Prevention of preterm delivery

Placental growth factor and fetoplacental Doppler indices in combination predict preterm birth reliably in pregnancies complicated by fetal growth restriction

OBJECTIVE

To assess the association between placental biomarkers (placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio) and fetoplacental Doppler indices (umbilical artery (UA) pulsatility index (PI) and uterine artery (UtA) PI) in various combinations for predicting preterm birth (PTB) in pregnancies complicated by fetal growth restriction (FGR).

METHODS

This was a prospective observational cohort study, performed at Mater Mother's Hospital in Brisbane, Queensland, Australia, from May 2022 to June 2023, of pregnancies complicated by FGR and appropriate-for-gestational-age (AGA) pregnancies. Maternal serum PlGF levels, sFlt-1/PlGF ratio, UA-PI and UtA-PI were measured at 2-4-weekly intervals from recruitment until delivery. Harrell's concordance statistic (Harrell's C) was used to evaluate multivariable Cox proportional hazards regression models featuring various combinations of placental biomarkers and fetoplacental Doppler indices to ascertain the best combination to predict PTB (< 37 weeks). Multivariable Cox regression models were used with biomarkers as time-varying covariates.

RESULTS

The study cohort included 320 singleton pregnancies, comprising 179 (55.9%) affected by FGR, defined according to a Delphi consensus, and 141 (44.1%) with an AGA fetus. In the FGR cohort, both low PlGF levels and elevated sFlt-1/PlGF ratio were associated with significantly shorter time to PTB. Low PlGF was a better predictor of PTB than was either sFlt-1/PlGF ratio or a combination of PlGF and sFlt-1/PlGF ratio (Harrell's C, 0.81, 0.78 and 0.79, respectively). Although both Doppler indices were significantly associated with time to PTB, in combination they were better predictors of PTB than was either UA-PI > 95th centile or UtA-PI > 95th centile alone (Harrell's C, 0.82, 0.75 and 0.76, respectively). Predictive utility for PTB was best when PlGF < 100 ng/L, UA-PI > 95th centile and UtA-PI > 95th centile were combined (Harrell's C, 0.88) (hazard ratio, 32.99; 95% CI, 10.74-101.32).

CONCLUSIONS

Low maternal serum PlGF level (< 100 ng/L) and abnormal fetoplacental Doppler indices (UA-PI > 95th centile and UtA-PI > 95th centile) in combination have the greatest predictive utility for PTB in pregnancies complicated by FGR. Their assessment may help guide clinical management of these complex pregnancies. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

Maternal Nativity and Preterm Birth

Importance

Preterm birth is a major contributor to neonatal morbidity and mortality, and considerable differences exist in rates of preterm birth among maternal racial and ethnic groups. Emerging evidence suggests pregnant individuals born outside the US have fewer obstetric complications than those born in the US, but the intersection of maternal nativity with race and ethnicity for preterm birth is not well studied.

Objective

To determine if there is an association between maternal nativity and preterm birth rates among nulliparous individuals, and whether that association differs by self-reported race and ethnicity of the pregnant individual.

Design, Setting, and Participants

This was a nationwide, cross-sectional study conducted using National Center for Health Statistics birth registration records for 8 590 988 nulliparous individuals aged 15 to 44 years with singleton live births in the US from 2014 to 2019. Data were analyzed from March to May 2022.

Exposures

Maternal nativity (non-US-born compared with US-born individuals as the reference, wherein US-born was defined as born within 1 of the 50 US states or Washington, DC) in the overall sample and stratified by self-reported ethnicity and race, including non-Hispanic Asian and disaggregated Asian subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, Pacific Islander, Vietnamese, and other Asian), non-Hispanic Black, Hispanic and disaggregated Hispanic subgroups (Cuban, Mexican, Puerto Rican, and other Hispanic), and non-Hispanic White.

Main Outcomes and Measures

The primary outcome was preterm birth (<37 weeks of gestation) and the secondary outcome was very preterm birth (<32 weeks of gestation).

Results

Of 8 590 988 pregnant individuals included (mean [SD] age at delivery, 28.3 [5.8] years in non-US-born individuals and 26.2 [5.7] years in US-born individuals; 159 497 [2.3%] US-born and 552 938 [31.2%] non-US-born individuals self-identified as Asian or Pacific Islander, 1 050 367 [15.4%] US-born and 178 898 [10.1%] non-US-born individuals were non-Hispanic Black, 1 100 337 [16.1%] US-born and 711 699 [40.2%] non-US-born individuals were of Hispanic origin, and 4 512 294 [66.1%] US-born and 328 205 [18.5%] non-US-born individuals were non-Hispanic White), age-standardized rates of preterm birth were lower among non-US-born individuals compared with US-born individuals (10.2%; 95% CI, 10.2-10.3 vs 10.9%; 95% CI, 10.9-11.0) with an adjusted odds ratio (aOR) of 0.90 (95% CI, 0.89-0.90). The greatest relative difference was observed among Japanese individuals (aOR, 0.69; 95% CI, 0.60-0.79) and non-Hispanic Black individuals (aOR, 0.74; 0.73-0.76) individuals. Non-US-born Pacific Islander individuals experienced higher preterm birth rates compared with US-born Pacific Islander individuals (aOR, 1.15; 95% CI, 1.04-1.27). Puerto Rican individuals born in Puerto Rico compared with those born in US states or Washington, DC, also had higher preterm birth rates (aOR, 1.07; 95% CI, 1.03-1.12).

Conclusions and Relevance

Overall preterm birth rates were lower among non-US-born individuals compared with US-born individuals. However, there was substantial heterogeneity in preterm birth rates across maternal racial and ethnic groups, particularly among disaggregated Asian and Hispanic subgroups.

Effect of Nifedipine Used in the Treatment of the Threat of Preterm Labor on Total Uterine Artery Blood Volume Flow Rate

PURPOSE

Evaluation of the effect of maternal nifedipine treatment on total uterine artery blood volume flow rate (TVFR).

METHODS

In this prospective study, 43 women who were admitted to the Perinatology Department of the University of Health Sciences Etlik Zübeyde Hanım Gynecology Training and Research Hospital, with the diagnosis of the threat of preterm labor, and 40 healthy pregnant women, who were randomly selected as the control group, were evaluated between July 1, 2018, and September 1, 2018. A transabdominal ultrasound examination of uterine arteries was performed both before and 48 hours after administration of oral nifedipine for TVFR measurement. For the final analysis, the TVFR levels of the group diagnosed with the threat of preterm labor and the control group were compared.

RESULTS

There was no significant difference in either uterine artery pulsatility index or resistance index values as well as the diameters of the uterine arteries after nifedipine treatment (p>0.05 for all). Total uterine artery blood volume flow rate (TVFR) was 424.66±236.74 mL/min before and 543.39±309.68 mL/min after treatment with nifedipine and was statistically significantly higher (p < 0.05).

CONCLUSIONS

Our study showed a statistically significant increase in total uterine artery blood volume flow rate 48 hours after oral nifedipine treatment.

Noninvasive electromyometrial imaging of human uterine maturation during term labor

Electromyometrial imaging (EMMI) was recently developed to image the three-dimensional (3D) uterine electrical activation during contractions noninvasively and accurately in sheep. Herein we describe the development and application of a human EMMI system to image and evaluate 3D uterine electrical activation patterns at high spatial and temporal resolution during human term labor. We demonstrate the successful integration of the human EMMI system during subjects' clinical visits to generate noninvasively the uterine surface electrical potential maps, electrograms, and activation sequence through an inverse solution using up to 192 electrodes distributed around the abdomen surface. Quantitative indices, including the uterine activation curve, are developed and defined to characterize uterine surface contraction patterns. We thus show that the human EMMI system can provide detailed 3D images and quantification of uterine contractions as well as novel insights into the role of human uterine maturation during labor progression.

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'.

Effect of ritodrine hydrochloride infusion on fetal movement with the use of a fetal movement acceleration measurement recorder (FMAM recorder)

AIM

To investigate the effect of ritodrine hydrochloride infusion on fetal movement.

METHOD

We gathered 20 pregnant women who received ritodrine hydrochloride infusion as the treated group, and 147 pregnant women who did not as the control group. All women recorded gross fetal movement with the fetal movement acceleration measurement recorder after 28 gestational weeks. The record was divided into epochs of 10 s, and the ratio of movement-positive epochs to all epochs was calculated as the fetal movement index. Furthermore, the mean duration and the mean number per hour of no-fetal movement period, where the fetus did not move for 5 min or more, were calculated as the indexes of no-fetal movement. All indexes were compared between the two groups at 28-31 and 32-35 gestational weeks.

RESULTS

The fetal movement indexes (%) were 17.29 ± 7.46 (mean ± SD) in the control group and 13.65 ± 7.13 in the treated group at 28-31 weeks (p = 0.139). At 32-35 weeks, they were 14.55 ± 6.43 and 18.50 ± 5.33, respectively (p = 0.03). Similarly, the no-fetal movement indexes (min, times/h) were 15.03 ± 10.99 and 1.61 ± 0.88, and 18.70 ± 15.80 and 1.75 ± 0.96 (p = 0.824, and 0.673) at 28-31 weeks. At 32-35 weeks, they were 18.13 ± 10.88 and 1.95 ± 0.97, and 9.20 ± 5.51 and 1.14 ± 0.71, respectively (p = 0.003, and 0.003).

