Preterm Labor and Birth Management: Recommendations from the European Association of Perinatal Medicine

Prediction and prevention of preterm birth: Quality assessment and systematic review of clinical practice guidelines using the AGREE II framework

BACKGROUND

Prediction of pregnancies at risk of preterm birth (PTB) may allow targeted prevention strategies.

OBJECTIVES

To assess quality of clinical practice guidelines (CPGs) and identify areas of agreement and contention in prediction and prevention of spontaneous PTB.

SEARCH STRATEGY

We searched for CPGs regarding PTB prediction and prevention in asymptomatic singleton pregnancies without language restriction in January 2024.

SELECTION CRITERIA

CPGs included were published between July 2017 and December 2023 and contained statements intended to direct clinical practice.

DATA COLLECTION AND ANALYSIS

CPG quality was assessed using the AGREE-II tool. Recommendations were extracted and grouped under domains of prediction and prevention, in general populations and high-risk groups.

MAIN RESULTS

We included 37 CPGs from 20 organizations; all were of moderate or high quality overall. There was consensus in prediction of PTB by identification of risk factors and cervical length screening in high-risk pregnancies and prevention of PTB by universal screening and treatment for asymptomatic bacteriuria, screening and treatment for BV in high-risk pregnancies, and use of preventative progesterone and cerclage. Areas of contention or limited consensus were the role of PTB clinics, universal cervical length measurement, biomarkers and cervical pessaries.

CONCLUSIONS

This review identified strengths and limitations of current PTB CPGs, and areas for future research.

Use and Impact of Pessary, Cerclage, and Progesterone for the Secondary Prevention of Preterm Birth: Data from the German Neonatal Network

BACKGROUND

To evaluate the use and effect of cervical stitch cerclage, pessary, and progesterone on pregnancy outcome in mothers of very low birth weight infants (VLBWI) born<32 weeks of gestation in the German Neonatal Network (GNN).

METHODS

The GNN is a population-based cohort study enrolling VLBWI since 2009. We included 575 neonates from 424 mothers into our analysis, who were born between 2015 and 2019, after prenatal intervention with cerclage, pessary, progesterone or a combination between 20/0 to 25/0 weeks of gestation to prevent preterm birth. Median intervention-to-birth interval was the primary endpoint.

RESULTS

231 of 424 pregnant women had a cerclage only (54.5%), 76 women a pessary only (17.9%), and 27 were prescribed progesterone only (15.3%). The most common combination treatment (>1 intervention group) was cerclage plus progesterone (n=27), followed by cerclage plus pessary (n=13). The median intervention-to-birth interval for the whole cohort was 24 days (IQR 19.0 days). The earlier the intervention was started, the longer the intervention-to-birth interval lasted: When started at 20 weeks, the interval was 34 days in contrast to 11.5 days, when started at 25 weeks. The >1 group was born at a significantly higher median GA with 27.0 weeks (IQR 2.9 weeks) and a higher median birth weight of 980 g (IQR 394 g) accordingly.

CONCLUSION

We propose that the earliest possible start of intervention leads to the most efficient pregnancy prolongation.

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.

Workplace Productivity Loss and Indirect Costs Associated With Preterm Birth in the United States

OBJECTIVE

To estimate workplace productivity loss and indirect costs in the year after birth among individuals who deliver preterm in the United States.

METHODS

This retrospective, observational cohort study estimated workplace productivity loss and indirect costs for individuals aged 18-55 years with an inpatient delivery between January 1, 2016, and September 30, 2021, using data from the Merative MarketScan Commercial Claims and Encounters database and the Health and Productivity Management database. Workdays lost and costs attributable to medical-related absenteeism, workplace absenteeism (defined as sick leave, leave, recreational leave, Family Medical Leave Act); disability (defined as short-term and long-term disability), and aggregate workplace productivity loss, a combined outcome measure, were compared between propensity-score-matched birth cohorts: preterm birth (before 37 weeks of gestation) and full-term birth (at or after 37 weeks of gestation). Outcomes were also compared between the full-term birth cohort and preterm birth subgroups (before 32 weeks of gestation and before 34 weeks of gestation). Estimations of indirect costs assumed an 8-hour workday. Costs were inflated to December 2021 U.S. dollars.

