses the principles of detecting various proteomic biomarkers based on lateral flow immunoassay and microfluidic chips, along with the commercially available point-of-care testing (POCT) devices and associated challenges. After briefing the therapeutic and preventive measures of PTB, this review summarizes with an outlook.

Challenges in Using Progestin to Prevent Singleton Preterm Births: Current Knowledge and Clinical Advice

Preterm birth is the leading cause of infant morbidity and mortality in children younger than 5 years old and accounts for approximately 35% of newborn deaths worldwide. The use of progestogen therapy for prevention of preterm birth has been one of the most controversial topics in modern obstetrics. Progestogens can be classified as natural or synthetic. Progesterone is a natural progestogen while progestins such as 17-alpha-hydroxyprogesterone caproate (17OHP-C) are synthetic steroid hormones. Evidence supporting the use of progestogens varies by formulation and populations studied. After more than a decade, the US Food and Drug Administration has withdrawn accelerated approval of 17OHP-C for the prevention of recurrent preterm birth in pregnant individuals with a singleton gestation. With this decision, there is no current FDA-approved treatment for prevention of spontaneous preterm birth. In this review, we provide a historical context behind the rise and fall of 17OHP-C clinical application, highlight the challenges behind the data supporting progestogen use, and offer suggestions on how to make an impact on preterm birth moving forward.

Screening vs. no screening for preterm delivery in low-risk singleton pregnancies: comparison by propensity score analysis

PURPOSE

To compare the effect of a policy of screening for spontaneous preterm delivery (SPD) by transvaginal cervical length (CL) measurement versus a no screening policy in the prevention of severe prematurity.

METHODS

Retrospective study on low-risk singleton pregnancies examined at 20-24 weeks. Two cohorts, one with SPD screening and the other without screening, were matched using propensity analysis to create the study groups. Women with short CL were treated with vaginal progesterone and/or cervical cerclage/pessary. The outcomes examined were SPD < 32 weeks (SPD 32) and SPD between 20 and 32 weeks (SPD 20-32).

RESULTS

Screening for SPD was associated with a significant reduction in the rate of SPD at less than 32 weeks (0.3 vs. 0.8%, p = 0.001 in the screened and no screened pregnancies, respectively) and in the rate of SPD 20-32 (0.3 vs. 0.9%, p = 0.005 in the screened and no screened pregnancies, respectively). After adjusting for maternal age, parity, body mass index, smoking and mode of conception, the screening group had significantly lower hazard for SPD 20-32 (HR = 0.36, 95% CI: 0.18-0.75, p = 0.006) and SPD32 (HR = 0.39, 95% CI: 0.19-0.82, p = 0.013).

CONCLUSION

Screening for SPD by transvaginal CL measurement in mid-pregnancy may reduce the incidence of severe prematurity in low-risk singleton pregnancies.

The Hassan Neonatal Morbidity Composite Scale and Neonatal Length of Stay-A Validation Study

OBJECTIVE

Obstetric studies often report neonatal morbidity as a composite score. Composite scores can simplify data analysis when multiple outcomes of interest are present and allows researchers to conduct smaller, more manageable trials. The Hassan scale is a neonatal morbidity composite scale that assigns high scores to infants with multiple morbidities and low scores to infants without or with single morbidities. The objective of this study was to validate the association between scores on the Hassan scale and neonatal intensive care unit (NICU) length of stay STUDY DESIGN:  We conducted a cohort study of all infants born between 22 and 366/7 weeks' gestation and cared for within 419 neonatal units in the Pediatrix Medical Group between 1997 and 2018. Each infant was assigned a Hassan's score based on the number of neonatal morbidity events that occurred during the delivery hospitalization. The association between Hassan's scores and neonatal length of stay was evaluated using linear regression. Multivariable models were constructed to determine if the Hassan score was independently associated with neonatal length of stay.

RESULTS

There were 760,037 infants included. The median (interquartile range [IQR]) gestational age of delivery was 34 (31, 35) weeks and the median (IQR) birth weight at delivery was 2,000 (1,503, 2,430) g. The median length of stay for infants discharged home was 17 (10-33) days. A Hassan's score was able to be assigned to 699,206 (92%) patients. Neonatal morbidities included in the Hassan scale were more common among infants born earlier in gestation. On adjusted analysis, the Hassan scale was found to be independently associated with neonatal length of stay (p < 0.001, coefficient = 10.4 days [95% confidence interval (CI): 10.3, 10.4 days]) with higher scores associated with longer lengths of stay.

