17-alpha-hydroxyprogesterone caproate for maintenance tocolysis: a systematic review and metaanalysis of randomized trials

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Randomized trial of screening for preterm birth in low-risk women - the preterm birth screening study

BACKGROUND

Preterm birth is a major cause of perinatal morbidity and mortality. It is unclear whether the introduction of a universal transvaginal ultrasound cervical length screening program in women at low risk for preterm delivery is associated with a reduction in the frequency of preterm birth.

OBJECTIVE

To test the hypothesis that the introduction of a midtrimester universal transvaginal ultrasound cervical length screening program in asymptomatic singleton pregnancies without prior preterm delivery would reduce the rate of preterm birth at <37 weeks of gestation.

STUDY DESIGN

This study was a multicenter nonblinded randomized trial of screening of asymptomatic singleton pregnancies without prior spontaneous preterm birth, who were randomized to either cervical length screening program (ie, intervention group) or no screening (ie, control group). Participants were randomized at the time of their routine anatomy scan between 18 0/7 and 23 6/7 weeks of gestation. Women randomized in the screening group received cervical length measurement. Those who were found to have cervical length ≤25 mm were offered 200 mg vaginal progesterone daily along with cervical pessary. The primary outcome was preterm birth at <37 weeks. The risk of primary outcome was quantified by the relative risk with 95% confidence interval, and was based on the intention-to-screen principle.

RESULTS

A total of 1334 asymptomatic women with singleton pregnancies and without prior preterm birth, were included in the trial. Out of the 675 women randomized in the transvaginal ultrasound cervical length screening group, 13 (1.9%) were found to have transvaginal ultrasound cervical length ≤25 mm during the screening. Preterm birth at <37 weeks of gestation occurred in 48 women in the transvaginal ultrasound cervical length screening group (7.5%), and 54 women in the control group (8.7%) (relative risk, 0.86; 95% confidence interval, 0.59-1.25). Women randomized in the transvaginal ultrasound cervical length screening group had no significant differences in the incidence of preterm birth at less than 34, 32, 30, 28, and 24 weeks of gestation.

CONCLUSION

The introduction of a universal transvaginal ultrasound cervical length screening program at 18 0/6 to 23 6/7 weeks of gestation in singleton pregnancies without prior spontaneous preterm birth, with treatment for those with cervical length ≤25 mm, did not result in significant lower incidence of preterm delivery than the incidence without the screening program.

Progestogen maintenance therapy for prolongation of pregnancy after an episode of preterm labour: A systematic review and meta-analysis

BACKGROUND

Evidence for progestogen maintenance therapy after an episode of preterm labour (PTL) is contradictory.

OBJECTIVES

To assess effectiveness of progestogen maintenance therapy after an episode of PTL.

SEARCH STRATEGY

An electronic search in Central Cochrane, Ovid Embase, Ovid Medline and clinical trial databases was performed.

SELECTION CRITERIA

Randomised controlled trials (RCT) investigating women between 16+0 and 37+0  weeks of gestation with an episode of PTL who were treated with progestogen maintenance therapy compared with a control group.

DATA COLLECTION AND ANALYSIS

Systematic review and meta-analysis were conducted. The primary outcome was latency time in days. Secondary neonatal and maternal outcomes are consistent with the core outcome set for preterm birth studies. Studies were extensively assessed for data trustworthiness (integrity) and risk of bias.

MAIN RESULTS

Thirteen RCT (1722 women) were included. Progestogen maintenance therapy demonstrated a longer latency time of 4.32 days compared with controls (mean difference [MD] 4.32, 95% CI 0.40-8.24) and neonates were born with a higher birthweight (MD 124.25 g, 95% CI 8.99-239.51). No differences were found for other perinatal outcomes. However, when analysing studies with low risk of bias only (five RCT, 591 women), a significantly longer latency time could not be shown (MD 2.44 days; 95% CI -4.55 to 9.42).

CONCLUSIONS

Progestogen maintenance therapy after PTL might have a modest effect on prolongation of latency time. When analysing low risk of bias studies only, this effect was not demonstrated. Validation through further research, preferably by an individual patient data meta-analysis is highly recommended.

Activity restriction for women with arrested preterm labor: a randomized controlled trial

BACKGROUND

In the past, some pregnant women have been recommended to be in activity restriction because of the presumed increased risk of preterm birth due to the increased release of catecholamines, which might stimulate myometrial activity, during exercise and aerobic activity.

OBJECTIVE

This study aimed to test the hypothesis that in women with singleton pregnancy and arrested preterm labor, activity restriction would reduce the rate of preterm birth at <37 weeks of gestation.

STUDY DESIGN

This was a parallel-group nonblinded randomized trial conducted at a single center in Italy. Eligible patients were those with a diagnosis of arrested preterm labor, defined as not delivering after 48 hours of hospitalization for threatened preterm labor, with transvaginal ultrasound cervical length ≤25 mm, no other symptoms of possible uterine contractions, and cervical dilatation <3 cm at pelvic examination. Inclusion criteria were singleton pregnancies between 24 0/7 and 33 6/7 weeks of gestation. Participants were randomized in a 1:1 ratio to either activity restriction at the time of discharge or no activity restriction. Women in the intervention group were recommended activity restriction, defined as the following: pelvic rest, prohibition of sexual activity, and reduction of work and/or nonwork activity. The primary endpoint was preterm birth at <37 weeks of gestation.

RESULTS

A total of 120 participants were included in the trial; 60 patients were enrolled in the activity restriction group and 60 in the control group. Preterm birth at <37 weeks of gestation occurred in 15 of 60 women (25.0%) in the activity restriction group and 23 of 60 women (38.3%) in the control group (relative risk, 0.65; 95% confidence interval, 0.38-1.12). There was no significant between-group difference in the incidence of preterm birth at <32 weeks and in neonatal outcomes, but the trial was not powered for these outcomes.

CONCLUSION

In singleton gestations with arrested preterm labor, activity restriction, including pelvic rest, prohibition of sexual activity, and reduction of work and/or nonwork activity, does not result in a lower rate of preterm birth at <37 weeks. Given the evidence on the lack of benefits, use of activity restriction in this population should be discouraged.

Progestogens for maintenance tocolysis in symptomatic women. A systematic review and meta-analysis

OBJECTIVE

Prevention of preterm birth (PTB) with progestogens after an episode of threatened preterm labour is still controversial. As different progestogens have distinct molecular structures and biological effects, we conducted a systematic review and pairwise meta-analysis to investigate the individual role played by 17-alpha-hydroxyprogesterone caproate (17-HP), vaginal progesterone (Vaginal P) and oral progesterone (Oral P).

METHODS

The search was performed in MEDLINE, ClinicalTrials.gov and the Cochrane Central Register of Controlled Trials (CENTRAL) up to 31 October 2021. Published RCTs comparing progestogens to placebo or no treatment for maintenance tocolysis were considered. We included women with singleton gestations, excluding quasi-randomized trials, studies on women with preterm premature rupture of membrane, or receiving maintenance tocolysis with other drugs. Primary outcomes were preterm birth (PTB) < 37 weeks' and < 34 weeks'. We assessed risk of bias and evaluated certainty of evidence with the GRADE approach.