RESULTS

In total, 37,522 individuals were eligible for medical-related absenteeism, 1,028 for workplace absenteeism, 7,880 for disability, and 396 for aggregate workplace productivity loss after propensity score matching. Compared with full-term birth, preterm birth was associated with more workdays lost and costs in the year after childbirth attributable to medical-related absenteeism (differences of 4.2 days and $1,045, P <.001) and disability (differences of 2.8 days and $422, P <.001). Preterm birth was not associated with workplace absenteeism (differences of 1.4 days and $347, P =.787) and aggregate workplace productivity loss (differences of 5.2 days [ P =.080] and $1,021 [ P =.093]). Numerical differences were greater in magnitude and inversely related to gestational age at birth across outcomes.

CONCLUSION

Preterm birth was associated with medical-related absenteeism, disability claims, and indirect costs in the year after birth compared with full-term birth.

European guidelines on perinatal care: corticosteroids for women at risk of preterm birth

of recommendationsCorticosteroids should be administered to women at a gestational age between 24⁺⁰ and 33⁺⁶weeks, when preterm birth is anticipated in the next seven days, as these have been consistently shown to reduce neonatal mortality and morbidity. (Strong-quality evidence; strong recommendation). In selected cases, extension of this period up to 34⁺⁶weeks may be considered (Expert opinion). Optimal benefits are found in infants delivered within 7 days of corticosteroid administration. Even a single-dose administration should be given to women with imminent preterm birth, as this is likely to improve neurodevelopmental outcome (Moderate-quality evidence; conditional recommendation).Either betamethasone (12 mg administered intramuscularly twice, 24-hours apart) or dexamethasone (6 mg administered intramuscularly in four doses, 12-hours apart, or 12 mg administered intramuscularly twice, 24-hours apart), may be used (Moderate-quality evidence; Strong recommendation). Administration of two "all" doses is named a "course of corticosteroids".Administration between 22⁺⁰ and 23⁺⁶weeks should be considered when preterm birth is anticipated in the next seven days and active newborn life-support is indicated, taking into account parental wishes. Clear survival benefit has been observed in these cases, but the impact on short-term neurological and respiratory function, as well as long-term neurodevelopmental outcome is still unclear (Low/moderate-quality evidence; Weak recommendation).Administration between 34 + 0 and 34 + 6 weeks should only be offered to a few selected cases (Expert opinion). Administration between 35⁺⁰ and 36⁺⁶weeks should be restricted to prospective randomized trials. Current evidence suggests that although corticosteroids reduce the incidence of transient tachypnea of the newborn, they do not affect the incidence of respiratory distress syndrome, and they increase neonatal hypoglycemia. Long-term safety data are lacking (Moderate quality evidence; Conditional recommendation).Administration in pregnancies beyond 37⁺⁰weeks is not indicated, even for scheduled cesarean delivery, as current evidence does not suggest benefit and the long-term effects remain unknown (Low-quality evidence; Conditional recommendation).Administration should be given in twin pregnancies, with the same indication and doses as for singletons. However, existing evidence suggests that it should be reserved for pregnancies at high-risk of delivering within a 7-day interval (Low-quality evidence; Conditional recommendation). Maternal diabetes mellitus is not a contraindication to the use of antenatal corticosteroids (Moderate quality evidence; Strong recommendation).A single repeat course of corticosteroids can be considered in pregnancies at less than 34⁺⁰weeks gestation, if the previous course was completed more than seven days earlier, and there is a renewed risk of imminent delivery (Low-quality evidence; Conditional recommendation).

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/025, September 2022) - Part 2 with Recommendations on the Tertiary Prevention of Preterm Birth and on the Management of Preterm Premature Rupture of Membranes

Aim The revision of this guideline was coordinated by the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (OEGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). The aim of the guideline is to improve the prediction, prevention and management of preterm birth based on evidence from the current literature, the experience of members of the guidelines commission, and the viewpoint of self-help organizations. Methods The members of the contributing professional societies and organizations developed recommendations and statements based on international literature. The recommendations and statements were presented and adopted using a formal process (structured consensus conferences with neutral moderation, written Delphi vote). Recommendations Part 2 of this short version of the guideline presents statements and recommendations on the tertiary prevention of preterm birth and the management of preterm premature rupture of membranes.