CONCLUSION

The Hassan scale, more than a binary composite score, is able to differentiate preterm infants with prolonged hospitalizations from those with short hospitalizations.

KEY POINTS

· The Hassan scale is an independent predictor of neonatal length of stay.. · Classification of infants based on number of morbidities correlates with neonatal length of stay.. · The Hassan scale provided better discrimination than binary composite morbidity scores.. · The Hassan scale may be an economic predictor of health-related costs..

Pregnant Populations which Benefit from Vaginal Progesterone for Preventing Preterm Birth at <34 Weeks and Neonatal Morbidities: A Systematic Review and Meta-analysis

This study aimed to assess vaginal progesterone's effect on different populations and performed comparation between women with varied risk factors. Embase, PubMed, Cochrane library (CENTRAL) were searched without restriction to language up to February 25, 2021. Randomized controlled trials (RCTs) assessing vaginal progesterone administered to women at risk of preterm birth at <37 weeks. Two reviewers independently extracted data, and pooled relative risk (RR) with 95% confidence intervals (CIs) was calculated as well. Women with short cervix have a significantly lower risk of preterm birth at <34 weeks (pooled RR = 0.65; 95% CI: 0.55-0.77; I 2 = 0; p < 0.001; nine studies) and some neonatal morbidities; interaction tests showed that effect of vaginal progesterone differs significantly between women with short cervix and those with other risk factors (history of preterm birth, exclusive twin gestation, and vaginal bleeding). Evidences of this study showed that singleton gestations, as well as women with short cervix, benefit from vaginal progesterone in preventing preterm birth at <34 weeks and some neonatal morbidities. Women with short cervix are populations who benefit the most among other risk populations. KEY POINTS: · Vaginal progesterone reduces preterm birth and neonatal morbidities.. · Vaginal progesterone effects on some specific populations.. · Women with short cervix benefit the most..

Addressing a broken drug pipeline for preterm birth: why early preterm birth is an orphan disease

Preterm birth remains one of the most urgent unresolved medical problems in obstetrics, yet only 2 therapeutics for preventing preterm birth have ever been approved by the United States Food and Drug Administration, and neither remains on the market. The recent withdrawal of 17-hydroxyprogesterone caproate (17-OHPC, Makena) marks a new but familiar era for obstetrics with no Food and Drug Administration-approved pharmaceuticals to address preterm birth. The lack of pharmaceuticals reflects a broad and ineffective pipeline hindered by extensive regulatory hurdles, soaring costs of performing drug research, and concerns regarding adverse effects among a particularly vulnerable population. The pharmaceutical industry has historically limited investments in research for diseases with similarly small markets, such as cystic fibrosis, given their rarity and diminished projected financial return. The Orphan Drug Act, however, incentivizes drug development for "orphan diseases", defined as affecting <200,000 people in the United States annually. Although the total number of preterm births in the United States exceeds this threshold annually, the early subset of preterm birth (<34 weeks' gestation) would qualify, which is predominantly caused by inflammation and infection. The scientific rationale for classifying preterm birth into early and late subsets is strong given that their etiologies differ, and therapeutics that may be efficacious for one subset may not work for the other. For example, antiinflammatory therapeutics would be expected to be highly effective for early but not late preterm birth. A robust therapeutic pipeline of antiinflammatory drugs already exists, which could be used to target spontaneous early preterm birth, in combination with antibiotics shown to sterilize the amniotic cavity. New applications for therapeutics targeting spontaneous early preterm birth could categorize as orphan disease drugs, which could revitalize the preterm birth therapeutic pipeline. Herein, we describe why drugs targeting early preterm birth should qualify for orphan status, which may increase pharmaceutical interest for this vitally important obstetrical condition.

Assessment of different sonographic cervical measures to predict labor induction outcomes: a systematic review and meta-analysis

Background

Induction of labor (IOL) is a common obstetric approach to start or encourage uterine contractions to achieve a vaginal birth. It is recommended when continuing the pregnancy may be more dangerous for the mother or baby. Different ultrasonographic measures, such as cervical length, have been investigated as possible predictors of the outcomes of IOL. This meta-analysis aimed to assess the accuracy of ultrasound measurements in anticipating successful IOL.