RESULTS

Seventeen RCTs including 2152 women with singleton gestations were included. Twelve studies tested vaginal P, five 17-HP, and only 1 oral P. PTB < 34 weeks' did not differ among women receiving vaginal P (RR 1.21, 95%CI 0.91 to 1.61, 1077 participants, moderate certainty of evidence), or oral P (RR 0.89, 95%CI 0.38 to 2.10, 90 participants, low certainty of evidence) as opposed to placebo. Instead, 17-HP significantly reduced the outcome (RR 0.72, 95% CI 0.54 to 0.95, 450 participants, moderate certainty of evidence). PTB < 37 weeks' did not differ among women receiving vaginal P (RR 0.95, 95%CI 0.72 to 1.26, 8 studies, 1231 participants, moderate certainty of evidence) or 17-HP (RR 0.86, 95%CI 0.60 to 1.21, 450 participants, low certainty of evidence) when compared to placebo/no treatment. Instead, oral P significantly reduced the outcome (RR 0.58, 95% CI 0.36 to 0.93, 90 participants, low certainty of evidence).

CONCLUSIONS

With a moderate certainty of evidence, 17-HP prevents PTB < 34 weeks' gestation among women that remained undelivered after an episode of threatened preterm labour. However, data are insufficient to generate recommendations in clinical practice. In the same women, both 17-HP and vaginal P are ineffective in the prevention of PTB < 37 weeks'.

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

BACKGROUND

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

OBJECTIVES

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

DESIGN

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

DATA SOURCES

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

STUDY ELIGIBILITY CRITERIA

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

METHODS

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

RESULTS

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

CONCLUSION

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

Interventions to Prevent Bronchopulmonary Dysplasia in Preterm Neonates: An Umbrella Review of Systematic Reviews and Meta-analyses

IMPORTANCE

Bronchopulmonary dysplasia (BPD) has multifactorial etiology and long-term adverse consequences. An umbrella review enables the evaluation of multiple proposed interventions for the prevention of BPD.

OBJECTIVE

To summarize and assess the certainty of evidence of interventions proposed to decrease the risk of BPD from published systematic reviews.

DATA SOURCES

MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, and Web of Science were searched from inception until November 9, 2020.

STUDY SELECTION

Meta-analyses of randomized clinical trials comparing interventions in preterm neonates that included BPD as an outcome.

DATA EXTRACTION AND SYNTHESIS

Data extraction was performed in duplicate. Quality of systematic reviews was evaluated using Assessment of Multiple Systematic Reviews version 2, and certainty of evidence was assessed using Grading of Recommendation, Assessment, Development, and Evaluation.

MAIN OUTCOMES AND MEASURES

(1) BPD or mortality at 36 weeks' postmenstrual age (PMA) and (2) BPD at 36 weeks' PMA.

RESULTS

A total of 154 systematic reviews evaluating 251 comparisons were included, of which 110 (71.4%) were high-quality systematic reviews. High certainty of evidence from high-quality systematic reviews indicated that delivery room continuous positive airway pressure compared with intubation with or without routine surfactant (relative risk [RR], 0.80 [95% CI, 0.68-0.94]), early selective surfactant compared with delayed selective surfactant (RR, 0.83 [95% CI, 0.75-0.91]), early inhaled corticosteroids (RR, 0.86 [95% CI, 0.75-0.99]), early systemic hydrocortisone (RR, 0.90 [95% CI, 0.82-0.99]), avoiding endotracheal tube placement with delivery room continuous positive airway pressure and use of less invasive surfactant administration (RR, 0.90 [95% CI, 0.82-0.99]), and volume-targeted compared with pressure-limited ventilation (RR, 0.73 [95% CI, 0.59-0.89]) were associated with decreased risk of BPD or mortality at 36 weeks' PMA. Moderate to high certainty of evidence showed that inhaled nitric oxide, lower saturation targets (85%-89%), and vitamin A supplementation are associated with decreased risk of BPD at 36 weeks' PMA but not the competing outcome of BPD or mortality, indicating they may be associated with increased mortality.

CONCLUSIONS AND RELEVANCE

A multipronged approach of delivery room continuous positive airway pressure, early selective surfactant administration with less invasive surfactant administration, early hydrocortisone prophylaxis in high-risk neonates, inhaled corticosteroids, and volume-targeted ventilation for preterm neonates requiring invasive ventilation may decrease the combined risk of BPD or mortality at 36 weeks' PMA.

Developmental exposure to the synthetic progestin, 17α-hydroxyprogesterone caproate, disrupts the mesocortical serotonin pathway and alters impulsive decision-making in rats

The synthetic progestin, 17α-hydroxyprogesterone caproate (17-OHPC), is administered to women at risk for preterm birth during a critical period of fetal development for mesocortical pathways. Yet, little information is available regarding the potential effects of 17-OHPC on the developing fetal brain. In rat models, the mesocortical serotonin pathway is sensitive to progestins. Progesterone receptor (PR) is expressed in layer 3 pyramidal neurons of medial prefrontal cortex (mPFC) and in serotonergic neurons of the dorsal raphe. The present study tested the hypothesis that exposure to 17-OHPC during development disrupts serotonergic innervation of the mPFC in adolescence and impairs behavior mediated by this pathway in adulthood. Administration of 17-OHPC from postnatal days 1-14 decreased the density of SERT-ir fibers within superficial and deep layers and decreased the density of synaptophysin-ir boutons in all layers of prelimbic mPFC at postnatal day 28. In addition, rats exposed to 17-OHPC during development were less likely to make impulsive choices in the Delay Discounting task, choosing the larger, delayed reward more often than controls at moderate delay times. Interestingly, 17-OHPC exposed rats were more likely to fail to make any choice (i.e., increased omissions) compared to controls at longer delays, suggesting disruptions in decision-making. These results suggest that further investigation is warranted in the clinical use of 17-OHPC to better inform a risk/benefit analysis of progestin use in pregnancy.

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

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

The use of vaginal progesterone as a maintenance therapy in women with arrested preterm labor: a double-blind placebo-randomized controlled trial

Background: The efficacy of maintenance tocolytic therapy after successful arrest of preterm labor remains controversial. The purpose of this study was to evaluate the efficacy of 400 mg of daily vaginal progesterone (cyclogest) after successful parenteral tocolysis to increase latency period and improvement of neonatal outcomes in women with threatened preterm labor.Materials and methods: In this randomized, double-blind, placebo-controlled trial, 85 participants were randomly allocated to either 400 mg daily of vaginal progesterone (n = 45) or placebo (n = 40) until 34 weeks of gestation. The primary outcomes were the time until delivery (latency period) and cervical length after 1 week of treatment. Secondary outcome were GA on delivery, type of delivery, incidence of low birth weight, perinatal morbidity and mortality.Results: Longer mean latency until delivery (53.6 ± 16.8 versus 34.5 ± 12.9) days p = .0001; longer mean of gestational age on delivery (37.5 ± 2.2 versus 34.2 ± 2.1) weeks p = .0001; cervical length after 1 week of treatment (27.5 ± 5.5 versus 20.7 ± 3.1) mm p = .0001; low birth weight 12 (29.3%) versus 19 (57.6%) p = .01; and NICU admission 9 (22%) versus 15 (45.5%), were significantly different between the two groups. No significant differences were found between neonatal death 1 (2.4%) versus 2 (6.1%), p = .43; RDS 5 (12.2%) versus 8 (24.2%), p = .17; and need to mechanical ventilator 2 (5.4%) versus 6 (18.2%) p = .136, for the progesterone and placebo groups, respectively.Conclusion: Daily administration of 400 mg vaginal progesterone after successful parenteral tocolysis may increase latency preceding delivery and improves cervical shortening and neonatal outcome in women with preterm labor. Further confirmatory studies are warranted.