Is mid-trimester cervical length screening effective for reduction of threatened preterm labor?

OBJECTIVE

To assess the incidence of threatened preterm labor and preterm labor admissions and treatment of women with singleton gestations and no prior preterm birth before and after implementation of the universal mid-trimester transvaginal ultrasound cervical length screening.

MATERIALS AND METHODS

A retrospective cohort study included of singleton gestations without a history of preterm birth presenting with threatened preterm labor between 24 0/7 and 36 6/7 gestational week in two study periods: before and after the implementation of the universal cervical length screening. Women with cervical length <25 mm were considered being at high risk for preterm birth and were prescribed a treatment with vaginal progesterone daily. The primary outcome was the incidence of threatened preterm labor. Secondary outcomes were the incidence of preterm labor.

RESULTS

We have found a significant increase in the incidence of threatened preterm labor from 6.42% (410/6378) in 2011 to 11.61% (483/4158) in 2018 (p < 0.0001). Gestational age at triage consult was lower in than in 2011, although the rate of admission for threatened preterm labor was similar in both periods. There was a significant decrease in the incidence of preterm delivery <37 weeks from 25.60% in 2011 to 15.94% in 2018 (p < 0.0004). Although there was a reduction in preterm delivery ≤34 weeks, this reduction was not significant.

CONCLUSION

The universal mid-trimester cervical length screening in asymptomatic women is not associated with a reduction in the frequency of threatened preterm labor or the admission rate for preterm labor, but reduces the rate of preterm births.

Quantification of cervical stiffness changes in single and twin pregnancies using the E-Cervix technique

BACKGROUND

Cervical length is a commonly used clinical indicator for evaluating preterm birth. However, some studies have shown that cervical length does not change in patients with cervical insufficiency.

OBJECTIVE

This study aimed to use the transvaginal ultrasound E-Cervix to quantitatively evaluate the cervical stiffness in women with singleton and twin pregnancies to provide a reference for the clinical prediction of preterm birth.

STUDY DESIGN

We collected the cervical length, cervical hardness ratio, mean internal os strain, and mean external os strain using transvaginal ultrasonographic E-Cervix assessments in pregnant women undergoing routine examinations in the obstetrics department of our hospital from January 2020 to December 2020. We summarized the range of cervical elasticity parameters at different gestational ages and compared the cervical elasticity parameters between singleton and twin pregnancies and between preterm births and full-term births.

RESULTS

A total of 988 pregnant women were enrolled in this study, and after exclusion, 770 pregnant women were enlisted; the interrater and internal consistency for various elasticity parameters were favorable; and cervical elasticity changes in women at full term showed some particular patterns. The declines in cervical length and hardness ratio were commensurate with gestational age, whereas the internal os strain and external os strain rose with increasing gestational age. The cervical hardness ratio in women with twin pregnancies was lower than in women with singleton pregnancies at the same gestational age, although the internal os strain in women with twin pregnancies was higher than in women with singleton pregnancies at the same gestational age (P<.05). The cervical length of women with twin pregnancies was shorter than that of women with singleton pregnancies at the same gestational age when the gestational age was ≥28 weeks of gestation (all P<.05), and the hardness ratio was linearly correlated with gestational age (r=0.68 and r=0.71). The regression model for the cervical hardness ratio in women with singleton pregnancies was hardness ratio = -0.8764×gestational age+100.99, whereas the regression model for the cervical hardness ratio in women with twin pregnancies was hardness ratio = -1.3037×gestational age+103.03. When we compared cervical elasticity parameters between preterm and full-term births, we noted that the cervical hardness ratio in pregnant women who exhibited preterm births was lower regardless of whether they carried singleton or twin pregnancies (P=.000 and P=.000), although their internal os strain was higher (P=.023 and P=.000). We observed no significant difference when we compared the cervical length and external os strain of pregnant women manifesting preterm births vs women with full-term births (P=.216 and P=.345 vs P=.475 and P=.363).

CONCLUSION

When used for the quantification of cervical hardness, the E-Cervix cervical elasticity changes in pregnant women at full term showed some particular patterns. Cervical length and hardness ratio diminished as gestational age increased, whereas internal os strain and external os strain rose as gestational age increased; moreover, the degree of these changes was greater in women with twin pregnancies than in women with singleton pregnancies. Pregnant women experiencing preterm births exhibited a reduced cervical hardness ratio and augmented internal os strain relative to women experiencing full-term births.