CONCLUSION

Ritodrine hydrochloride infusion increased the fetal movement and decreased the no-fetal movement period at 32-35 weeks.

Spontaneous preterm birth: Involvement of multiple feto-maternal tissues and organ systems, differing mechanisms, and pathways

Survivors of preterm birth struggle with multitudes of disabilities due to improper in utero programming of various tissues and organ systems contributing to adult-onset diseases at a very early stage of their lives. Therefore, the persistent rates of low birth weight (birth weight < 2,500 grams), as well as rates of neonatal and maternal morbidities and mortalities, need to be addressed. Active research throughout the years has provided us with multiple theories regarding the risk factors, initiators, biomarkers, and clinical manifestations of spontaneous preterm birth. Fetal organs, like the placenta and fetal membranes, and maternal tissues and organs, like the decidua, myometrium, and cervix, have all been shown to uniquely respond to specific exogenous or endogenous risk factors. These uniquely contribute to dynamic changes at the molecular and cellular levels to effect preterm labor pathways leading to delivery. Multiple intervention targets in these different tissues and organs have been successfully tested in preclinical trials to reduce the individual impacts on promoting preterm birth. However, these preclinical trial data have not been effectively translated into developing biomarkers of high-risk individuals for an early diagnosis of the disease. This becomes more evident when examining the current global rate of preterm birth, which remains staggeringly high despite years of research. We postulate that studying each tissue and organ in silos, as how the majority of research has been conducted in the past years, is unlikely to address the network interaction between various systems leading to a synchronized activity during either term or preterm labor and delivery. To address current limitations, this review proposes an integrated approach to studying various tissues and organs involved in the maintenance of normal pregnancy, promotion of normal parturition, and more importantly, contributions towards preterm birth. We also stress the need for biological models that allows for concomitant observation and analysis of interactions, rather than focusing on these tissues and organ in silos.

Blocking the BKCa channel induces NF-κB nuclear translocation by increasing nuclear calcium concentration

Nuclear factor kappa B (NF-κB) transcriptionally regulates several genes involved in initiating uterine contractions. A key factor controlling NF-κB activity is its translocation to the nucleus. In myometrial smooth muscle cells (MSMCs), this translocation can be stimulated by the inflammatory molecule lipopolysaccharide (LPS) or by blocking the potassium calcium-activated channel subfamily M alpha 1 (KCNMA1 or BKCa) with paxilline (PAX). Here, we sought to determine the mechanism by which blocking BKCa causes NF-κB-p65 translocation to the nucleus in MSMCs. We show that LPS- and PAX-induced NF-κB-p65 translocation are similar in that neither depend on several mitogen-activated protein kinase pathways, but both require increased intracellular calcium (Ca2+). However, the nuclear transport inhibitor wheat germ agglutinin prevented NF-κB-p65 nuclear translocation in response to LPS but not in response to PAX. Blocking BKCa located on the plasma membrane resulted in a transient NF-κB-p65 nuclear translocation that was not sufficient to induce expression of its transcriptional target, suggesting a role for intracellular BKCa. We report that BKCa also localizes to the nucleus and that blocking nuclear BKCa results in an increase in nuclear Ca2+ in MSMCs. Together, these data suggest that BKCa localized on the nuclear membrane plays a key role in regulating nuclear Ca2+ and NF-κB-p65 nuclear translocation in MSMCs.

Comparison of the Effect of Nifedipine Alone and the Combination of Nifedipine and Sildenafil in Delaying Preterm Labor: A Randomized Clinical Trial

Objective: Recently, sildenafil as a drug effective in relaxing smooth muscles can be used as an adjunct to delay the onset of uterine contractions and therefore the occurrence of preterm labor. The aim of this study was to evaluate the effect of nifedipine combination with sildenafil on preterm delivery compared with nifedipine alone. Materials and methods: This randomized double-blinded clinical trial was performed on pregnant women with a gestational age of 26-34 weeks with singleton pregnancy and symptoms of preterm delivery. The mothers were randomly assigned into two groups receiving nifedipine plus sildenafil or those receiving nifedipine alone. The time of delivery, maternal and neonatal complications were compared between the two groups. Results: Mothers who received the combination therapy experienced significantly lower preterm delivery within 72 hours of intervention compared to nifedipine alone (4.5% versus 27.3%, p = 0.002). The rate of delivery during the first 7 days after discharge was 7.6% and 31.8% in nifedipine plus sildenafil and nifedipine alone, respectively (P = 0.001). The prevalence of neonatal respiratory distress syndrome (RDS) as well as mean birth weight was higher in the nifedipine group alone. Treatment protocol with nifedipine and sildenafil compared with nifedipine alone was associated with a significant increase in preterm delivery delay (beta =-5.819, p = 0.001). Conclusion: The use of sildenafil in addition to nifedipine causes more delay in delivery in cases of preterm labor, followed by lower risk for RDS, reduces neonatal intensive care unit (NICU) admission, and preserves neonatal birth weight.

Pregnant women with more seizures have lower allopregnanolone concentrations

Neuroactive steroids have rapid, nongenomic effects on neuronal excitability. The effects in humans are less clear. We compared seizure control and concentrations of neuroactive steroids, known to influence neuroexcitability in animal studies, in pregnant women. Participants were prospectively followed throughout pregnancy with seizure-medication diaries and blood samples, assayed for steroid concentrations with gas chromatography-mass spectrometry. Baseline seizure frequency was calculated for the preconception year, and it was determined if seizure frequency was increased in each trimester. The Wilcoxon rank-sum test was used to compare neuroactive steroid concentrations in between the group with increased frequency to the group without, as calculated for the respective trimester, with the Holm-Bonferroni method to correct for multiple comparisons. Among eighty-three pregnancies included, twenty-eight had increased seizure frequency during at least one trimester (15, 18 and 10, respectively) compared to preconception seizure frequency. Allopregnanolone concentrations were lower in the 3rd trimester (p < 0.001), with a similar trend in the 1st (p = 0.08), for pregnancies with increased compared to those with stable seizure frequency. Other neuroactive steroid concentrations were similar. Our findings suggest that lower allopregnanolone concentrations are associated with increased seizure frequency during pregnancy. Validation of these finding in a larger cohort has potential important clinical applications.

Comparison the efficacy of vaginal progesterone versus 17-alpha-hydroxyprogesterone caproate to prevent preterm birth in high-risk pregnant women undergo cerclage: a randomized clinical trial

OBJECTIVE

The aim of this study was to compare the effect of vaginal progesterone with 17-alpha-hydroxyprogesterone caproate (17OHP-C) in prevention of preterm birth in high-risk pregnant women undergo cerclage.

MATERIALS AND METHODS

This prospective randomized clinical trial registered in the Iranian Registry of Clinical Trials (IRCT20181107041585N4), was performed from May 2017 to August 2018 in Bandar Abbas, Iran. Fifty-eight eligible women who were scheduled for cervical cerclage due to a history of two or more previous preterm birth <28 weeks or a cervical length less than 25 mm with at least one previous preterm birth <34 weeks were randomly divided into two groups. The first group received 200 mg of vaginal progesterone suppository daily and the second one received 250 mg of 17OHP-C intramuscular weekly after cerclage procedure until the end of 36 weeks. Patients were followed up to the end of delivery and the newborn until the first 28 d after delivery.

RESULTS

Gestational age at the time of birth in 17OHP-C group was significantly higher than vaginal progesterone group (p=.021). However, the incidence of preterm birth in both groups was not statistically significant (20.7% vs. 24.1%). Apgar scores, newborn birthweight, admission to neonatal intensive care unit (NICU), incidence of respiratory distress syndrome (RDS), sepsis, necrotizing enterocolitis (NEC), and, intraventricular hemorrhage (IVH), was similar in both groups. Adverse events were reported in 48.3% of patients in 17-OHP-C group, and 27.6% of patients in the vaginal progesterone group (p= .014).

CONCLUSIONS

Vaginal progesterone and 17OHP-C had similar results in terms of prevention of preterm birth and neonatal outcome. However, the adverse events associated with 17-OHP-C were higher than vaginal progesterone.

Novel oxytocin receptor antagonists for tocolysis: a systematic review and meta-analysis of the available data on the efficacy, safety, and tolerability of retosiban

OBJECTIVE

To assess the efficacy, safety, and tolerability of retosiban-a novel tocolytic unavailable in the US-in the management of preterm labor.

METHODS

We searched ClinicalTrials.Gov, MEDLINE, PubMed, SCOPUS, Web of Science, and the Cochrane Library for relevant clinical trials using the terms "retosiban" and "preterm labor" through 09/2020. We included all published randomized clinical trials (three) that compared retosiban to placebo for preterm labor, excluding conferences, books, reviews, posters, case reports, and animal studies. We analyzed homogeneous data under the fixed-effects model and heterogeneous data under the random-effects model.