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

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

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

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

Intramuscular 17α-hydroxyprogesterone caproate to decrease preterm delivery in women with placenta praevia: a randomised controlled trial

We tested the hypothesis that 17α-hydroxyprogesterone caproate (17α-OHP-C) may decrease preterm delivery (PTD) in women with placenta praevia. This was a randomised controlled trial included 114 women with placenta praevia (between 24 and 28 weeks). They were randomly assigned to group I (17α-OHP-C) who received weekly injection of 17α-OHP-C (250 mg/IM) till completing 37 weeks' gestation or group II (Non 17α-OHP-C). The percentage of placenta praevia patients went into PTD in the 17α-OHP-C group was significantly less in comparison to the PTD in the Non 17α-OHP-C group (∼37% vs. 63.5%, p = .004). Furthermore, the mean gestational age was significantly longer (36.7 ± 0.7 vs. 34.9 ± 1.2 weeks, p < .000), the mean number of bleeding attacks was significantly less and the mean birth weight was significantly higher (2841 ± 159 vs. 2561 ± 168 g, p < .000). In conclusion, maintenance tocolysis with intramuscular 17α-OHP-C in placenta praevia women appears beneficial in decreasing the number of bleeding attacks, the percentage of PTD and the neonatal ICU admission.IMPACT STATEMENTWhat is already known on this subject? Over the last two decades, a large number of studies indicated that placenta praevia is a major risk factor for preterm labour and prematurity with its neonatal complications. Increasing caesarean section rates had proportionally increased the incidence of placenta praevia.What do the results of this study add? Up to now, the effective and safe tocolytic agent among these patients is not established. The results of this study (prospective, randomised and controlled with calculated sample size) added a considerable support for hydroxyprogesterone caproate as an effective, safe and cheap tocolytic agent with excellent patient compliance.What are the implications of these findings for clinical practice and/or further research? Our findings may prompt researchers to conduct a large multicentre study to evaluate the prophylactic use of hydroxyprogesterone caproate to decrease preterm labour due to placenta praevia.

Maintenance tocolysis: a reappraisal of clinical evidence

INTRODUCTION

Maintenance tocolysis, mostly defined as the continuation of tocolytic treatment beyond 48 h, remains a matter of debate. There is no sufficient evidence from randomized controlled trials, that maintenance tocolysis is able to prolong pregnancy significantly and to reduce severe neonatal morbidity and mortality. Hence, it is not recommended in current guidelines. On the contrary, maintenance tocolysis is commonly used in clinical practice and subject of current clinical-scientific investigations.

TOCOLYTICS FOR MAINTENANCE TREATMENT

None of the conventional tocolytics (beta-sympathomimetics, calcium-channel blockers, magnesium, cyclooxygenase inhibitors, and oxytocin receptor antagonists) have proven to be appropriate for maintenance treatment. Progesterone and 17-α-hydroxyprogesterone caproate have shown promising results in low-quality randomized trials, but not in high-quality studies.

DISCUSSION

Basically, the value of studies regarding maintenance tocolysis is limited by a considerable heterogeneity, its mostly low quality, significant differences in methodology as well as the inadequate statistical power due to the small number of women studied. So far, maintenance tocolysis is a case-by-case decision outweighing the benefits and harms of tocolytic treatment.

Cervical pessary for preventing preterm birth in twin pregnancies with maternal short cervix after an episode of threatened preterm labor: randomised controlled trial

BACKGROUND

No intervention has proved effective to date in reducing the spontaneous preterm birth rate in twin pregnancies following an episode of threatened preterm labor and with a short cervix remaining. This study was designed to ascertain whether cervical pessaries are useful in preventing spontaneous preterm birth in women with twin pregnancies and a short cervix remaining after a threatened preterm labor episode.

STUDY DESIGN

This open, randomized, controlled trial was conducted in 132 pregnant women who had not delivered 48 hours after a threatened preterm labor episode and had a short cervix remaining (≤20 mm between 24⁰ and 29⁶ weeks and ≤10 mm between 30⁰ and 33⁶ weeks). Patients were randomly assigned to cervical pessary (n = 67) or routine management (n = 65). The primary outcome was the spontaneous preterm birth rate before 34 weeks. Spontaneous preterm birth before 28 and 37 weeks and neonatal morbidity and mortality were also evaluated in an intention-to-treat analysis.

RESULTS

Significant differences were observed in the spontaneous preterm birth rate before 34 weeks between the pessary and routine management groups (11 of 67 [16.4%] in the pessary group vs 21 of 65 [32.3%] in the control group; relative risk, 0.51 [confidence interval, 0.27-0.97]; P = .03). No significant differences were observed in the preterm birth rate < 28 weeks or < 37 weeks between groups. The pessary group less frequently required readmission for new threatened preterm labor episodes (4 of 67 [5.6%] vs 14 of 65 [21.5%]; relative risk, 0.28 [confidence interval, 0.10-0.80]; P = .009). Significant reduction was observed in the number of neonates weighing less than 2500 g (17.9% [24 of 134] vs 70.8% [92 of 130]; relative risk, 0.25 [confidence interval, 0.15-0.43]; P < .0001).

CONCLUSION

Pessary use did significantly lower the spontaneous preterm birth rate before 34 weeks in twin pregnancies with maternal short cervix remaining after a threatened preterm labor episode. Pessary use also reduced the threatened preterm labor recurrence and neonates' weight less than 2500 g.

Progesterone - Effective for Tocolysis and Maintenance Treatment After Arrested Preterm Labour?: Critical Analysis of the Evidence

Numerous experimental studies indicate that natural progesterone, through various mechanisms, exerts an inhibitory effect on uterine contractility and sensitises the myometrium for tocolytics. It was therefore appropriate to investigate the possible benefits of oral/vaginal progesterone and the synthetic progesterone derivative 17-α-hydroxyprogesterone caproate, applied intramuscularly, in clinical studies on primary tocolysis, additively to established tocolytics ("adjunctive tocolysis") and as maintenance treatment after successful tocolysis in cases of threatened preterm birth. Three studies with a small number of cases do not yield any sufficient evidence for recommending progesterone/17-α-hydroxyprogesterone caproate as primary tocolysis in women with preterm labour. There is also no evidence that progesterone or 17-α-hydroxyprogesterone caproate combined with commonly used tocolytics leads to a prolongation of pregnancy and a significant decrease in the rate of preterm birth. The data on the use of progesterone as maintenance treatment is controversial. While randomised, controlled studies with low quality showed promising results, studies with high quality did not reveal any significant differences with regard to the rate of preterm birth < 37 weeks of gestation, the latency period until delivery and in the neonatal outcome between progesterone/17-α-hydroxyprogesterone caproate and placebo or no treatment. Significant differences in the methodology, the inclusion and outcome criteria, the mode of application and the dosages of the substances as well as the inadequate statistical power as a result of low numbers of cases make interpretation and comparability of the studies difficult. Therefore, well-designed randomised, placebo-controlled, double-blind studies with uniform primary outcome criteria are needed in order to clarify whether progesterone and via which route of administration and at which dosage is of clinical benefit for patients with manifest preterm contractions and as maintenance treatment after arrested preterm labour.

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

BACKGROUND

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

OBJECTIVE

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

CONCLUSION

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

Effects of progestogens in women with preterm premature rupture of membranes

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

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

RESULTS

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

CONCLUSION

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

Cervical pessary to reduce preterm birth <34 weeks of gestation after an episode of preterm labor and a short cervix: a randomized controlled trial

BACKGROUND

To date, no intervention has proved effective in reducing the spontaneous preterm birth rate in singleton pregnancies following an episode of threatened preterm labor and short cervix remaining.

OBJECTIVE

This study was designed to ascertain whether cervical pessaries could be useful in preventing spontaneous preterm birth in women with singleton pregnancies and a short cervix after a threatened preterm labor episode.