Ritodrine-induced rhabdomyolysis and psychiatric symptoms: a case report and literature review

BACKGROUND

Ritodrine hydrochloride, a β2-adrenergic agonist, has been widely used in Asia and Europe to treat preterm labor in pregnant women. It has some typical side effects, such as palpitations, pulmonary edema, and hypokalemia. Here, we report a case of rhabdomyolysis and psychiatric symptoms might be associated with intravenous ritodrine.

CASE PRESENTATION

A 32-year-old Chinese primigravida woman who was pregnant with twins by in vitro fertilization-embryo transfer was diagnosed with placenta previa and threatened abortion at 21 gestational weeks (GW). The patient was then treated with ritodrine hydrochloride. The initial dose of ritodrine was 150 μg/min, gradually increasing to 360 μg/min at 23^5/7 GW and 400 μg/min at 27^1/7 GW. Magnesium sulfate was added to the ritodrine regimen at 21^5/7 GW in dosage of 1-2 g/h. Psychiatric symptoms appeared at 24^5/7, 26^5/7, and 27^3/7 GW, manifesting as depression, anxiety, and suicidal tendencies. Severe muscle pain in her limbs and general weakness appeared after six weeks of ritodrine administration, which might have been a sign of rhabdomyolysis resulting from ritodrine administration. After ceasing the administration of ritodrine, the muscle pain and relevant data from laboratory tests on the patient were significantly improved, and her mood was stable. It is worth noting that this is the first time to report psychiatric symptoms may associated with the administration of ritodrine. In addition, we reviewed and analyzed six reported cases of rhabdomyolysis caused by ritodrine.

CONCLUSION

Our results suggest that we should pay more attention to the risk of rhabdomyolysis and psychiatric symptoms induced by intravenous ritodrine hydrochloride, especially in patients with a history of neuromuscular disorder, or concomitant use of magnesium sulfate.

Inflammatory Molecules Responsible for Length Shortening and Preterm Birth

It is estimated that inflammation at the placental-maternal interface is directly responsible for or contributes to the development of 50% of all premature deliveries. Chorioamnionitis, also known as the premature rupture of the amniotic membrane in the mother, is the root cause of persistent inflammation that preterm newborns experience. Beyond contributing to the onset of early labor, inflammation is a critical element in advancing several conditions in neonates, including necrotizing enterocolitis, retinopathy of prematurity, bronchopulmonary dysplasia, intraventricular hemorrhage, retinopathy of prematurity and periventricular leukomalacia. Notably, the immune systems of preterm infants are not fully developed; immune defense mechanisms and immunosuppression (tolerance) have a delicate balance that is easily upset in this patient category. As a result, premature infants are exposed to different antigens from elements such as hospital-specific microbes, artificial devices, medications, food antigens and hypoxia/hyperoxia. This has detrimental implications for preterm deliveries of less than 28 weeks because they have not yet evolved the mechanisms to tolerate maternal and self-antigens.

First Trimester Maternal Plasma Aberrant miRNA Expression Associated with Spontaneous Preterm Birth

Spontaneous Preterm Delivery (sPTD) is one of the leading causes of perinatal mortality and morbidity worldwide. The present case−control study aims to detect miRNAs differentially expressed in the first trimester maternal plasma with the view to identify predictive biomarkers for sPTD, between 320/7 and 366/7 weeks, that will allow for timely interventions for this serious pregnancy complication. Small RNA sequencing (small RNA-seq) of five samples from women with a subsequent sPTD and their matched controls revealed significant down-regulation of miR-23b-5p and miR-125a-3p in sPTD cases compared to controls, whereas miR-4732-5p was significantly overexpressed. Results were confirmed by qRT-PCR in an independent cohort of 29 sPTD cases and 29 controls. Statistical analysis demonstrated that miR-125a is a promising early predictor for sPTL (AUC: 0.895; 95% CI: 0.814-0.972; p < 0.001), independent of the confounding factors tested, providing a useful basis for the development of a novel non-invasive predictive test to assist clinicians in estimating patient-specific risk.