Methods

The study conducted a thorough search on three databases (PubMed, Scopus, and Web of Science) until 04 March 2023, to find clinical studies published in English that reported different sonographic cervical measures and their ability to predict IOL outcomes. The chosen studies were stratified based on the type of indicator reported, and a meta-analysis was conducted to determine the best indicator for both successful and failed induction. The risk of bias and concerns about the applicability of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) method.

Results

This study analyzed 57 studies with 9,338 patients. Cervical length is moderately effective in predicting successful IOL, with pooled sensitivity (SN) and specificity (SP) of 0.67 and 0.70, respectively. However, cervical length had a pooled SN and SP of 0.70 and 0.61 for predicting failed IOL. The posterior cervical angle was found to have a higher pooled SN and SP of 0.79 and 0.73 for predicting successful IOL. Fetal head-perineum distance demonstrated moderate accuracy with a pooled SN, SP, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve of 0.58, 0.66, 1.95, 0.36, 5.33, and 0.9992, respectively, for predicting successful IOL.

Conclusions

Fetal head-perineum distance was the most effective predictor for successful IOL compared to cervical length, which only had a moderate predictive ability. Shortening of cervical length was not a useful indicator for successful IOL. On the other hand, the posterior cervical angle was the most reliable factor for predicting failed induction. The study's findings can aid in developing more effective management strategies for IOL.

Nanotechnological approaches for the treatment of placental dysfunction: recent trends and future perspectives

The transitory placenta develops during pregnancy and mediates the blood flow between the mother and the developing baby. Placental dysfunction, including but not limited to placenta accreta spectrum, fetal growth restriction, preeclampsia and gestational trophoblastic disease, arises from abnormal placental development and can result in significant adverse maternal and fetal health outcomes. Unfortunately, there is a lack of treatment alternatives for these disorders. Nanocarriers offer versatility, including extended circulation, organ-specific targeting and intracellular transport, finely tuning therapeutic placental interactions. This thorough review explores nanotechnological strategies for addressing placental disorders, encompassing dysfunction insights, potential drug-delivery targets and recent strides in placenta-targeted nanoparticle (NP) therapies, instilling hope for effective placental malfunction treatment.

A cross-sectional survey of women's views and preferences for preterm birth screening and treatment

OBJECTIVES

Primary outcomes were to determine; 1) the desire for more patient information from healthcare professionals on preterm birth (PTB) prevention 2) the desire for PTB screening surveillance or participation in research or 3) the acceptability of transvaginal ultrasound (TVUS) or vaginal examinations to predict spontaneous PTB.

METHODS

A 19-question, piloted, self-administered survey was completed by unselected pregnant women in a tertiary maternity hospital in Dublin, Ireland. Data was collected to include maternal socio-demographics, past obstetric history, and current pregnancy details, in addition to views and preferences on PTB screening and preventative treatments. Statistical analysis to include binary and multinomial regression was performed by IBM SPSS Statistics for Windows (Version 29.0).

RESULTS

277 women completed the study survey. 9.4% of women had attended the preterm birth surveillance clinic (PSC). 75.1% of respondents indicated a preference for more information from healthcare professionals about PTB. 65% reported that TVUS and vaginal examinations were acceptable in pregnancy. The acceptability of antenatal examinations was significantly influenced by ethnicity; white European (OR 2.58, CI 1.12-5.95, p = 0.003) and Asian (OR 3.39, CI 1.18-9.67, p = 0.02). Discomfort (25.3%) and vaginal bleeding (11.9%) were the most frequently reported concerns about TVUS. 95.7% of unselected women indicated that they would accept treatment to prevent PTB. Vaginal progesterone (53.8%) was preferred treatment compared to cervical cerclage (15.9%) or cervical pessary (16.6%). 55.6% of respondents stated they attend or wish to attend for additional appointments or research opportunities for PTB screening. Women with a previous PTB or second trimester miscarriage were more likely to attend or wish to attend for PTB screening (OR 3.23, CI 1.34-7.79, p = 0.009).

CONCLUSION

PTB is an important healthcare priority for pregnant women in Ireland. However, women require more information, counselling and reassurance about the utility and safety of TVUS in PSCs.