RESULTS

We included all randomized clinical trials addressing this topic, which ultimately resulted in three trials with a total of 116 patients. There were no significant differences between retosiban and placebo in births at term (RR = 0.41, p = .02), births ≤7 days from the first study treatment (RR = 0.59, p = .23), or administration of rescue tocolytic (RR = 0.36, p = .07); the maternal adverse events of headache, anemia, constipation, or urinary tract infection (p > .05); or neonatal outcomes of Apgar score at 1 min (p = .88) or 5 min (p = .69), weight (p = .23), head circumference (p = .55), malnutrition (p = .27), hyperbilirubinemia (RR = 0.56, p = .21), jaundice (RR = 1.21, p = .84), respiratory distress (RR = 0.53, p = .49), or tachypnea (RR = 0.40, p = .42).

CONCLUSION

With the limited high quality evidence available, retosiban demonstrates no clear benefit over placebo in the management of preterm labor. Nevertheless, its favorable safety profile, oral bioavailability, and novel mechanism of action and the limited number of studies available for review warrant further analysis.

Effects of Bryophyllum pinnatum Administration on Wistar Rat Pregnancy: Biochemical and Histological Aspects

INTRODUCTION

Bryophyllum pinnatum is widely used in folk medicine. It has neuropharmacological, anti-inflammatory, immunomodulatory, antidiabetic, hepatoprotective, and nephroprotective effects, among others. It also acts on uterine contractility. It is prescribed by practitioners of anthroposophic medicine for preterm labor, insomnia, and emotional disorders, and has other potential uses in obstetrics. As all drugs currently used in preterm labor have side effects, new tocolytic agents remain an area of active research.

OBJECTIVE

To evaluate the effect of B. pinnatum mother tincture (MT) on albino rats and their offspring throughout pregnancy from a biochemical and histological standpoint.

METHODS

Longitudinal, prospective, randomized controlled bioassay. This is the second stage of a trial that investigated 60 animals distributed across six equal groups: controls C1 and C2, which received 1 and 25 times the vehicle dose (30% ethanol), B1 and B2 (1- and 25-fold doses of B. pinnatum MT), and B3 and B4 (which received 50- and 100-fold doses of B. pinnatum concentrate). At this stage, blood chemistry parameters (glucose, alanine aminotransferase [ALT], aspartate aminotransferase [AST], creatinine, and blood urea nitrogen) were measured in dams, as well as histological aspects of dam liver, kidney, placenta, and uterine tissue and fetal liver, kidney, heart, and brain.

RESULTS

No differences were found between group B1 (therapeutic dose) and its control C1 in relation to glucose, AST, ALT, and creatinine. Group B2 exhibited lower glucose levels than groups C1, B3, and B4. There was no difference in AST across groups. Groups B3 and B4 exhibited higher ALT levels than groups C1 and B1. Groups B1-B4 exhibited higher urea nitrogen levels than group C1. Creatinine levels were higher in groups B2 and B3 than group C1. On morphological evaluation, fatty infiltration of the liver was observed in the alcoholic vehicle control groups (C1 and C2).

CONCLUSIONS

Daily administration of B. pinnatum at therapeutic doses (group B1) to pregnant albino rats appears to be safe, with reduced glucose at dose B2, elevated ALT at doses B3 and B4, and increased urea at doses B1 to B4 and creatinine at B2 and B3, but never exceeding the normal reference range. It was not associated with histological changes in specimens of the maternal or fetal structures of interest.

PdCl2/DMSO-Catalyzed Thiol-Disulfide Exchange: Synthesis of Unsymmetrical Disulfide

Unsymmetrical disulfides have been effectively prepared through thiol exchange with symmetrical disulfides employing a simple PdCl₂/DMSO catalytic system. The given method features excellent functional group tolerance, a broad substrate scope, and operational simplicity. This reaction is especially useful for late-stage functionalization of bioactive scaffolds such as peptides and pharmaceuticals. Disulfide-containing organic dyes have also been prepared. This transformation could be extended to thiol-diselenide or thiol-ditelluride exchange affording RS-SeR' or RS-TeR'.

Anoctamin 1 antagonism potentiates conventional tocolytic-mediated relaxation of pregnant human uterine smooth muscle

BACKGROUND

Currently available tocolytic agents are not effective treatment for preterm labor beyond 48 h. A major reason is the development of maternal side effects which preclude the maintenance of an effective steady-state drug concentration. One strategy that can mitigate these side effects is utilizing synergistic drug combinations to reduce the drug concentrations necessary to elicit a clinical effect. We have previously shown that three anoctamin 1 (ANO1) antagonists mediate potent relaxation of precontracted human uterine smooth muscle (USM). In this study, we aimed to determine whether a combination of sub-relaxatory doses of tocolytic drugs in current clinical use [the L-type voltage-gated calcium channel (VGCC) blocker, nifedipine (NIF); and the β2-adrenergic (β2AR) agonist, terbutaline (TRB)] will potentiate USM relaxation with two ANO1 antagonists [benzbromarone (BB) and MONNA (MN)].

OBJECTIVE

This study sought to examine the synergistic potency and mechanistic basis of two ANO1 antagonists with currently available tocolytic drugs. Functional endpoints assessed included relaxation of pre-contracting pregnant human USM tissue, inhibition of intracellular calcium release, and reduction of spontaneous transient inward current (STIC) recordings in human uterine smooth muscle cells.

METHODS

Human myometrial strips and primary human USM cells were used in organ bath and calcium flux experiments with different combinations of sub-threshold doses of ANO1 antagonists and terbutaline or nifedipine to determine if ANO1 antagonists potentiate tocolytic drugs.

RESULTS

The combination of sub-threshold doses of two ANO1 antagonists and current tocolytic drugs demonstrate a significant degree of synergy to relax human pregnant USM compared to the effects achieved when these drugs are administered individually.

CONCLUSION

A combination of sub-threshold doses of VGCC blocker and β2AR agonist with ANO1 antagonists potentiates relaxation of oxytocin-induced contractility and calcium flux in human USM ex vivo. Our findings may serve as a foundation for novel tocolytic drug combinations.

Serial cervical-length measurements after first episode of threatened preterm labor improve prediction of spontaneous delivery prior to 37 weeks' gestation

OBJECTIVE

To assess whether repeat cervical-length (CL) measurement in women discharged from hospital after their first episode of threatened preterm labor can predict their risk of spontaneous preterm birth.

METHODS

This was a secondary analysis of a randomized controlled trial of maintenance tocolysis, in which CL was measured on transvaginal ultrasound at the time of hospital discharge and after 2, 4, 8 and 12 weeks, in women who remained undelivered after their first episode of threatened preterm labor. After univariate analysis, multivariate logistic regression analysis was used to assess whether CL < 10 mm at the time of hospital discharge or at any follow-up evaluation could predict spontaneous delivery prior to 37 weeks of gestation.

RESULTS

Of 226 women discharged after a diagnosis of threatened preterm labor, 57 (25.2%) delivered spontaneously prior to 37 weeks' gestation. The risk of spontaneous preterm birth was higher among women with CL < 10 mm at hospital discharge compared to those with CL ≥ 10 mm (adjusted odds ratio (aOR), 3.3; 95% CI, 1.2-9.2). Moreover, spontaneous preterm delivery was more common when CL < 10 mm was detected up to 2 weeks (aOR, 2.9; 95% CI, 1.1-7.3) or up to 4 weeks (aOR, 7.3; 95% CI, 2.3-22.8) post discharge, as compared with when CL was persistently ≥ 10 mm. The association was not significant when considering CL measurements at 8 weeks, and there was insufficient information to assess the effect of measurements obtained at 12 weeks.

CONCLUSIONS

Women who remain undelivered after their first episode of threatened preterm labor continue to be at high risk of spontaneous preterm birth if their CL is below 10 mm at the time of hospital discharge or at any follow-up visit up to 4 weeks later. CL measurement could be included in the antenatal care of these women in order to stratify their risk of preterm birth, rationalize resource utilization and help clinicians improve pregnancy outcome. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

The Associations of Genital Mycoplasmas with Female Infertility and Adverse Pregnancy Outcomes: a Systematic Review and Meta-analysis

The roles of genital mycoplasmas including Mycoplasma genitalium (M. genitalium), Mycoplasma hominis (M. hominis), Ureaplasma urealyticum (U. urealyticum), and Ureaplasma parvum (U. parvum) in reproductive diseases are equivocal. To investigate whether genital mycoplasmas are risk factors of female infertility and adverse pregnancy outcomes, we performed a systematic review and meta-analysis. Electronic databases were searched for related studies. A random-effects model or fixed-effects model was employed to generate forest plots. Pooled odd ratios (ORs) with 95% confidence intervals (CIs) were applied to measure the strength of associations. Meanwhile, heterogeneity was evaluated by H statistic and I² statistic, and publication bias was explored by funnel plots based on Egger's test and Begg's test. The search yielded 2054 relevant records, and 35 articles were ultimately included for meta-analysis. M. genitalium was a significant risk factor for female infertility (OR, 13.03 [95% CI, 3.46-48.98]) and preterm birth (PTB) (OR, 1.81 [95% CI, 1.17-2.80]), but not for spontaneous abortion (SA) (OR, 0.58 [95% CI, 0.25-1.35]). M. hominis can significantly increase the potential risk of female infertility (OR, 1.56 [95% CI, 1.02-2.38]), SA (OR, 9.14 [95% CI, 4.14-20.18]), stillbirth (OR, 3.98 [95% CI, 1.39-11.36]), and premature rupture of membranes (PROM) (OR, 1.79 [95% CI, 1.26-2.55]), but was not associated with PTB (OR, 1.29 [95% CI, 0.78-2.15]). U. urealyticum had no significant risk effect on female infertility (OR, 0.68 [95% CI, 0.42-1.11]). Coinfections of M. hominis and Ureaplasma were significantly associated with female infertility, SA, and stillbirth, but not with PROM. On the basis of current evidences, this meta-analysis supports that M. genitalium is a risk factor for female infertility and PTB; M. hominis is a potential risk factor for female infertility, SA, stillbirth, and PROM; U. urealyticum has no significant association with female infertility; and the relationship of U. parvum with female infertility and adverse pregnancy outcomes needs to be paid more attention to and remains to be further revealed.