STUDY DESIGN

This open randomized controlled trial was conducted in 357 pregnant women (between 24⁰-33⁶ weeks) who had not delivered 48 hours after a threatened preterm labor episode and had a short cervix remaining (≤25 mm at 24⁰-29⁶ weeks; ≤15 mm at 30⁰-33⁶ weeks). Patients were randomly assigned to cervical pessary (179) or routine management (178). The primary outcome was the spontaneous preterm birth rate <34 weeks. Spontaneous preterm birth <28 and 37 weeks and neonatal morbidity and mortality were also evaluated in an intention-to-treat analysis.

RESULTS

No significant differences between the pessary and routine management groups were observed in the spontaneous preterm birth rate <34 weeks (19/177 [10.7%] in the pessary group vs 24/175 [13.7%] in the control group; relative risk, 0.78; 95% confidence interval, 0.45-1.38). Spontaneous preterm birth <37 weeks occurred less frequently in the pessary group (26/175 [14.7%] vs 44/175 [25.1%]; relative risk, 0.58; 95% confidence interval, 0.38-0.90; P = .01). Preterm premature rupture of membranes rate was significantly lower in pessary carriers (4/177 [2.3%] vs 14/175 [8.0%]; relative risk, 0.28; 95% confidence interval, 0.09-0.84; P = .01). The pessary group less frequently required readmission for new threatened preterm labor episodes (8/177 [4.5%] vs 35/175 [20.0%]; relative risk, 0.23; 95% confidence interval, 0.11-0.47; P < .0001). No serious adverse maternal events occurred; neonatal morbidity and mortality were similar in both groups.

CONCLUSION

Pessary use did not significantly lower the spontaneous preterm birth rate <34 weeks in women with a short cervix remaining after a threatened preterm labor episode but did significantly reduce the spontaneous preterm birth rate <37 weeks, threatened preterm labor recurrence, and the preterm premature rupture of membranes rate.

17OHP-C in patients with spontaneous preterm labor and intact membranes: is there an effect according to the presence of intra-amniotic inflammation?

PROBLEM

It is not known whether 17-alpha-hydroxyprogesterone caproate (17OHP-C) is effective for preventing preterm delivery with an episode of preterm labor (PTL) with or without intra-amniotic inflammation/infection.

METHODS OF STUDY

This was a retrospective cohort study. One hundred and seven PTL patients were selected and divided into a 17OHP-C group (use of 17OHP-C: n = 53) and a no-treatment group (no use of 17OHP-C: n = 54). Moreover, the patients were divided into three subgroups (subgroup A: without intra-amniotic inflammation, B: with mild intra-amniotic inflammation, and C: with severe intra-amniotic inflammation) according to their level of amniotic interleukin (IL)-8, and perinatal prognosis was analyzed.

RESULTS

Interval from admission to delivery (days) in the 17OHP-C group (76 [13-126], n = 34) was significantly longer than that in the no-treatment group (50 [8-104], n = 33; P = .012) in subgroup B. In cases without intra-amniotic microbes in subgroup B, a significant prolongation of gestational days was associated with the 17OHP-C group (79 [13-126], n = 25) compared with the no-treatment group (50 [8-104], n = 29; P = .029). However, there were no significant differences in subgroups A or C.

CONCLUSION

17OHP-C could prolong gestational period in limited PTL cases with sterile mild intra-amniotic inflammation.

Decrease in the incidence of threatened preterm labor after implementation of transvaginal ultrasound cervical length universal screening

BACKGROUND

It is unknown if universal second-trimester transvaginal ultrasound (TVU) cervical length (CL) screening in asymptomatic women with singleton gestations and no prior spontaneous preterm birth (SPTB) affects the incidence of symptoms of preterm labor (PTL) later in pregnancy.

OBJECTIVE

To evaluate the incidence of threatened PTL before and after the implementation of universal second trimester TVU CL screening.

STUDY DESIGN

This was a retrospective cohort study of all consecutive singleton gestations without prior SPTB presenting to obstetric triage for threatened PTL between 23 0/7 and 33 6/7 week in 2011 (1 January-31 December), and in 2014 (1 January-31 December) at Thomas Jefferson University Hospital (TJU) (Philadelphia, PA). These 2 years were chosen as a new protocol for universal TVU CL screening was started on 1 January 2012. This protocol involved one measurement of TVU CL in all singleton gestations without a prior SPTB at 18 0/7 - 23 6/7 week, the time of the "anatomy" scan. Women with prior SPTB were excluded from this study. The primary outcome included the incidence of threatened PTL, defined as the number of women with singleton gestations without prior SPTB who presented with threatened PTL to our labor and delivery (L&D) triage unit annually, divided by the total number of annual deliveries of women with singleton gestation without prior SPTB. Secondary outcomes were the incidence of PTL, defined as the number of women with singleton gestations without prior SPTB admitted for PTL annually divided by the total number of annual deliveries of women with singleton gestation and without prior SPTB; and length of stay in the hospital. We aimed to compare primary and secondary outcome in the "2011" versus the "2014" group.

RESULTS

In 2011, there were a total of 1745 deliveries at TJU, of which 1550 (88.8%) were singletons without prior SPTB. In 2014, there were a total of 1924 deliveries at TJU, 1751 (91.0%) were singletons without prior SPTB who were offered universal TVU CL screening. One hundred and seventy-two women with singletons without prior SPTB presented in L&D triage unit in 2011; and 118 women with singletons without prior SPTB presented in L&D triage unit in 2014. There were significant decreases in the incidence of threatened PTL from 11.1% (172/1550) in 2011 to 6.7% (118/1751) in 2014 (p < .001), as well as in the rate of admission for PTL from 2.3% (35/1550) to 1.4% (24/1751), respectively (p = .04). Length of stay was not significantly different between the two groups.

CONCLUSION

The introduction of a universal TVU CL screening program in women with singleton gestations without a history of SPTB is associated with a reduction in the frequency of threatened PTL and admission for PTL. Key Message The introduction of a second trimester universal transvaginal ultrasound (TVU) cervical length (CL) screening program in women without a history of spontaneous preterm birth (SPTB) is associated with a reduction in the incidence of threatened preterm labor (PTL) and admission for PTL.

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

IMPORTANCE

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

OBJECTIVE

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

DESIGN, SETTING, AND PARTICIPANTS

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

INTERVENTIONS

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

MAIN OUTCOMES AND MEASURES

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

RESULTS

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

CONCLUSIONS AND RELEVANCE

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

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02716909.

17-alpha hydroxyprogesterone caproate for preterm birth prevention: Where have we been, how did we get here, and where are we going?

Prematurity is a major public health problem in the United States and worldwide. Women with a history of a previous preterm birth are at high risk for recurrence. Progesterone is a key hormone involved in pregnancy maintenance. In general, progesterone is thought to maintain pregnancy through several closely linked mechanisms: (1) promotion of uterine quiescence, (2) inhibition of pro-inflammatory cells, and (3) immunosuppressive action. 17-Alpha hydroxyprogesterone caproate is currently the only medication approved to prevent recurrent preterm birth. The purpose of this review is to discuss the history of 17-alpha hydroxyprogesterone caproate use for recurrent preterm birth prevention, the rationale behind 17-alpha hydroxyprogesterone caproate administration, and current evidence-based indications for 17-alpha hydroxyprogesterone caproate use.

Risk of spontaneous preterm birth in IVF-conceived twin pregnancies

OBJECTIVE

To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester in screening for preterm birth in in vitro (IVF)-conceived twin pregnancies versus spontaneously-conceived twin pregnancies.