Progesterone control of myometrial contractility

During pregnancy, the primary function of the uterus is to be quiescent and not contract, which allows the growing fetus to develop and mature. A uterine muscle layer, myometrium, is composed of smooth muscle cells (SMCs). Before the onset of labor contractions, the uterine SMCs experience a complex biochemical and molecular transformation involving the expression of contraction-associated proteins. Labor is initiated when genes in SMCs are activated in response to a combination of hormonal, inflammatory and mechanical signals. In this review, we provide an overview of molecular mechanisms regulating the process of parturition in humans, focusing on the hormonal control of the myometrium, particularly the steroid hormone progesterone. The primary reason for discussing the regulation of myometrial contractility by progesterone is the importance of the clinical problem of preterm birth. It is thought that the hormonal mechanisms regulating premature uterine contractions represent an untimely triggering of the normal events occurring during term parturition. Yet, our knowledge of the complex and redundant hormonal pathways controlling uterine contractile activity leading to delivery of the neonate remains incomplete. Finally, we introduce recent animal studies using a novel class of drugs, Selective Progesterone Receptor Modulators, targeting progesterone signaling to prevent premature myometrial contractions.

Prediction of Preterm Delivery among Low-risk Indian Pregnant Women: Discriminatory Power of Cervical Length, Serum Ferritin, and Serum Alpha-fetoprotein

Background

Around 80% of preterm births (PTBs) occur spontaneously. Various biomarkers are being evaluated to assess the possible role of chorioamniotic inflammation in PTBs.

Aim

The aim of this study was to establish the accuracy of serum bio-markers( cut off values of ferritin and alpha-fetoprotein [AFP] at midtrimester) along with cervical length [CL] assessment to predict preterm delivery among low-risk women.

Methods

Three hundred low-risk pregnant women attending the antenatal clinic of a tertiary health care facility were included and underwent CL measurement during mid-trimester by transvaginal ultrasonography and their serum levels of ferritin and AFP were recorded. All were followed up till delivery.

Results

Receptor-operated characteristic curves for ferritin, AFP, and CL were constructed. Area under curves and Youden Index calculated for each marker were very low (<0.5) which is statistically considered very poor for a screening test.

Conclusion

Serum ferritin and AFP together with CL measurement in the second trimester of pregnancy had poor discriminatory value in predicting preterm delivery among low-risk asymptomatic pregnant women.

Bioengineering and the cervix: The past, current, and future for addressing preterm birth

The uterine cervix plays two important but opposing roles during pregnancy - as a mechanical barrier that maintains the fetus for nine months and as a compliant structure that dilates to allow for the delivery of a baby. In some pregnancies, however, the cervix softens and dilates prematurely, leading to preterm birth. Bioengineers have addressed and continue to address the lack of reduction in preterm birth rates by developing novel technologies to diagnose, prevent, and understand premature cervical remodeling. This article highlights these existing and emerging technologies and concludes with open areas of research related to the cervix and preterm birth that bioengineers are currently well-positioned to address.

Prediction and Prevention of Preterm Birth: Secondary Analysis of a Randomized Intervention Trial

Our objective was to evaluate whether pregnancy is prolonged by the use of a proteomics-based maternal serum screening test followed by treatment interventions. This is a secondary analysis of the PREVENT-PTB randomized trial comparing screening with the PreTRM test versus no screening. The primary trial analysis found no significant between-group difference in the preterm birth rate. Rather than considering a dichotomous outcome (preterm versus term), we treated gestational age at birth as a continuous variable using survival analysis. We also evaluated between-group difference in NICU length of stay and duration of respiratory support. Results indicated that pregnancy was significantly prolonged in subjects screened with the PreTRM test compared to controls (adjusted hazard ratio 0.53, 95% confidence interval 0.36-0.78, p < 0.01). Newborns of screened subjects had significantly shorter NICU stays but no significant decrease in duration of respiratory support. In the PreTRM screen-positive group, interventions that were associated with pregnancy prolongation included care management and low-dose aspirin but not 17-hydroxyprogesterone caproate. We conclude that screening with the PreTRM test followed by interventions for screen-positive pregnancies may prolong pregnancy and reduce NICU LOS, but these observations need to be confirmed by additional research.

Cervical Pessary for Prevention of Preterm Birth in Individuals With a Short Cervix: The TOPS Randomized Clinical Trial

Importance

A short cervix as assessed by transvaginal ultrasound is an established risk factor for preterm birth. Study findings for a cervical pessary to prevent preterm delivery in singleton pregnancies with transvaginal ultrasound evidence of a short cervix have been conflicting.

Objective

To determine if cervical pessary placement decreases the risk of preterm birth or fetal death prior to 37 weeks among individuals with a short cervix.