Nanoparticles in pregnancy: the next frontier in reproductive therapeutics

BACKGROUND

Nanotechnology involves the engineering of structures on a molecular level. Nanomedicine and nano-delivery systems have been designed to deliver therapeutic agents to a target site or organ in a controlled manner, maximizing efficacy while minimizing off-target effects of the therapeutic agent administered. In both reproductive medicine and obstetrics, developing innovative therapeutics is often tempered by fears of damage to the gamete, embryo or developing foetus or of negatively impacting a woman's reproductive potential. Thus, nanomedicine delivery systems may provide alternative targeted intervention strategies, treating the source of the disease and minimizing long-term consequences for the mother and/or her foetus.

OBJECTIVE AND RATIONALE

This review summarizes the current state of nanomedicine technology in reproductive medicine and obstetrics, including safety, potential applications, future directions and the hurdles for translation.

SEARCH METHODS

A comprehensive electronic literature search of PubMed and Web of Science databases was performed to identify studies published in English up until February 2020. Relevant keywords were used to obtain information regarding use of nanoparticle technology in fertility and gene therapy, early pregnancy complications (ectopic pregnancy and gestational trophoblastic disease) and obstetric complications (preeclampsia, foetal growth restriction, preterm birth and gestational diabetes) and for selective treatment of the mother or foetus. Safety of specific nanoparticles to the gamete, embryo and foetus was also investigated.

OUTCOMES

Pre-clinical research in the development of nanoparticle therapeutic delivery is being undertaken in many fields of reproductive medicine. Non-hormonal-targeted nanoparticle therapy for fibroids and endometriosis may provide fertility-sparing medical management. Delivery of interventions via nanotechnology provides opportunities for gene manipulation and delivery in mammalian gametes. Targeting cytotoxic treatments to early pregnancy tissue provides an alternative approach to manage ectopic pregnancies and gestational trophoblastic disease. In pregnancy, nanotherapeutic delivery offers options to stably deliver silencing RNA and microRNA inhibitors to the placenta to regulate gene expression, opening doors to novel genetic treatments for preeclampsia and foetal growth restriction. Restricting delivery of teratogenic drugs to the maternal compartment (such as warfarin) may reduce risks to the foetus. Alternatively, targeted delivery of drugs to the foetus (such as those to treat foetal arrythmias) may minimize side effects for the mother.

WIDER IMPLICATIONS

We expect that further development of targeted therapies using nanoparticles in a reproductive setting has promise to eventually allow safe and directed treatments for conditions impacting the health and reproductive capacity of women and for the management of pregnancy and serious pregnancy complications.

Association between omega-3 fatty acid supplementation and lower risk of preterm delivery: a systematic review and meta-analysis

OBJECTIVE

To explore whether omega-3 fatty acid supplementation is associated with lower risk of preterm delivery.

METHODS

Searching the RCTs which were compared preterm birth between women with omega-3 fatty acid supplementation and without before December 2019 on Medline, EMBASE and Cochrane's Library, then performing a meta-analysis.

RESULTS

26 trials were identified, included 20124 women. There was almost no association between omega-3 fatty acid supplementation and lower risk of preterm delivery (risk ratio 0.92, 95% confidence interval 0.85 to 1.01, I² = 9%), gestational duration (0.30, -0.05 to 0.64, I² = 48%). In subgroup analyses, preterm delivery lower rate occurred in groups with mixed DHA and EPA supplementation not only DHA supplementation groups (P for interaction = 0.02); The dose of equivalent greater than 1 g made a higher reduction in preterm birth significantly.

CONCLUSIONS

Omega-3 fatty acid supplementation was not associated with reduced risk of preterm delivery compared with placebo or no treatment during pregnancy. Relationship between Omega-3 fatty acid supplementation and other pregnant outcomes need more evidence and clinical studies.

Neuromedin B mediates IL-6 and COX-2 expression through NF-κB/P65 and AP-1/C-JUN activation in human primary myometrial cells

Neuromedin B (NMB) and its receptor regulate labor onset by mediating inflammatory factors; however the underlying mechanisms remain poorly understood. The present study is aimed to investigate the mechanisms of NMB-induced cyclo-oxygenase 2 (COX-2) expression and interleukin (IL)-6 generation in human primary myometrial cells. The results indicated that NMB could increase phosphorylation of nuclear factor κB (NF-κB) transcription factor p65 (p65) and Jun proto-oncogene, activator protein 1 (AP-1) transcription factor subunit (c-Jun), and in turn, markedly up-regulated the expression levels of COX-2 and IL-6. This up-regulation was significantly attenuated by knockdown of p65 or c-Jun, and enhanced by overexpression of p65 or c-Jun. Furthermore, we identified a potential interaction between p65 and c-Jun following NMB stimulation. In addition, a significant positive correlation was observed between the amount of phosphorylated p65 and the levels of COX-2 and IL-6, and between the amount of phosphorylated c-Jun and COX-2 and IL-6 levels. These data suggested that NMB-induced COX-2 and IL-6 expression were mediated via p65 and c-Jun activation.

Quercetin Prevents Lipopolysaccharide-Induced Experimental Preterm Labor in Mice and Increases Offspring Survival Rate

Premature labor is still a worldwide problem, causing serious social economic burden and family burden. Currently, there is no effective way to prevent preterm labor. Since inflammation increases the risk of preterm birth and quercetin is reported to have anti-inflammation, immune-enhancement, and antioxidative effects, this study aims to explore whether quercetin exerts inhibitory effect on preterm labor in mice and increases offspring survival. Lipopolysaccharide (LPS) is one of the commonly used drugs in the inflammatory animal model of preterm birth. On day 15 of pregnancy, mice received a dose of vehicle phosphate-buffered saline (PBS) or a dose of quercetin (low concentration, 30 mg/kg; medium concentration, 90 mg/kg; high concentrations, 150 mg/kg) via oral gavage. After 2 h, mice received a dose of LPS (50 μg/kg) or vehicle intraperitoneally (i.p.). In the absence of quercetin, a 100% incidence of preterm labor was observed in LPS-treated mice, and the fetuses were all died. Medium concentration of quercetin significantly prevented 63.5% of LPS-induced inflammatory preterm labor, and the survival rate of pups on day 22 was 83.76%. Specifically, quercetin significantly inhibited LPS-induced upregulation of NF-kappa-B/P65(RELA), AP-1/C-JUN(JUN), cyclooxygenase-2(PTGS2), and interleukin 6(IL6) in mice myometrium on mRNA level and inhibited the upregulation of P65 and C-JUN on protein level. Based on these observations, we concluded that quercetin exerts inhibitory effect on LPS-induced experimental mice preterm labor and increases offspring survival through a mechanism involving NF-κB/AP-1 pathway.

Gastrointestinal and uterine smooth muscles relaxant and anti-inflammatory effects of corchorus olitorius leaf extract in laboratory animal models

ETHNO-PHARMACOLOGICAL RELEVANCE

Corchorus olitorius is reportedly used in ethno-medicine to arrest threatened miscarriage and other conditions associated with excessive uterine contractions. The plant is also used as a purgative, demulscent and an anti-inflammatory agent.

AIM OF THE STUDY

Against the background of ethno-medicinal use, this current work was designed to evaluate the gastrointestinal and uterine smooth muscles relaxant and anti-inflammatory effects of Corchorus olitorius leaf extract (COLE).

MATERIALS AND METHODS

Pieces of uterine and gastrointestinal tissues were suspended separately in organ baths containing ideal physiological salt solutions bubbled with air and were tested for responses to standard drugs and COLE, then repeated in the presence of antagonists. Anti-inflammatory study was carried out via the egg albumin-induced paw edema model in rats.

RESULTS

The application of COLE to pieces of uterine tissue significantly decreased the amplitudes of contractions in a dose dependent manner such that the highest dose applied (666.67 μg/ml) achieved a 100% inhibitory effect. Oxytocin induced contractions were also significantly inhibited by both salbutamol and COLE. On the isolated rabbit jejunum, the effect of COLE was also inhibitory and like atropine, significantly inhibited acetylcholine induced contractions. In the in vivo study, the extract inhibited charcoal meal movement in test rats when compared with control. Anti-inflammatory effect of COLE was significant and compared favourably with that of aspirin following in vivo trials.