METHODS

This was a retrospective cohort study. Potential study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7 to 23 6/7-week gestation. All women with twin diamniotic pregnancies screened with a single TVU CL for this trial were included. Mean TVU CLs were compared between IVF-conceived twin pregnancies and spontaneously-conceived twin pregnancies. The relationship of TVU CL with gestational age at delivery was assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups. The primary outcome was the mean of TVU CL. Distribution of CL was determined and normality was examined in both groups Results: A total of 668 women with diamniotic twin pregnancies who underwent TVU CL screening between 18 0/6 and 23 6/7 weeks were included. 158 (23.7%) were IVF-conceived pregnancies, and 510 (76.3%) were spontaneously-conceived pregnancies. No women received progesterone, pessary, or cerclage for preterm birth prevention during pregnancy. The mean TVU CL was significantly lower in the IVF-conceived group (32.2 ± 10.5 mm) compared to the spontaneously-conceived group (34.1 ± 9.1 mm) (mean difference (MD) - 1.90 mm, 95%CI -3.72 to -0.08). The incidence of TVU CL ≤30 mm was 30.4% in the IVF-conceived group and 21.6% in the spontaneously-conceived group (adjusted odds ratio (aOR) 1.59, 95%CI 1.06-2.37). IVF-conceived twins had a significantly higher risk of spontaneous preterm birth <34 weeks (32.9 versus 21.2%; aOR 1.83, 95% confidence interval (CI) 1.23-2.71) and higher rate of delivery due to spontaneous onset of labor (64.5 versus 54.9%; aOR 1.50, 95%CI 1.03-2.17). For any given TVU CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for IVF-conceived twins was earlier by about 1 week on average compared with spontaneously-conceived twins.

CONCLUSIONS

The higher rate of spontaneous preterm birth in IVF-conceived twin pregnancies is predicted by lower midtrimester TVU CL, as well as by the lower gestational age at birth per any given CL in the IVF-conceived compared to the spontaneously-conceived twin pregnancies.

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

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

Progestogens for Maintenance Tocolysis in Women With a Short Cervix: A Randomized Controlled Trial

OBJECTIVE

To assess the efficacy of progestogens for maintenance tocolysis in women undelivered after their first preterm labor episode.

METHODS

Women with singleton pregnancies between 22 0/7 and 31 6/7 weeks of gestation with arrested preterm labor and a cervical length 25 mm or less at hospital discharge were eligible. Patients with a previous preterm birth were excluded. In a randomized controlled trial conducted in five university hospitals, women were randomized to receive vaginal progesterone (200 mg per day) or intramuscular 17α-hydroxyprogesterone caproate (341 mg per week) or to an observation groups (control group). The primary outcome was the proportion of women with preterm birth at less than 37 weeks of gestation. A sample size of 160 per group (n=480) was planned to compare vaginal progesterone and 17α-hydroxyprogesterone caproate groups with those in the control group. The sample size estimation was based on the hypothesis that the risk of experiencing preterm birth in the control group would be 30% and that 17α-hydroxyprogesterone caproate or progesterone would decrease this risk to 15%. A P value of <.025 was defined as statistically significant. At planned interim analysis (n=254), the trial was stopped for futility.

RESULTS

Between July 2010 and June 2015, 257 women were eligible and 254 were subsequently randomly assigned to vaginal progesterone (n=86), 17α-hydroxyprogesterone caproate (n=87), or observation (n=81). Nineteen (8%) were excluded from the analysis because they either dropped out or information was missing, leaving 235 women available for analysis. Demographic characteristics were similar across groups. The preterm birth rate did not differ significantly between groups: 23% in the 17α-hydroxyprogesterone caproate group, 39% in the vaginal progesterone group, and 22% in the women in the control group (P=.949 for 17α-hydroxyprogesterone caproate compared with the women in the control group and P=.027 for vaginal progesterone compared with women in the control group).

CONCLUSION

The use of progestogens for maintenance tocolysis in women with a short cervix did not reduce the rate of preterm birth.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01178788.

Interventions for treating hyperemesis gravidarum: a Cochrane systematic review and meta-analysis

INTRODUCTION

While nausea and vomiting in early pregnancy are very common, affecting approximately 80% of the pregnancies, hyperemesis gravidarum is a severe form affecting 0.3-1.0% of the pregnancies. Although hyperemesis gravidarum is rarely a source of mortality, it is a significant source of morbidity. It is one of the most common indications for hospitalization in pregnancy. Beyond the maternal and fetal consequences of malnutrition, the severity of hyperemesis symptoms causes a major psychosocial burden leading to depression, anxiety, and even pregnancy termination. The aim of this meta-analysis was to examine all randomized controlled trials of interventions specifically for hyperemesis gravidarum and evaluate them based on both subjective and objective measures of efficacy, maternal and fetal/neonatal safety, and economic costs.

MATERIAL AND METHODS

Randomized controlled trials were identified by searching electronic databases. We included all randomized controlled trials for the treatment of hyperemesis gravidarum. The primary outcome was intervention efficacy as defined by severity, reduction, or cessation in nausea/vomiting; number of episodes of emesis; and days of hospital admission. Secondary outcomes included other measures of intervention efficacy, adverse maternal/fetal/neonatal outcomes, quality of life measures, and economic costs.

RESULTS

Twenty-five trials (2052 women) met the inclusion criteria but the majority of 18 different comparisons described in the review include data from single studies with small numbers of participants. Selected comparisons reported below: No primary outcome data were available when acupuncture was compared with placebo. There was insufficient evidence to identify clear differences between acupuncture and metoclopramide in a study with 81 participants regarding reduction/cessation in nausea or vomiting (risk ratio (RR) 1.40, 95% CI 0.79-2.49 and RR 1.51, 95% CI 0.92-2.48, respectively). Midwife-led outpatient care was associated with fewer hours of hospital admission than routine inpatient admission (mean difference (MD) - 33.20, 95% CI -46.91 to -19.49) with no difference in pregnancy-unique quantification of emesis and nausea (PUQE) score, decision to terminate the pregnancy, miscarriage, small-for-gestational age infants, or time off work when compared with routine care. Women taking vitamin B6 had a slightly longer hospital stay compared with placebo (MD 0.80 days, 95% CI 0.08-1.52). There was insufficient evidence to demonstrate a difference in other outcomes including mean number of episodes of emesis (MD 0.50, 95% CI -0.40-1.40) or side effects. A comparison between metoclopramide and ondansetron identified no clear difference in the severity of nausea or vomiting (MD 1.70, 95% CI -0.15-3.55, and MD -0.10, 95% CI -1.63-1.43; one study, 83 women, respectively). However, more women taking metoclopramide complained of drowsiness and dry mouth (RR 2.40, 95% CI 1.23-4.69, and RR 2.38, 95% CI 1.10-5.11, respectively). There were no clear differences between groups for other side effects. In a single study with 146 participants comparing metoclopramide with promethazine, more women taking promethazine reported drowsiness, dizziness, and dystonia (risk ratio (RR) 0.70, 95% CI 0.56-0.87, RR 0.48, 95% CI 0.34-0.69, and RR 0.31, 95% CI 0.11-0.90, respectively). There were no clear differences between groups for other important outcomes including quality of life and other side effects. In a single trial with 30 women, those receiving ondansetron had no difference in duration of hospital admission compared to those receiving promethazine (mean difference (MD) 0.00, 95% CI -1.39-1.39), although there was increased sedation with promethazine (RR 0.06, 95% CI 0.00-0.94). Regarding corticosteroids, in a study with 110 participants there was no difference in days of hospital admission compared to placebo (MD -0.30, 95% CI -0.70-0.10), but there was a decreased readmission rate (RR 0.69, 95% CI 0.50-0.94; 4 studies, 269 women). For hydrocortisone compared with metoclopramide, no data were available for primary outcomes and there was no difference in the readmission rate (RR 0.08, 95% CI 0.00-1.28; one study, 40 women). In a study with 80 women, compared to promethazine, those receiving prednisolone had increased nausea at 48 h (RR 2.00, 95% CI 1.08-3.72), but not at 17 days (RR 0.81, 95% CI 0.58-1.15). There was no clear difference in the number of episodes of emesis or subjective improvement in nausea/vomiting.