Design, Setting, and Participants

We performed a multicenter, randomized, unmasked trial comparing a cervical pessary vs usual care from February 2017 through November 5, 2021, at 12 centers in the US. Study participants were nonlaboring individuals with a singleton pregnancy and a transvaginal ultrasound cervical length of 20 mm or less at gestations of 16 weeks 0 days through 23 weeks 6 days. Individuals with a prior spontaneous preterm birth were excluded.

Interventions

Participants were randomized 1:1 to receive either a cervical pessary placed by a trained clinician (n = 280) or usual care (n = 264). Use of vaginal progesterone was at the discretion of treating clinicians.

Main Outcome and Measures

The primary outcome was delivery or fetal death prior to 37 weeks.

Results

A total of 544 participants (64%) of a planned sample size of 850 were enrolled in the study (mean age, 29.5 years [SD, 6 years]). Following the third interim analysis, study recruitment was stopped due to concern for fetal or neonatal/infant death as well as for futility. Baseline characteristics were balanced between participants randomized to pessary and those randomized to usual care; 98.9% received vaginal progesterone. In an as-randomized analysis, the primary outcome occurred in 127 participants (45.5%) randomized to pessary and 127 (45.6%) randomized to usual care (relative risk, 1.00; 95% CI, 0.83-1.20). Fetal or neonatal/infant death occurred in 13.3% of those randomized to receive a pessary and in 6.8% of those randomized to receive usual care (relative risk, 1.94; 95% CI, 1.13-3.32).

Conclusions and Relevance

Cervical pessary in nonlaboring individuals with a singleton gestation and with a cervical length of 20 mm or less did not decrease the risk of preterm birth and was associated with a higher rate of fetal or neonatal/infant mortality.

Trial Registration

ClinicalTrials.gov Identifier: NCT02901626.

Comparing the efficacy of vaginal micronized progesterone gel and capsule for prevention of preterm birth in singleton pregnancies with short cervical length at midtrimester: an indirect comparison meta-analysis

Objective: To evaluate the effectiveness of vaginal progesterone in preventing preterm birth in women with a singleton gestation and short cervical length and to determine which of the two formulations, micronized progesterone vaginal capsule versus vaginal gel containing micronized progesterone, is more effective for preventing preterm birth. Data sources: A systematic search was performed in the following databases: EMBASE, PubMed (MEDLINE), The Cochrane Library, and the Clinical Trials Registry (clinicaltrials.gov). Study eligibility criteria: Randomized controlled trials (RCTs), prospective and retrospective observational studies were included. We searched for progesterone administration to prevent preterm birth in asymptomatic women with a shortened cervix (<25 mm) measured by ultrasound in the second trimester of singleton pregnancy. Study appraisal and synthesis methods: Assessments of the risk of bias of RCTs were performed by applying the Cochrane Collaboration's Risk of Bias Tool; non-randomized control trials were evaluated with the Newcastle-Ottawa Scale (NOS). The primary outcome was preterm birth ≤33 weeks of gestation. Pooled relative risks (RR) and 95% CI's were calculated for dichotomous outcomes. Heterogeneity of treatment effect was assessed with the I² statistic. We pooled results of the primary outcome for individual studies using a random-effect model. We then performed a network meta-analysis to pool indirect comparisons between the two formulations (gel vs capsule). This analysis was performed using the network meta-analysis package within the R environment. Results: Five studies met the inclusion criteria (4 RCTs, one cohort study) including 1,048 women. The meta-analysis demonstrated that vaginal micronized progesterone significantly reduces preterm birth risk, Risk Ratio = 0.63; 95% CI, 0.48-0.82; p = 0.0006; with no heterogeneity between the studies: I ² = 0%. In the network meta-analysis, no significant difference was demonstrated (OR = 0.85; 95% CI, 0.43-1.69) between the effect of the two formulations of vaginal micronized progesterone (vaginal gel versus vaginal capsules) on the risk of PTB. Conclusion: Vaginal progesterone is associated with a decreased risk of premature birth in women with a shortened cervix in the second trimester of pregnancy. No differences were found between vaginal micronized progesterone in gel or capsule formulations. Systematic Review Registration: PROSPERO, identifier CRD42020165198.

Evolutionary perspective of uteroplacental malperfusion: subjacent insult common to most pregnancy complications

Linked article: There is a comment on this article by Yagel et al. Click here to view the Correspondence.