CONCLUSIONS

COLE therefore, may be a good tocolytic, anti-diarrheal and anti-inflammatory agent and offers hope of new drug discovery for such uses.

Population Pharmacokinetics of Sulindac and Genetic Polymorphisms of FMO3 and AOX1 in Women with Preterm Labor

PURPOSE

This prospective study aimed to evaluate the effects of genetic polymorphisms in sulindac-related metabolizing enzyme genes including FMO3 and AOX1 on the population pharmacokinetics of sulindac in 58 pregnant women with preterm labor.

METHODS

Plasma samples were collected at 1.5, 4, and 10 h after first oral administration of sulindac. Plasma concentrations of sulindac and its active metabolite (sulindac sulfide) were determined, and pharmacokinetic analysis was performed with NONMEM 7.3.

RESULTS

The mean maternal and gestational ages at the time of dosing were 32.5 ± 4.4 (range, 20-41) years and 27.4 ± 4.4 (range, 16.4-33.4) weeks, respectively. In the population pharmacokinetic analysis, one depot compartment model of sulindac with absorption lag time best described the data. The metabolism of sulindac and sulindac sulfide was described using Michaelis-Menten kinetics. In stepwise modeling, gestational age impacted volume of distribution (Vc), and FMO3 rs2266782 was shown by the Michaelis constant to affect conversion of sulindac sulfide to sulindac (K_M32); these were retained in the final model.

CONCLUSIONS

Genetic polymorphisms of FMO3 and AOX1 could affect the pharmacokinetics of sulindac in women who undergo preterm labor. The results of this study could help clinicians develop individualized treatment plans for administering sulindac.

Application of N-Dodecyl l-Peptide to Enhance Serum Stability while Maintaining Inhibitory Effects on Myometrial Contractions Ex Vivo

N-Alkylation and N-acylation of the prostaglandin-F_2α allosteric modulator l-PDC31 were performed to install various alkyl, PEG and isoprenoid groups onto the l-enantiomer of the peptide. Among the different bio-conjugates studied, the N-dodecyl analog reduced prostaglandin-F_2α-induced mouse myometrium contractions ex vivo. Furthermore, N-dodecyl-l-PDC31 exhibited improved stability in a mouse serum assay, likely due to protection from protease degradation by the lipid chain.

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.

The Biomarkers for Preterm Birth Study-A prospective observational study comparing the impact of vaginal biomarkers on clinical practice when used in women with symptoms of preterm labor

INTRODUCTION

This study aims to compare the use of qualitative fetal fibronectin, quantitative fetal fibronectin, and placental α-microglobulin-1 in women with symptoms of preterm labor, to evaluate which vaginal biomarker performs the best in clinical practice.

MATERIAL AND METHODS

This prospective observational study included women who presented with symptoms of preterm labor at 24⁺⁰ to 34⁺⁰  weeks of gestation at a large tertiary maternity hospital in Auckland, New Zealand. Women were managed according to hospital guidelines using qualitative fetal fibronectin. Quantitative fetal fibronectin and placental α-microglobulin-1 tests were also taken, with clinicians blinded to the results. Management and delivery outcomes were collected from clinical records. The primary outcome was the rate of antenatal hospital admission. Analysis was performed according to predefined management protocols for each of the tests.

RESULTS

A total of 128 women had all three biomarkers tests taken. Spontaneous preterm birth rates were 7/128 (5.5%) ≤34⁺⁰  weeks and 20/128 (15.6%) <37⁺⁰  weeks of gestation; 5/128 (3.9%) delivered within 7 days of testing. Positive results were recorded in 28 qualitative fetal fibronectin tests, 25 quantitative fetal fibronectin tests with 11 ≥200 ng/mL, and 16 placental α-microglobulin-1 tests. The use of quantitative fetal fibronectin or placental α-microglobulin-1 would have lowered antenatal admission rates: 27/128 (21.1%) for qualitative fetal fibronectin, 11/128 (8.6%) for quantitative fetal fibronectin (admission threshold ≥200 ng/mL), and 15/128 (11.7%) for placental α-microglobulin-1. No additional women with quantitative fetal fibronectin <200 ng/mL delivered within 7 days or missed corticosteroids compared with standard care (qualitative fetal fibronectin); however, an additional 3 cases had a false-negative placental α-microglobulin-1 and clinical care may have been compromised (no antenatal corticosteroids or admission).

CONCLUSIONS

The use of quantitative fetal fibronectin (admission threshold ≥200 ng/mL) has the potential to reduce the rate of antenatal admissions for women with symptoms of preterm labor without compromising use of antenatal interventions that improve outcomes for babies born preterm.

Functional comparison of anoctamin 1 antagonists on human uterine smooth muscle contractility and excitability

Background: Pre-term birth is a major health care challenge throughout the world, and preterm labor represents a potentially reversible component of this problem. Current tocolytics do not improve preterm labor beyond 48 h. We have previously shown that anoctamin 1 (ANO1) channel blockade results in relaxation of pre-contracted human uterine smooth muscle (USM). Three drug classes with reported medicinal effects in humans also have members with ANO1 antagonism. In this study, we compared the ability of representatives from these 3 classes to reduce human USM contractility and excitability. Objective: This study sought to examine the comparative potency of 3 ANO1 antagonists on pregnant human USM relaxation, contraction frequency reduction, inhibition of intracellular calcium release and membrane hyperpolarization. Methods: Experiments were performed using: 1) Ex vivo organ bath (human pregnant tissue), 2) Oxytocin-induced calcium flux (in vitro human USM cells) and 3) Membrane potential assay (in vitro human USM cells). Results: Benzbromarone (BB) demonstrated the greatest potency among the compounds tested with respect to force, frequency inhibition, reducing calcium elevation and depolarizing membrane potential. Conclusion: While all 3 ANO1 antagonists attenuate pregnant human uterine tissue contractility and excitability, BB is the most potent tocolytic drug. Our findings may serve as a foundation for future structure-function analyses for novel tocolytic drug development.

Relationship Between Pregnancy Complications and Subsequent Coronary Artery Disease Assessed by Coronary Computed Tomographic Angiography in Black Women

BACKGROUND

Maternal pregnancy complications, particularly preeclampsia and gestational diabetes mellitus, are described to increase the risk for subsequent coronary artery disease (CAD). In addition, black women are at higher risk for CAD. The objective of this study was to compare the prevalence and extent of CAD as detected by coronary computed tomographic angiography (CCTA) in black women with and without a history of prior pregnancy complications.

METHODS

We retrospectively evaluated patient characteristics and CCTA findings in groups of black women with a prior history of preterm delivery (n=154), preeclampsia (n=137), or gestational diabetes mellitus (n=148), and a matched control group of black women who gave birth without such complications (n=445). Univariate and multivariate analyses were performed to assess risk factors of CAD.

RESULTS

All groups with prior pregnancy complications showed higher rates of any (≥20% luminal narrowing) and obstructive (≥50% luminal narrowing) CAD (preterm delivery: 29.2% and 9.1%; preeclampsia: 29.2% and 7.3%; and gestational diabetes mellitus: 47.3% and 15.5%) compared with control women (23.8% and 5.4%). After accounting for confounding factors at multivariate analysis, gestational diabetes mellitus remained a strong risk factor of any (odds ratio, 3.26; 95% CI, 2.03-5.22; P<0.001) and obstructive CAD (odds ratio, 3.00; 95% CI, 1.55-5.80; P<0.001) on CCTA.

CONCLUSIONS

Black women with a history of pregnancy complications, particularly gestational diabetes mellitus, have a higher prevalence of CAD on CCTA while only a history of gestational diabetes mellitus was independently associated with any and obstructive CAD on CCTA.

Activation of the epithelial sodium channel (ENaC) leads to cytokine profile shift to pro-inflammatory in labor

The shift of cytokine profile from anti‐ to pro‐inflammatory is the most recognizable sign of labor, although the underlying mechanism remains elusive. Here, we report that the epithelial sodium channel (ENaC) is upregulated and activated in the uterus at labor in mice. Mechanical activation of ENaC results in phosphorylation of CREB and upregulation of pro‐inflammatory cytokines as well as COX‐2/PGE₂ in uterine epithelial cells. ENaC expression is also upregulated in mice with RU486‐induced preterm labor as well as in women with preterm labor. Interference with ENaC attenuates mechanically stimulated uterine contractions and significantly delays the RU486‐induced preterm labor in mice. Analysis of a human transcriptome database for maternal–fetus tissue/blood collected at onset of human term and preterm births reveals significant and positive correlation of ENaC with labor‐associated pro‐inflammatory factors in labored birth groups (both term and preterm), but not in non‐labored birth groups. Taken together, the present finding reveals a pro‐inflammatory role of ENaC in labor at term and preterm, suggesting it as a potential target for the prevention and treatment of preterm labor.