Testing of drugs using human feto-maternal interface organ-on-chips provide insights into pharmacokinetics and efficacy

Objectives: To improve preclinical drug testing during pregnancy, we developed multiple microfluidic organ-on-chip (OOC) devices that represent the structure, functions, and responses of the two feto-maternal interfaces (FMis) in humans (fetal membrane [FMi-OOC] and placenta [PLA-OOC]). This study utilized feto-maternal interface OOCs to test the kinetics and efficacy of drugs during pregnancy. Study design: The FMi-OOC contained amnion epithelial, mesenchymal, chorion trophoblast, and decidual cells. The PLA-OOC contained cytotrophoblasts (BeWo), syncytiotrophoblasts (BeWo + forskolin), and human umbilical vein endothelial cell lines. Therapeutic concentrations of either pravastatin or rosuvastatin (200 ng mL^-1), a model drug for these experiments, were applied to either decidua (in FMi-OOC) and syncytiotrophoblasts (in PLA-OOC) chambers under normal and oxidative stress conditions (induced by cigarette smoke extract [CSE 1 : 25]) to evaluate maternal drug exposure during normal pregnancy or oxidative stress (OS) associated pathologies, respectively. We determined statin pharmacokinetics and metabolism (LC-MS/MS), drug-induced cytotoxicity (LDH assay), and efficacy to reduce OS-induced inflammation (multiplex cytokine assay). Results: Both OOCs mimicked two distinct human feto-maternal interfaces. The drugs tested permeated the maternal-fetal cell layers of the FMi-OOC and PLA-OOC within 4 hours and generated cell and time-specific statin metabolites from various cell types without causing any cytotoxicity. OS-induced pro-inflammatory cytokines were effectively reduced by statins by increasing anti-inflammatory cytokine response across the FMi-OOC and PLA-OOC. Conclusion: Two distinct feto-maternal interface OOCs were developed, tested, and validated for their utility to conduct preclinical trials during pregnancy. We demonstrated that the placenta and fetal membranes-decidual interface both are able to transport and metabolize drugs and that the safety and efficacy of a drug can be determined using the anatomical structures recreated on OOCs.

Does a cervical pessary reduce the rate of preterm birth in women with a short cervix?

OBJECTIVES

To evaluate neonatal outcomes after the use of a cervical pessary in Japanese women with short cervical length (CL) less than 25 mm.

METHODS

This multicenter study involved women with singleton pregnancies between 20 and 29+6 gestational weeks and a CL of less than 25 mm. The primary outcome was preterm birth (PTB) before 34 weeks of gestation. This study was registered in the Japan Registry of Clinical Trials (JRCT: jRCTs042180102).

RESULTS

Two hundred pregnant women were enrolled; 114 in the pessary group and 86 in the expectant management group as controls. In the pessary group, all 114 neonates were investigated for perinatal outcomes, and 112 pregnant women were investigated for primary, and secondary outcomes. In the control group, 86 pregnant women were investigated for primary and secondary outcomes and 86 neonates were investigated for neonatal outcomes. There were no significant differences in PTB in ≤34, ≤37, and ≤28 weeks of gestation or in preterm rupture of membranes (PROM) ≤34 weeks between the groups. The gestational weeks at birth and birth weight were significantly higher in the pessary group. Regression analysis demonstrated that the CL decreased without a pessary, whereas the shortening rate was suppressed during the intervention. No significant differences were observed in adverse neonatal outcomes, chorioamnionitis, or preterm PROM.

CONCLUSIONS

The cervical pessary effectively reduced CL shortening during pregnancy resulting in an average increased gestational age, however, did not reduced the rates of preterm birth.

Timing of antenatal steroid administration for imminent preterm birth: results of a prospective observational study in Germany

PURPOSE

To evaluate the timing of antenatal steroid administration and associated medical interventions in women with imminent preterm birth.

METHODS

We performed a prospective observational study at a single tertiary center in Germany from September 2018 to August 2019. We included pregnant women who received antenatal steroids for imminent preterm birth and evaluated the interval from administration to birth. 120 women with antenatal steroid application were included into our analysis. Descriptive statistics were performed to analyze factors influencing the timing of antenatal steroids and to evaluate additional medical interventions which women with imminent preterm birth experience.