Declining incidence of cerebral palsy in South Korea

Presuming that the incidence of cerebral palsy (CP) in Korea is decreasing due to medical advances, we analyzed the trends and risk factors of CP in changing circumstances. We identified all women who delivered a singleton between 2007 and 2015 using the Korea National Health Insurance (KNHI). Information on pregnancy and birth was obtained by linking the KNHI claims database and data from the national health-screening program for infants and children. The 4-years incidence of CP decreased significantly from 4.77 to 2.52 per 1000 babies during the study period. The multivariate analysis revealed that the risk of developing CP was 29.5 times higher in preterm infants born before 28 weeks of gestational age, 24.5 times higher in infants born between 28 and 34 weeks, and 4.5 times higher in infants born between 34 and 36 weeks, compared to full-term appropriate for age (2.5 ~ 4 kg of body weight) infants. 5.6 times higher in those with birth weight < 2500 g, and 3.8 times higher in pregnancies with polyhydramnios. Additionally, respiratory distress syndrome increased the risk of developing CP by 2.04 times, while necrotizing enterocolitis was associated with a 2.80-fold increased risk of CP. In Korea, the incidence of CP in singleton decreased from 2007 to 2015. We need to continue to focus on developing medical technologies for the early detection of high-risk neonates and minimizing brain damage to reduce the incidence rate of CP effectively.

The exciting potential for ChatGPT in obstetrics and gynecology

Natural language processing-the branch of artificial intelligence concerned with the interaction between computers and human language-has advanced markedly in recent years with the introduction of sophisticated deep-learning models. Improved performance in natural language processing tasks, such as text and speech processing, have fueled impressive demonstrations of these models' capabilities. Perhaps no demonstration has been more impactful to date than the introduction of the publicly available online chatbot ChatGPT in November 2022 by OpenAI, which is based on a natural language processing model known as a Generative Pretrained Transformer. Through a series of questions posed by the authors about obstetrics and gynecology to ChatGPT as prompts, we evaluated the model's ability to handle clinical-related queries. Its answers demonstrated that in its current form, ChatGPT can be valuable for users who want preliminary information about virtually any topic in the field. Because its educational role is still being defined, we must recognize its limitations. Although answers were generally eloquent, informed, and lacked a significant degree of mistakes or misinformation, we also observed evidence of its weaknesses. A significant drawback is that the data on which the model has been trained are apparently not readily updated. The specific model that was assessed here, seems to not reliably (if at all) source data from after 2021. Users of ChatGPT who expect data to be more up to date need to be aware of this drawback. An inability to cite sources or to truly understand what the user is asking suggests that it has the capability to mislead. Responsible use of models like ChatGPT will be important for ensuring that they work to help but not harm users seeking information on obstetrics and gynecology.

[Pelvic exam in gynecology and obstetrics: Guidelines for clinical practice]

OBJECTIVE

To provide guidelines for the pelvic clinical exam in gynecology and obstetrics.

MATERIAL AND METHODS

A multidisciplinary experts consensus committee of 45 experts was formed, including representatives of patients' associations and users of the health system. The entire guidelines process was conducted independently of any funding. The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized.

METHODS

The committee studied 40 questions within 4 fields for symptomatic or asymptomatic women (emergency conditions, gynecological consultation, gynecological diseases, obstetrics, and pregnancy). Each question was formulated in a PICO (Patients, Intervention, Comparison, Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® methodology.

RESULTS

The experts' synthesis work and the application of the GRADE method resulted in 27 recommendations. Among the formalized recommendations, 17 present a strong agreement, 7 a weak agreement and 3 an expert consensus agreement. Thirteen questions resulted in an absence of recommendation due to lack of evidence in the literature.

CONCLUSIONS

The need to perform clinical examination in gynecological and obstetrics patients was specified in 27 pre-defined situations based on scientific evidence. More research is required to investigate the benefit in other cases.

Maternal Infection and Preterm Birth: From Molecular Basis to Clinical Implications

As the leading cause of neonatal morbidity and mortality, preterm birth is recognized as a major public health concern around the world. The purpose of this review is to analyze the connection between infections and premature birth. Spontaneous preterm birth is commonly associated with intrauterine infection/inflammation. The overproduction of prostaglandins caused by the inflammation associated with an infection could lead to uterine contractions, contributing to preterm delivery. Many pathogens, particularly Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Gardnerella vaginalis, Ureaplasma urealyticum, Mycoplasma hominis, Actinomyces, Candida spp., and Streptococcus spp. have been related with premature delivery, chorioamnionitis, and sepsis of the neonate. Further research regarding the prevention of preterm delivery is required in order to develop effective preventive methods with the aim of reducing neonatal morbidity.