Fetal lung C4BPA induces p100 processing in human placenta

The non-canonical NF-κB signaling may be a central integrator of a placental clock that governs the length of human pregnancy. We sought to identify fetal signals that could activate this NF-κB pathway in the placenta, and in turn, contribute to the onset of labor. Proteomics analysis of exosomes purified from fetal cord arterial blood revealed a total of 328 proteins, among which 48 were more significantly abundant (p < 0.01) in samples from women who delivered following elective Cesarean-section at term (39 to 40 weeks of estimated gestational age, EGA) compared to those who had elective Cesarean deliveries near term (35 to 36 weeks of EGA). Computational, crystal structural, and gene functional analyses showed that one of these 48 proteins, C4BPA, binds to CD40 of placental villous trophoblast to activate p100 processing to p52, and in turn, pro-labor genes. These results suggest that fetal C4BPA-induced activation of non-canonical NF-κB in human placenta may play a critical role in processes of term or preterm labor.

Oxytocin/vasopressin-like peptide inotocin regulates cuticular hydrocarbon synthesis and water balancing in ants

Inotocin, the oxytocin/vasopressin-like peptide, is widely conserved in arthropods; however, little is known about its molecular function. Here, we show that, in ants, the expression levels of inotocin and its receptor are correlated with the age of workers and their behavior. We also demonstrate that inotocin signaling is involved in desiccation resistance by regulating the synthesis of cuticular hydrocarbons. We propose that the up-regulation of inotocin and its receptor as workers age and switch tasks from nursing to foraging is a key physiological adaption to survive drier environments outside of the nest.

Oxytocin/vasopressin-like peptides are important regulators of physiology and social behavior in vertebrates. However, the function of inotocin, the homologous peptide in arthropods, remains largely unknown. Here, we show that the level of expression of inotocin and inotocin receptor are correlated with task allocation in the ant Camponotus fellah. Both genes are up-regulated when workers age and switch tasks from nursing to foraging. in situ hybridization revealed that inotocin receptor is specifically expressed in oenocytes, which are specialized cells synthesizing cuticular hydrocarbons which function as desiccation barriers in insects and for social recognition in ants. dsRNA injection targeting inotocin receptor, together with pharmacological treatments using three identified antagonists blocking inotocin signaling, revealed that inotocin signaling regulates the expression of cytochrome P450 4G1 (CYP4G1) and the synthesis of cuticular hydrocarbons, which play an important role in desiccation resistance once workers initiate foraging.

Is cervical length evaluated by transvaginal ultrasonography helpful in detecting true preterm labor?

Objective: To investigate whether sonographic cervical markers can identify women in true preterm labor and predict delivery within 7 d and before 34 or 37 gestational weeks.Methods: This was a prospective observational study of women with singleton pregnancies and intact membranes given a diagnosis of preterm labor between 25 and 34 weeks and 6 d of gestation and who underwent transvaginal evaluation of the following characteristics: cervical length (CL), CL zeta score, absence of endocervical glandular echo, presence of cervical funneling, and presence of amniotic fluid sludge. The outcomes of interest were spontaneous delivery within 7 d of preterm labor and spontaneous delivery before 34 or 37 gestational weeks.Results: The inclusion criteria were met by 126 women, 31 (25%) of whom were excluded and 95 were analyzed. The median gestational age at admission was 31.9 weeks. The median CL at preterm labor was 22.3 mm (range: 0-42.8 mm). The delivery occurred within 7 d of presentation in 13 (13.7%) cases. Delivery before 34 weeks occurred in 16 (16.8%) cases and before 37 weeks in 40 (42.1%) cases. Logistic regression analysis showed CL in millimeters was an independent predictor of delivery within 7 d (OR 0.918, 95% CI 0.862-0.978, p = .008). For birth before 34 weeks, the predictor was gestational age at admission (OR 0.683, 95% CI 0.539-0.866, p = .002) and before 37 weeks, the presence of cervical funneling (OR 3.778, 95% CI 1.460-9.773, p = .006). The CL ≤ 15 mm had sensitivity and specificity values of 77 and 77%, respectively, and good accuracy (88%) for prediction of delivery within 7 d.Conclusion: The evaluation of the cervix by transvaginal ultrasound in women in preterm labor predicted delivery within 7 d and helped distinguish between true and false labor. The analysis of CL zeta score was not an independent factor to predict delivery in 7 d.

Using tocolysis in pregnant women with symptomatic placenta praevia does not significantly improve prenatal, perinatal, neonatal and maternal outcomes: a systematic review and meta-analysis

BACKGROUND

Placenta praevia refers to a placenta located in the lower segment of the uterus. This abnormal location predisposes the placenta to abnormal bleeding with an increased risk of premature labour. The merits of tocolytic drugs (tocolysis) to calm uterine contractions and prolong pregnancy in women with placenta praevia are uncertain.

OBJECTIVES

The primary objective is to determine the effects of tocolysis versus no tocolysis on pregnancy prolongation. Secondary objectives include to determining the effects of tocolysis versus no tocolysis on gestational age at delivery, maternal hospitalisations, recurrent vaginal bleeding, prematurity, admissions into neonatology, and perinatal deaths.

METHODS

We searched MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials, reference lists of pertinent articles and trial registries for randomised controlled trials comparing tocolysis to no tocolysis or placebo in patients with placenta praevia. Risk of bias and data extraction was done independently by two reviewers. We pooled data using a random-effects model. We used the GRADE system to assess the certainty of evidence for each outcome.

MAIN RESULTS

There is no significant difference in pregnancy prolongation with the use of tocolysis in cases of placenta praevia (mean difference [MD] 11.51 days; 95% CI, - 1.75, 24.76; 3 trials, 253 participants; low certainty evidence). Tocolysis has no significant effect on gestational age at delivery (MD 0.33 weeks [95% CI - 1.53, 2.19]: 2 trials, 169 participants, moderate certainty evidence), birthweight (MD 0.12 kg [95% CI - 0.26, 0.5 kg]: 2 trials, 169 participants, moderate certainty evidence), risk of premature delivery (risk ratio [RR] 1.04; 95% CI 0.56, 1.94): 2 trials, 169 participants, low certainty evidence), risk of repeat vaginal bleeding (RR 1.05 [95% CI 0.73, 1.51]: 2 trials, 169 participants, moderate certainty evidence). Tocolysis has no significant effect on the risk of perinatal death (risk difference [RD]: 0.00 [95% CI - 0.04, 0.03]: 2 trials, 169 women; low certainty evidence), number of days of maternal hospitalisation (MD 0.60 days [95% CI - 0.79, 1.99]: 1 trial, 109 women; low certainty evidence), risk of fetal admissions into neonatology (RR 1.30 [95% CI 0.80, 2.12]: 1 trial, 109 participants, low certainty evidence) and on the duration of stay in neonatology units (MD 0.70 days [95% CI - 5.26, 6.66]: 1 trial, 109 participants, low certainty evidence).

CONCLUSION

In women with symptomatic placenta praevia, there is no significant effect on pregnancy prolongation with the use of tocolysis. Tocolysis has no significant effect on other prenatal, perinatal, neonatal and maternal outcomes among women with symptomatic placenta praevia.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018091513.

Oxidative Stress in Women Treated with Atosiban for Impending Preterm Birth

Preterm birth is defined as delivery before 37 completed weeks of pregnancy, and it is the leading cause of neonatal morbidity and mortality. Oxidative stress is recognized as an important factor in the pathogenesis of premature labor. We conducted this analysis to investigate the safety of administration of the tocolytic drug Atosiban—a reversible, competitive antagonist of the oxytocin receptor in the treatment of preterm birth and its impact on the level of oxidative stress in pregnant women after 48 hours of tocolytic treatment. This prospective study was conducted between March 2016 and August 2017 at the Obstetric Clinic of the Polish Mother's Memorial Hospital Research Institute. Total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) values as well as 3-nitrotyrosine, carbonyl, and thiol group levels were measured using an ELISA test in serum and plasma of 56 pregnant women before and after 48 hours of continuous administration of Atosiban. We found that TAS levels decreased almost twice after the 48-hour drug administration (0.936 ± 0.360 mmol/L vs. 0.582 ± 0.305 mmol/L, P < 0.001) while TOS increased from 18.217 ± 16.093 μmol/L to 30.442 ± 30.578 μmol/L (P < 0.001). We also found a significant increase in OSI index—almost a threefold increase from 0.022 ± 0.022 to 0.075 ± 0.085, P < 0.001. In addition, statistically significant differences in the level of carbonyl groups were found. It increased from 65.358 ± 31.332 μmol/L to 97.982 ± 38.047 μmol/L (P < 0.001), which indicates increased oxidation of plasma proteins. Furthermore, patients who gave birth prematurely had higher levels of TOS after a 48-hour drug administration than the second group with labor after 37 weeks of pregnancy (42.803 ± 34.683 μmol/L vs. 25.792 ± 27.821 μmol/L, P < 0.031). The obtained results clearly indicate that pregnant women during tocolytic treatment with Atosiban are in a state of increased oxidative stress and occurrence of preterm birth can be associated with this phenomenon. This trial is registered with NCT03570294.

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.

Evidence for CB2 receptor involvement in LPS-induced reduction of cAMP intracellular levels in uterine explants from pregnant mice: pathophysiological implications

STUDY QUESTION

What is the role of the endocannabinoid system (eCS) on the lipopolysaccharide (LPS) effects on uterine explants from 7-day pregnant mice in a murine model of endotoxin-induced miscarriage?