CONCLUSIONS

While there were a wide range of interventions studied, both pharmaceutical and otherwise, there were a limited number of placebo controlled trials. In comparing the efficacy of the commonly used antiemetics, metoclopramide, ondansetron, and promethazine, the results of this review do not support the clear superiority of one over the other in symptomatic relief. Other factors such as side effect profile medication safety and healthcare costs should also be considered when selecting an intervention.

Administration of Progesterone Throughout Pregnancy Increases Maternal Steroids Without Adverse Effect on Mature Oligodendrocyte Immunostaining in the Guinea Pig

Progesterone is administered to pregnant women at risk of premature labor, despite systematic reviews showing conflicting outcomes regarding its use, highlighting doubt over the effectiveness of the therapy. Progesterone can be rapidly metabolized into a number of steroids, but to date, there has been a lack of investigation into the fetal steroid profiles following administration and whether this impacts fetal neurodevelopment. The objective of this study was to determine the effect of progesterone treatment on allopregnanolone and cortisol levels in the fetus and on a marker of myelination in the fetal brain. We used a guinea pig model where pregnant dams were administered vehicle (β-cyclodextrin) or progesterone orally throughout pregnancy (GA29-61). Maternal and fetal fluids and tissues were collected at both preterm (GA61) and term (GA68) ages. Maternal and fetal progesterone and cortisol were analyzed by enzyme immunoassay and allopregnanolone by radioimmunoassay. Measurement of myelination of fetal brains (hippocampus, cingulum, and subcortical white matter) at preterm and term ages was performed by immunohistochemistry staining for myelin basic protein. We found that dams receiving progesterone had significantly elevated progesterone and cortisol concentrations, but there was no effect on allopregnanolone. Interestingly, the increased cortisol concentrations were not reflected in the fetuses, and there was no effect of progesterone treatment on myelination. Therefore, we conclude that in our guinea pig model, maternal administration of progesterone has no effect on cortisol levels or markers of mature oligodendrocytes in the fetus and suggest this is potentially due to the protective cortisol barrier in the placenta.

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

OBJECTIVE

Randomized controlled trials (RCTs) have recently compared intramuscular 17α-hydroxyprogesterone caproate (17-OHPC) with vaginal progesterone for reducing the risk of spontaneous preterm birth (SPTB) in singleton gestations with prior SPTB. The aim of this systematic review and meta-analysis was to evaluate the efficacy of vaginal progesterone compared with 17-OHPC in prevention of SPTB in singleton gestations with prior SPTB.

METHODS

Searches of electronic databases were performed to identify all RCTs of asymptomatic singleton gestations with prior SPTB that were randomized to prophylactic treatment with either vaginal progesterone (intervention group) or intramuscular 17-OHPC (comparison group). No restrictions for language or geographic location were applied. The primary outcome was SPTB < 34 weeks. Secondary outcomes were SPTB < 37 weeks, < 32 weeks, < 28 weeks and < 24 weeks, maternal adverse drug reaction and neonatal outcomes. The summary measures were reported as relative risk (RR) with 95% CI. Risk of bias for each included study was assessed.

RESULTS

Three RCTs (680 women) were included. The mean gestational age at randomization was about 16 weeks. Women were given progesterone until 36 weeks or delivery. Regarding vaginal progesterone, one study used 90 mg gel daily, one used 100 mg suppository daily and one used 200 mg suppository daily. All included RCTs used 250 mg intramuscular 17-OHPC weekly in the comparison group. Women who received vaginal progesterone had significantly lower rates of SPTB < 34 weeks (17.5% vs 25.0%; RR, 0.71 (95% CI, 0.53-0.95); low quality of evidence) and < 32 weeks (8.9% vs 14.5%; RR, 0.62 (95% CI, 0.40-0.94); low quality of evidence) compared with women who received 17-OHPC. There were no significant differences in the rates of SPTB < 37 weeks, < 28 weeks and < 24 weeks. The rate of women who reported adverse drug reactions was significantly lower in the vaginal progesterone group compared with the 17-OHPC group (7.1% vs 13.2%; RR, 0.53 (95% CI, 0.31-0.91); very low quality of evidence). Regarding neonatal outcomes, vaginal progesterone was associated with a lower rate of neonatal intensive care unit admission compared with 17-OHPC (18.7% vs 23.5%; RR, 0.63 (95% CI, 0.47-0.83); low quality of evidence). For the comparison of 17-OHPC vs vaginal progesterone, the quality of evidence was downgraded for all outcomes by at least one degree due to imprecision (the optimal information size was not reached) and by at least one degree due to indirectness (different interventions).

CONCLUSIONS

Daily vaginal progesterone (either suppository or gel) started at about 16 weeks' gestation is a reasonable, if not better, alternative to weekly 17-OHPC injection for prevention of SPTB in women with singleton gestations and prior SPTB. However, the quality level of the summary estimates was low or very low as assessed by GRADE, indicating that the true effect may be, or is likely to be, substantially different from the estimate of the effect. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. COMPARACIÓN ENTRE LA PROGESTERONA VAGINAL Y EL 17Α-HIDROXIPROGESTERONA CAPROATO INTRAMUSCULAR PARA LA PREVENCIÓN DEL PARTO PRETÉRMINO ESPONTÁNEO RECURRENTE EN EMBARAZOS CON FETO ÚNICO: REVISIÓN SISTEMÁTICA Y METAANÁLISIS DE ENSAYOS CONTROLADOS ALEATORIOS: RESUMEN OBJETIVO: Recientemente se han realizado varios ensayos controlados aleatorios (ECA) que comparaban el caproato de 17α-hidroxiprogesterona (17-OHPC, por sus siglas en inglés) por vía intramuscular con la progesterona por vía vaginal para la reducción del riesgo de parto pretérmino espontáneo (PPTE) en embarazos con feto único de gestantes con historial de PPTE. El objetivo de esta revisión sistemática y metaanálisis fue evaluar la eficacia de la progesterona vaginal en comparación con la 17-OHPC en la prevención de embarazos con feto único de gestantes con historial de PPTE. MÉTODOS: Se realizaron búsquedas en bases de datos electrónicas para identificar todos los ECA con embarazos de feto único asintomáticos con historial de PPTE antes de ser asignados al azar a un tratamiento profiláctico, ya fuera con progesterona vaginal (grupo de intervención) o con 17-OHPC intramuscular (grupo de control). No se aplicaron restricciones respecto al idioma o la ubicación geográfica. El resultado primario fue PPTE < 34 semanas. Los resultados secundarios fueron PPTE <37 semanas, < 32 semanas, < 28 semanas y < 24 semanas, la reacción materna adversa al fármaco y los resultados neonatales. Las medidas del resumen se reportaron como riesgo relativo (RR) con IC del 95%. Para cada estudio incluido se evaluó el riesgo de sesgo.