SUMMARY ANSWER

We found evidence for cannabinoid receptor type2 (CB2) involvement in LPS-induced increased prostaglandin-F2α (PGF2α) synthesis and diminished cyclic adenosine monophosphate (cAMP) intracellular content in uterine explants from early pregnant mice.

WHAT IS KNOWN ALREADY

Genital tract infections by Gram-negative bacteria are a common complication of human pregnancy that results in an increased risk of pregnancy loss. LPS, the main component of the Gram-negative bacterial wall, elicits a strong maternal inflammatory response that results in embryotoxicity and embryo resorption in a murine model endotoxin-induced early pregnancy loss. We have previously shown that the eCS mediates the embryotoxic effects of LPS, mainly via CB1 receptor activation.

STUDY DESIGN, SIZE, DURATION

An in vitro study of mice uterine explants was performed to investigate the eCS in mediating the effects of LPS on PGF2α production and cAMP intracellular content.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eight to 12-week-old virgin female BALB/c or CD1 (wild-type [WT] or CB1-knockout [CB1-KO]) mice were paired with 8- to 12-week-old BALB/c or CD1 (WT or CB1-KO) males, respectively. On day 7 of pregnancy, BALB/c, CD1 WT or CD1 CB1-KO mice were euthanized, the uteri were excised, implantation sites were removed and the uterine tissues were separated from decidual and embryo tissues. Uterine explants were cultured and exposed for an appropriate amount of time to different pharmacological treatments. The tissues were then collected for cAMP assay and PGF2α content determination by radioimmunoassay.

MAIN RESULTS AND THE ROLE OF CHANCE

In vitro treatment of uteri explants from 7-day pregnant BALB/c or CD1 (WT or CB1-KO) mice with LPS induced an increased production of PGF2α (P < 0.05) and a reduction of the tissue content of cAMP (P < 0.05). These effects were mediated by CB2 receptors since exposure to AM630 (a specific CB2 receptor antagonist) prevented these LPS-induced effects (P < 0.05). Collectively, our results suggest a role for the eCS mediating LPS-induced deleterious effects on reproductive tissues.

LIMITATIONS, REASONS FOR CAUTION

Since our experimental design involves in vitro experiments of uterine explants, the extrapolation of the results presented here to humans is limited.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide evidence for the role of CB2 receptors in reproductive events as well as their participation as a mediator of LPS deleterious effects on reproductive tissues.

LARGE SCALE DATA

None.

STUDY FUNDING AND COMPETING INTEREST(S)

Dr Ana María Franchi was funded by Agencia Nacional para la Promoción Científica y Tecnológica (PICT 2010/0813 and PICT 2013/0097) and by Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 2012/0061). Dr Carlos Davio was funded by Agencia Nacional para la Promoción Científica y Tecnológica (PICT 2013/2050). The authors have no competing interests.

Resveratrol protects from lipopolysaccharide-induced inflammation in the uterus and prevents experimental preterm birth

STUDY QUESTION

Is resveratrol able to prevent the lipopolysaccharide (LPS)-induced preterm labor in 15-day pregnant BALB/c mice?

SUMMARY ANSWER

Resveratrol prevented the LPS-induced onset of preterm labor in 64% of the cases and showed anti-inflammatory and tocolytic effects by downregulating COX-2 and iNOS expression and NOS activity, and by changing the uterine prostaglandin and endocannabinoid profiling.

WHAT IS KNOWN ALREADY

Genital tract infections by Gram-negative bacteria are a common complication in human pregnancy and have been shown to increase risk of preterm delivery. Bacterial LPS elicits a strong maternal inflammatory response that results in preterm delivery and fetal death in a murine model endotoxin-induced preterm labor.

STUDY DESIGN, SIZE, DURATION

An in vivo animal study was conducted. On Day 15 of pregnancy, mice received at 8:00 h a dose of vehicle (40% ethanol in saline solution) or resveratrol (3 mg/kg in vehicle) via oral gavage followed by two doses of LPS or vehicle administered intraperitoneally (i.p.), the first one at 10:00 h (0.17 mg/kg in 0.1 ml of sterile saline solution) and the second at 13:00 h (0.5 mg/kg in 0.1 ml of sterile saline solution). The mice were closely observed for any signs of morbidity (piloerection, decreased movement, and diarrhea), vaginal bleeding or preterm delivery. The beginning of preterm delivery was defined by early delivery of the first pup. Normal term labor occurs on Day 19 of gestation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Time of labor, pregnancy outcome and morphological features were evaluated after LPS and/or resveratrol administration. Uterine stripes were collected 5 h after the last LPS injection and prostaglandin and endocannabinoid profiling was analyzed by mass spectrometry. Nitric oxide synthase (NOS) activity was measured by radioconversion assay. Cyclooxygenase-2 (Cox-2) and 15-hydroxyprostaglandin dehydrogenase (15-Pgdh) mRNA levels were analyzed by RT-PCR whilst the protein expression of inducible nitric oxide synthase (iNOS), COX-1 and COX-2 were studied by western blot.

MAIN RESULTS AND THE ROLE OF CHANCE

In vivo treatment of 15-day pregnant BALB/c mice with resveratrol prevented the LPS-induced preterm birth in 64% of the cases, whereas only 15% of mice with LPS alone escaped preterm birth. Treatment with resveratrol resulted in a reduced NOS activity (P < 0.05) in the uterus of LPS-treated mice. Similarly, resveratrol reduced the expression of LPS-induced pro-inflammatory agents such as iNOS (P < 0.05), COX-2 (P < 0.05), prostaglandin E2 (PGE2) (P < 0.05) and anandamide (AEA) (P < 0.05). Moreover, resveratrol administration resulted in changes in the uterine endocannabinoid profiling altered by LPS.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Since our experimental design involves the use of mice, the extrapolation of the results presented here to humans is limited.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide evidence for the tocolytic effects of resveratrol.

STUDY FUNDING AND COMPETING INTEREST(S)

Dr Ana María Franchi was funded by Agencia Nacional para la Promoción Científica y Tecnológica (PICT 2013/0097) and by Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 2012/0061). Dr Heather B. Bradshaw was funded by NIH (DA006668). The authors have no competing interests.

Screening a small molecule library to identify inhibitors of NF-κB inducing kinase and pro-labor genes in human placenta

The non-canonical NF-κB signaling (RelB/p52) pathway drives pro-labor genes in the human placenta, including corticotropin-releasing hormone (CRH) and cyclooxygenase-2 (COX-2), making this a potential therapeutic target to delay onset of labor. Here we sought to identify small molecule compounds from a pre-existing chemical library of orally active drugs that can inhibit this NF-κB signaling, and in turn, human placental CRH and COX-2 production. We used a cell-based assay coupled with a dual-luciferase reporter system to perform an in vitro screening of a small molecule library of 1,120 compounds for inhibition of the non-canonical NF-κB pathway. Cell toxicity studies and drug efflux transport MRP1 assays were used to further characterize the lead compounds. We have found that 14 drugs have selective inhibitory activity against lymphotoxin beta complex-induced activation of RelB/p52 in HEK293T cells, several of which also inhibited expression of CRH and COX-2 in human term trophoblast. We identified sulfapyridine and propranolol with activity against CRH and COX-2 that deserve further study. These drugs could serve as the basis for development of orally active drugs to affect length of gestation, first in an animal model, and then in clinical trials to prevent preterm birth during human pregnancy.

A study of the association between the sFlt-1/PIGF ratio and preeclampsia in Xinjiang Uygur Autonomous Region of China

AIM

It was previously reported that the ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) to placental growth factor (PlGF) can predict the clinical onset of preeclampsia. This study seeks to validate the association between ratios of sFlt-1/PlGF with preeclampsia and to identify the contribution of ethnicity across diverse populations of the Xinjiang Uygur Autonomous Region.

METHODS

Pregnant women were classified into those with preeclampsia (n = 136) and healthy controls (n = 350). Serum levels of sFlt-1 and PlGF were quantified using a Roche serum instrument in both patients and controls.

RESULTS

Compared to healthy controls, women with preeclampsia had significantly higher levels of sFlt-1 (7303.81 pg/ml vs. 2508.69 pg/ml, p < .001) and ratios of sFlt-1/PlGF (241.68 vs. 14.29, p < .001), whereas levels of PIGF were decreased (241.68 vs. 14.29, p < .001). These three values varied greatly across nationalities, and non-Han Chinese subjects (including Uygur, Kazak, Hui) were more likely to experience severe preeclampsia than Han Chinese subjects.

CONCLUSIONS

This is the first study to demonstrate that the ratio of sFlt-1/PlGF can both predict and serve as a diagnostic factor for preeclampsia in pregnant women from different populations within the Xinjiang region of China.

EFFECTIVENESS AND SAFETY DIFFERENCES OF ISOXSUPRINE AND NIFEDIPINE AS TOCOLYTICS IN THE RISK OF PRETERM LABOR

Premature labor is a cause of high rates of perinatal morbidity and mortality. The use of tocolytics is one of the efforts to handle the risk of preterm labor. Tocolytics which are widely used in Indonesia is isoxsuprine and nifedipine. The purpose of this study was to identify the difference of effectiveness and safety of isoxsuprine as tocolytics in the risk of preterm labor. This was an observational study in the form of a case study that was done in detail and depth to the patients who were diagnosed as imminent preterm labor. In conclusion, there were differences in the effectiveness and safety of isoxsuprine and nifedipine as tocolytics in the risk of preterm labor.