RESULTADOS

Se incluyeron tres ECA (680 mujeres). La media de la edad gestacional en el momento de la aleatorización fue de 16 semanas. A las mujeres se les administró progesterona hasta la semana 36 o hasta el parto. Con respecto a la progesterona vaginal, un estudio utilizó gel de 90 mg diariamente, otro utilizó un supositorio diario de 100 mg y el otro utilizó un supositorio diario de 200 mg. Todos los ECA incluidos en el grupo de comparación utilizaron 250 mg semanales de 17-OHPC por vía intramuscular. Las mujeres que recibieron progesterona vaginal tuvieron tasas significativamente más bajas de PPTE < 34 semanas (17,5% vs. 25,0%; RR 0,71 (IC 95%, 0,53-0,95); calidad de la evidencia baja) y < 32 semanas (8,9% vs. 14,5%; RR 0,62 (IC 95%, 0,40-0,94); calidad de evidencia baja), en comparación con las mujeres que recibieron 17-OHPC. No hubo diferencias significativas en las tasas de PPTE < 37 semanas, < 28 semanas y < 24 semanas. La tasa de mujeres que reportaron reacciones adversas a los medicamentos fue significativamente menor en el grupo de progesterona vaginal en comparación con el grupo de 17-OHPC (7,1% vs. 13,2%; RR 0,53 (IC 95%, 0,31-0,91); calidad de la evidencia muy baja). En cuanto a los resultados neonatales, la progesterona vaginal se asoció a una menor tasa de admisiones en la unidad neonatal de cuidados intensivos en comparación con la 17-OHPC (18,7% vs. 23,5%; RR 0,63 (IC 95%, 0,47-0,83); calidad de evidencia baja). Para la comparación del 17-OHPC con la progesterona vaginal se rebajó la calidad de las pruebas para todos los resultados en al menos un grado debido a imprecisiones (no se alcanzó el tamaño óptimo de la información) y en al menos un grado debido al carácter indirecto de los estudios (diferentes intervenciones).

CONCLUSIONES

La progesterona vaginal administrada diariamente (ya fuera como supositorio o como gel) desde la semana 16 de gestación es una alternativa razonable, si no mejor, a una inyección semanal de 17-OHPC para la prevención de PPTE en mujeres con embarazos de feto único e historial de PPTE. Sin embargo, el nivel de calidad de las estimaciones del resumen fue bajo o muy bajo según lo evaluado por GRADE, lo que indica que el verdadero efecto puede ser, o es probable que sea, sustancialmente diferente de la estimación del efecto. 17Α-:META: : (randomized controlled trials,RCTs)(spontaneous preterm birth,SPTB)17α-(intramuscular 17α-hydroxyprogesterone caproate,17-OHPC)SPTB。metaSPTB17-OHPCSPTB。 : ,SPTBRCTs,RCTs()17-OHPC()。。34SPTB。37、32、2824SPTB,。(relative risk,RR)95%CI。。 : 3RCTs(680)。16。,36。,90 mg,100 mg,200 mg。,RCTs250 mg 17-OHPC。17-OHPC,34 [17.5%25.0%;RR,0.71(95% CI,0.53 ~ 0.95);]32[8.9%14.5%;RR,0.62(95% CI,0.40 ~ 0.94);]SPTB。37、2824SPTB。17-OHPC,[7.1%13.2%;RR,0.53(95% CI,0.31 ~ 0.91);]。,17-OHPC,[18.7%23.5%;RR,0.63(95% CI,0.47 ~ 0.83);]。17-OHPC,(),()。 : SPTBSPTB,16()17-OHPC,。,GRADE,,。.

Effect of partial compliance on the prevention of recurrent preterm birth in women receiving weekly 17 alpha-hydroxyprogesterone caproate injections

PURPOSE

To analyze the effect of partial compliance on preterm birth (PTB) prevention among women with previous PTB and receiving 17 alpha-hydroxyprogesterone caproate (17-OHPC).

STUDY DESIGN

This is a secondary analysis of a multicenter trial for the prevention of recurrent PTB. Women with prior PTB were randomly assigned between 15 0/7 and 20 3/7 weeks to weekly injections of either 17-OHPC or placebo. Full 100% compliance (group 1) was compared to 40-80% (group 2). Recurrent PTB rates and odds ratios were calculated. Student's t, Chi-square, Wilcoxon Rank-Sum, multivariate logistic regression and Breslow-Day tests were used.

RESULTS

Group 1 included 370 women versus 35 in group 2. In each group, the PTB rate was significantly reduced in pregnancies receiving 17-OHPC compared to placebo. The adjusted odds ratio for PTB rate in group 1 was 0.48 (95% CI 0.31-0.75) versus 0.18 (95% CI 0.04-0.92) in group 2. Comparing the homogeneity of both odds ratios, the rates of recurrent PTB prevention in both groups were not statistically different (Breslow-Day test; p= .15).

CONCLUSION

A compliance rate of 40-80% did not significantly reduce 17-OHPC's efficacy. If confirmed, our findings could lead to a dramatic decrease in costs related to prevention of recurrent PTB.

Supplementation with progestogens in the first trimester of pregnancy to prevent miscarriage in women with unexplained recurrent miscarriage: a systematic review and meta-analysis of randomized, controlled trials

OBJECTIVE

To investigate whether treatment with progestogens in the first trimester of pregnancy would decrease the incidence of miscarriage in women with a history of unexplained recurrent miscarriage.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Women with a history of unexplained recurrent miscarriage.

INTERVENTION(S)

Randomized, controlled trials were identified by searching electronic databases. We included randomized, controlled trials comparing supplementation with progestogens (i.e., intervention group) in the first trimester of pregnancy with control (either placebo or no treatment) in women with a history of recurrent miscarriage. All types of progestogens, including natural P and synthetic progestins, were analyzed.

MAIN OUTCOME MEASURE(S)

The primary outcome was the incidence of miscarriage. The summary measures were reported as relative risk (RR) with 95% confidence interval (CI).

RESULT(S)

Ten trials including 1,586 women with recurrent miscarriage were analyzed. Eight studies used placebo as control and were double-blind. Regarding the intervention, two RCTs used natural P, whereas the other eight studies used progestins: medroxyprogesterone, cyclopentylenol ether of progesterone, dydrogesterone, or 17-hydroxyprogesterone caproate. Pooled data from the 10 trials showed that women with a history of unexplained recurrent miscarriage who were randomized to the progestogens group in the first trimester and before 16 weeks had a lower risk of recurrent miscarriage (RR 0.72, 95% CI 0.53-0.97) and higher live birth rate (RR 1.07, 95% CI 1.02-1.15) compared with those who did not. No statistically significant differences were found in the other secondary outcomes, including preterm birth (RR 1.09, 95% CI 0.71-1.66), neonatal mortality (RR 1.80, 95% CI 0.44-7.34), and fetal genital abnormalities (RR 1.68, 95% CI 0.22-12.62).

CONCLUSION(S)

Our findings provide evidence that supplementation with progestogens may reduce the incidence of recurrent miscarriages and seem to be safe for the fetuses. Synthetic progestogens, including weekly IM 17-hydroxyprogesterone caproate, but not natural P, were associated with a lower risk of recurrent miscarriage. Given the limitations of the studies included in our meta-analysis, it is difficult to recommend route and dose of progestogen therapy. Further head-to-head trials of P types, dosing, and route of administration are required.