Influence of Land or Water Exercise in Pregnancy on Outcomes: A Cross-sectional Study

PURPOSE

This study aimed to compare the cross-sectional results from three experimental studies conducted on land, in water, and in mixed form (land + water) during pregnancy on maternal and newborn outcomes.

METHODS

A cross-sectional design was used to analyze the results of three randomized clinical trials in healthy pregnant women from Madrid (Spain) and Buenos Aires (Argentina). Five hundred and sixty-eight pregnant women were recruited. For each of the studies, the number of women in the exercise group totaled 107 for study 1 (land), 49 women for study 2 (water), and 101 women for study 3 (land + water). A total of 311 women represented the control group (CG) (pooled together from all three studies).

RESULTS

Total maternal weight gain was different between study 1 and CG (11.7 vs 13.4 kg, P = 0.001, Cohen's d = 0.38) as well as the percentage of pregnant women with excessive weight gain (20.6%, n = 22, vs 37.9%, n = 118, respectively, P = 0.005, χ = 16.6, OR = 0.42, 95% confidence interval = 0.25-0.71). The number of pregnant women with gestational diabetes in CG was significantly higher than that in studies 2 and 3 (CG n = 22/7.1%; study 2, n = 0/0%; and study 3, n = 1/1%; P = 0.03, χ = 8.9).

CONCLUSION

Exercise performed on land is more effective than aquatic activities in preventing excessive maternal weight gain, whereas combined programs (land + aquatic) or water exercise programs may be more effective in preventing gestational diabetes.

Tocolysis: Present and future treatment options

In the United States, the generally accepted indication for tocolytic therapy centers on suppression of preterm labor. This may be in the form of preventative therapy with progesterone in women with prior spontaneous preterm birth or as an acute intervention to suppress established uterine contractions associated with cervical change occurring at less than 37 weeks gestation. This article seeks to apply this perspective to tocolytic therapy. Here, we provide a review of current tocolytic options and what the last decade of discovery has revealed about the regulation of myometrial excitability and quiescence. Moving forward, we must incorporate the emerging molecular data that is amassing in order to develop novel and effective tocolytic therapeutic options to prevent preterm labor and spontaneous preterm birth (sPTB).

Expression profile of C19MC microRNAs in placental tissue of patients with preterm prelabor rupture of membranes and spontaneous preterm birth

The aim of the study was to demonstrate that preterm birth (PTB) is associated with altered C19MC microRNA expression profile in placental tissues. Gene expression of 15 placental specific microRNAs (miR-512-5p, miR-515-5p, miR-516-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-519e-5p, miR-520a-5p, miR-520h, miR-524-5p, miR-525-5p, miR-526a and miR-526b-5p) was compared between groups: 34 spontaneous PTB, 108 preterm prelabor rupture of membranes (PPROM) and 20 term in labor pregnancies. Correlation between variables including relative microRNA quantification in placental tissues and the gestational age at delivery, white blood cell (WBC) count at admission and serum levels of C-reactive protein at admission in patients with PPROM and PTB was determined. Expression profile of microRNAs was different between PPROM and term in labor pregnancies, PTB and term in labor pregnancies, and between gestational age-matched PPROM and PTB groups. When compared with term in labor pregnancies, while C19MC microRNAs showed a downregulation in PPROM pregnancies (miR-525-5p), in PTB pregnancies C19MC microRNAs were upregulated (miR-515-5p, miR-516-5p, miR-518b, miR-518f-5p, miR-519a, miR-519e-5p, miR-520a-5p, miR-520h, and miR-526b-5p) or showed a trend to upregulation (miR-519d and miR-526a). In comparison to PTB pregnancies, the PPROM group demonstrated a significant portion of downregulated C19MC microRNAs (miR-516-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-519e-5p, miR-520a-5p, miR-520h, miR-525-5p, miR-526a and miR-526b-5p). In the group of PPROM pregnancies, a weak negative correlation between the gestational age at delivery and microRNA gene expression in placental tissue for all examined C19MC microRNAs was observed. PTB pregnancies showed a positive correlation (miR-512-5p, miR-515-5p, miR-519e-5p) or a trend to positive correlation (miR-516-5p, miR-518b, miR-520h) between particular C19MC microRNAs and maternal WBC count at admission. Our study demonstrates that upregulation of C19MC microRNAs is a characteristic phenomenon of PTB. PPROM pregnancies have a tendency to produce lower levels of miR-525-5p. All examined C19MC microRNAs displayed decreased expression with advancing gestational age in PPROM group.

Is nitric oxide an essential mediator in cervical inflammation and preterm birth?

OBJECTIVE

Cervical ripening is an obligatory step in the process of preterm birth. We hypothesize an inflammatory challenge to the cervix, which leads to an increase in nitric oxide production, disrupting the cervical epithelial barrier leading to preterm birth.

STUDY DESIGN

For this study, three experiments were performed: (i) Using a mouse model, pregnant mice were treated with an intrauterine injection of saline or lipopolysaccharide (LPS). Mice were sacrificed and cervices were collected for molecular analysis. (ii) Immortalized ectocervical and endocervical cells were treated with either LPS or the nitric oxide donor sodium nitroprusside (SNP). Media and RNA was collected for analysis. (iii) The integrity of the epithelial cell barrier was evaluated using an in vitro permeability assay.

RESULTS

The expression of inducible nitric oxide synthase (iNOS) was increased in our mouse model with LPS (p < .005). In vitro, LPS did not increase nitrate or nitrite concentrations or mRNA expression of iNOS. Permeability increased in the presence of LPS (p < .01), but was unchanged after treatment with SNP.

CONCLUSIONS

These studies show that LPS increases the expression of the iNOS in an animal model of preterm birth, but the nitric oxide metabolites nitrate and nitrite do not initiate the pro-inflammatory LPS-induced breakdown of the cervical epithelial barrier.

Thinking Outside the Box

A broad definition of preconditioning is "the preparation for a subsequent action." Mounting evidence demonstrates that novel remote preconditioning paradigms, in which protective stimuli experienced locally can capacitate systemic tolerance and enhanced cell viability upon exposure to ensuing cellular insults, have been largely successful in the field of cardiovascular ischemia/reperfusion injury. To ensure successful protective preconditioning, some models (including the uterus) have been demonstrated to activate the unfolded protein response (UPR), which is a cellular stress response controlled at the level of the endoplasmic reticulum. However, in the context of remote preconditioning, activation of these intracellular molecular pathways must result in the extracellular transmission of adaptive signals to remote targets. In our recently published manuscript, we have described the activation of the UPR in the pregnant uterine myocyte to be associated with increased uterine myocyte quiescence and normal gestational length. We hypothesize that ubiquitous uterine gestational stresses experienced in every pregnancy, which have been demonstrated in other systems to activate the UPR, may induce a robust paracrine dissemination of a uterine secretome, for example, glucose-regulated protein 78, with preconditioning-like properties. Furthermore, we speculate that the gestational stress-induced uterine secretome acts to promote both local and systemic tolerance to the ensuing gestational insults, allowing for the maintenance of uterine quiescence. In this context, preterm labor may be the result of a pregnant uterus experiencing a stress it cannot accommodate or when it is unable to host an appropriate UPR resulting in insufficient preconditioning and a diminished local and systemic capacity to tolerate pregnancy-dependent increases in normal gestational stress. This is highly attractive from a clinical viewpoint as we ultimately aim to identify local and systemic adaptations that may serve as preconditioning stimuli for use as a strategy to restore appropriate preconditioning profiles to prolong uterine quiescence in pregnancy.

The impact of high apparent temperature on spontaneous preterm delivery: a case-crossover study

BACKGROUND

Despite the prediction that temperatures are expected to increase in the future, little is known about the health effects of increasing temperatures on pregnant women. The objective of this study was to investigate the impact of apparent temperature on spontaneous preterm delivery (PTD).

METHODS

A case-crossover study of 14,466 singleton spontaneous preterm deliveries occurring between January 1, 1995 and December 31, 2009 among Kaiser Permanente Northern California (KPNC) members was conducted. Preterm deliveries were identified through KPNC's Electronic Health Records (EHR) data. Data on gestational age at delivery, infant sex, and maternal address were also extracted from KPNC's EHR and linked to meteorologic and air pollution monitoring data based on residential zip code.

RESULTS

An 11.6% (95% CI: 4.1, 19.7) increase in spontaneous PTD was associated with a 10 °F (5.6 °C) increase in weekly average (lag06) apparent temperature, during the warm season. During the cold season, increases in apparent temperature did not significantly impact the overall effect of spontaneous PTD (6.2%, (95% CI: -3.0, 16.2) per 10 °F (5.6 °C) increase in weekly average (lag06) apparent temperature). Significant differences in the relationship between apparent temperature and spontaneous PTD emerged for region, gestational age and infant sex, during the cold season. No significant differences emerged for air pollutants.

CONCLUSIONS

Our findings provide evidence for an increase in the odds of spontaneous PTD associated with increases in apparent temperature, especially during the warm season.