Uterotonic Neuromedin U Receptor 2 and Its Ligands Are Upregulated by Inflammation in Mice and Humans, and Elicit Preterm Birth

Uterine labor requires the conversion of a quiescent (propregnancy) uterus into an activated (prolabor) uterus, with increased sensitivity to endogenous uterotonic molecules. This activation is induced by stressors, particularly inflammation in term and preterm labor. Neuromedin U (NmU) is a neuropeptide known for its uterocontractile effects in rodents. The objective of the study was to assess the expression and function of neuromedin U receptor 2 (NmU-R2) and its ligands NmU and the more potent neuromedin S (NmS) in gestational tissues, and the possible implication of inflammatory stressors in triggering this system. Our data show that NmU and NmS are uterotonic ex vivo in murine tissue, and they dose-dependently trigger labor by acting specifically via NmU-R2. Expression of NmU-R2, NmU, and NmS is detected in murine and human gestational tissues by immunoblot, and the expression of NmS in placenta and of NmU-R2 in uterus increases considerably with gestation age and labor, which is associated with amplified NmU-induced uterocontractile response in mice. NmU- and NmS-induced contraction is associated with increased NmU-R2-coupled Ca⁺⁺ transients, and Akt and Erk activation in murine primary myometrial smooth muscle cells (mSMCs), which are potentiated with gestational age. NmU-R2 is upregulated in vitro in mSMCs and in vivo in uterus in response to proinflammatory interleukin 1beta (IL1beta), which is associated with increased NmU-induced uterocontractile response and Ca⁺⁺ transients in murine and human mSMCs; additionally, placental NmS is markedly upregulated in vivo in response to IL1beta. In human placenta at term, immunohistological analysis revealed NmS expression primarily in cytotrophoblasts; furthermore, stimulation with lipopolysaccharide (LPS; Gram-negative endotoxin) markedly upregulates NmS expression in primary human cytotrophoblasts isolated from term placentas. Correspondingly, decidua of women with clinical signs of infection who delivered preterm display significantly higher expression of NmS compared with those without infection. Importantly, in vivo knockdown of NmU-R2 prevents LPS-triggered preterm birth in mice and the associated neonatal mortality. Altogether, our data suggest a critical role for NmU-R2 and its ligands NmU and NmS in preterm labor triggered by infection. We hereby identify NmU-R2 as a relevant target for preterm birth.

Prevention of preterm birth with vaginal progesterone or 17-alpha-hydroxyprogesterone caproate: a critical examination of efficacy and safety

Progestogens are the first drugs to demonstrate reproducibly a reduction in the rate of early preterm birth. The efficacy and safety of progestogens are related to individual pharmacologic properties of each drug within this class of medication and characteristics of the population that is treated. The synthetic 17-hydroxyprogesterone caproate and natural progesterone have been studied with the use of a prophylactic strategy in women with a history of preterm birth and in women with a multiple gestation. Evidence from a single large comparative efficacy trial suggests that vaginal natural progesterone is superior to 17-hydroxyprogesterone caproate as a prophylactic treatment in women with a history of mid-trimester preterm birth. Progestogen therapy is indicated for women with this highest risk profile based on evidence from 2 trials. A therapeutic approach based on the identification of a sonographic short cervix has been studied in several phase III trials. Independent phase III trials and an individual patient metaanalysis suggest that vaginal progesterone is efficacious and safe in women with a singleton and a short cervix. Two trials that tested 17-hydroxyprogesterone caproate in women with a short cervix showed no benefit. No consistent benefit for the prophylactic or therapeutic use of progestogens has been demonstrated in larger trials of women whose pregnancies were complicated by a multiple gestation (twins or triplets), preterm labor, or preterm rupture of membranes. Unfortunately, several large randomized trials in multiple gestations have identified harm related to 17-hydroxyprogesterone caproate exposure, and the synthetic drug is contraindicated in this population. The current body of evidence is evaluated by the Grading of Recommendations Assessment, Development, and Evaluation guidelines to derive the strength of recommendation in each of these populations. A large confirmatory trial that is testing 17-hydroxyprogesterone caproate exposure in women with a singleton pregnancy and a history of preterm birth is near completion. Additional study of the efficacy and safety of progestogens is suggested in well-selected populations based on the presence of biomarkers.

Exposure to the Synthetic Progestin, 17α-Hydroxyprogesterone Caproate During Development Impairs Cognitive Flexibility in Adulthood

The synthetic progestin, 17α-hydroxyprogesterone caproate, is increasingly used for the prevention of premature birth in at-risk women, despite little understanding of the potential effects on the developing brain. Rodent models suggest that many regions of the developing brain are sensitive to progestins, including the mesocortical dopamine pathway, a neural circuit important for complex cognitive behaviors later in life. Nuclear progesterone receptor is expressed during perinatal development in dopaminergic cells of the ventral tegmental area that project to the medial prefrontal cortex. Progesterone receptor is also expressed in the subplate and in pyramidal cell layers II/III of medial prefrontal cortex during periods of dopaminergic synaptogenesis. In the present study, exposure to 17α-hydroxyprogesterone caproate during development of the mesocortical dopamine pathway in rats altered dopaminergic innervation of the prelimbic prefrontal cortex and impaired cognitive flexibility with increased perseveration later in life, perhaps to a greater extent in males. These studies provide evidence for developmental neurobehavioral effects of a drug in widespread clinical use and highlight the need for a reevaluation of the benefits and potential outcomes of prophylactic progestin administration for the prevention of premature delivery.

Vaginal progesterone for maintenance tocolysis: a systematic review and metaanalysis of randomized trials

OBJECTIVE

We sought to evaluate the efficacy of maintenance tocolysis with vaginal progesterone compared to control (placebo or no treatment) in singleton gestations with arrested preterm labor (PTL) in a metaanalysis of randomized controlled trials.

STUDY DESIGN

Searches were performed in MEDLINE, OVID, Scopus, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials with the use of a combination of key words and text words related to "progesterone," "tocolysis," and "preterm labor" from 1966 through November 2014. We included all randomized trials of singleton gestations that had arrested PTL and then were randomized to maintenance tocolysis treatment with either vaginal progesterone or control (either placebo or no treatment). All published randomized studies on progesterone tocolysis were carefully reviewed. Exclusion criteria included maintenance tocolysis in women with preterm premature rupture of membrane, maintenance tocolysis with 17-alpha-hydroxyprogesterone caproate, and maintenance tocolysis with oral progesterone. The summary measures were reported as relative risks (RRs) with 95% confidence interval (CI). The primary outcome was preterm birth (PTB) <37 weeks.

RESULTS

Five randomized trials, including 441 singleton gestations, were analyzed. Women who received vaginal progesterone maintenance tocolysis for arrested PTL had a significantly lower rate of PTB <37 weeks (42% vs 58%; RR, 0.71; 95% CI, 0.57-0.90; 3 trials, 298 women). Women who received vaginal progesterone had significantly longer latency (mean difference 13.80 days; 95% CI, 3.97-23.63; 4 trials, 368 women), later gestational age at delivery (mean difference 1.29 weeks; 95% CI, 0.43-2.15; 4 trials, 368 women), lower rate of recurrent PTL (24% vs 46%; RR, 0.51; 95% CI, 0.31-0.84; 2 trials, 122 women), and lower rate of neonatal sepsis (2% vs 7%; RR, 0.34; 95% CI, 0.12-0.98; 4 trials, 368 women).

CONCLUSION

Maintenance tocolysis with vaginal progesterone is associated with prevention of PTB, significant prolongation of pregnancy, and lower neonatal sepsis. However, given the frequent lack of blinding and the generally poor quality of the trials, we do not currently suggest a change in clinical care of women with arrested PTL. We suggest instead well-designed placebo-controlled randomized trials to confirm the findings of our metaanalysis.