RESULTS

Of the 120 women included into our study, 35.8% gave birth before 34/0 weeks and 64.2% before 37/0 weeks of gestation. Only 25/120 women (20.8%) delivered within the optimal time window of 1-7 days after antenatal steroid application. 5/120 women (4.2%) only received one dose of antenatal steroids before birth and 3/120 (2.5%) gave birth within 8 to 14 days after antenatal steroids. Most women gave birth more than 14 days after steroid application (72.5%, 87/120). Women with preeclampsia (60%), PPROM (31%), and FGR (30%) had the highest rates of delivery within the optimal time window. Women of all timing groups received additional interventions and medications like antibiotics, tocolytics, or anticoagulation.

CONCLUSION

Our observational data indicate that most pregnant women do not give birth within 7 days after the administration of antenatal steroids. The timing was best for preterm birth due to preeclampsia, PPROM, and FGR. Especially for women with symptoms of preterm labor and bleeding placenta previa, antenatal steroids should be indicated more restrictively to improve neonatal outcome and reduce untimely and unnecessary interventions.

Colostrum Use and the Immune System of Premature Newborns: A Systematic Review and Meta-Analysis

BACKGROUND

Human colostrum has been used in a number of investigations when preterm human infants cannot, for any reason, breastfeed directly from their mothers. One of the growing fields in these investigations is colostrum therapy, which consists of exposing the oropharyngeal mucosa of these preterm newborns to small amounts of raw colostrum.

RESEARCH AIM

To critically review the scientific evidence about colostrum therapy in premature infants and to explore its influences on the immune system.

METHODS

This systematic review was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA statement). The following databases were searched for potentially eligible studies up to March 10, 2021: Medline, Scopus, Web of Science, Cochrane Library, Embase. Two reviewers independently screened all titles, abstracts, and full texts for eligibility.

RESULTS

A total of 12 studies with 996 participants were included. A significant difference in lactoferrin levels in the urine was found (SMD 0.70; 95% CI [0.03,1.36]; p = .04; I² = 65% two studies, 112 participants, very low-quality evidence).

CONCLUSION

Colostrum seems to result in increasing lactoferrin levels in the urine of premature newborns after 1 week of intervention.

CLINICAL TRIAL REGISTRATION

The study was registered at PROSPERO with the number CRD42017073624, submitted on August 9, 2017.

Risk factors associated with preterm birth after IVF/ICSI

In vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) is associated with an increased risk of preterm (33rd-37th gestational week) and early preterm birth (20th-32nd gestational week). The underlying general and procedure related risk factors are not well understood so far. 4328 infertile women undergoing IVF/ICSI were entered into this study. The study population was divided into three groups: (a) early preterm birth group (n = 66), (b) preterm birth group (n = 675) and (c) full-term birth group (n = 3653). Odds for preterm birth were calculated by stepwise multivariate logistic regression analysis. We identified seven independent risk factors for preterm birth and four independent risk factors for early preterm birth. Older (> 39) or younger (< 25) maternal age (OR: 1.504, 95% CI 1.108-2.042, P = 0.009; OR: 2.125, 95% CI 1.049-4.304, P = 0.036, respectively), multiple pregnancy (OR: 9.780, 95% CI 8.014-11.935, P < 0.001; OR: 8.588, 95% CI 4.866-15.157, P < 0.001, respectively), placenta previa (OR: 14.954, 95% CI 8.053-27.767, P < 0.001; OR: 16.479, 95% CI 4.381-61.976, P < 0.001, respectively), and embryo reduction (OR: 3.547, 95% CI 1.736-7.249, P = 0.001; OR: 7.145, 95% CI 1.990-25.663, P = 0.003, respectively) were associated with preterm birth and early preterm birth, whereas gestational hypertension (OR: 2.494, 95% CI 1.770-3.514, P < 0.001), elevated triglycerides (OR: 1.120, 95% CI 1.011-1.240, P = 0.030) and shorter activated partial thromboplastin time (OR: 0.967, 95% CI 0.949-0.985, P < 0.001) were associated only with preterm birth. In conclusion, preterm and early preterm birth risk factors in patients undergoing assisted IVF/ICSI are in general similar to those in natural pregnancy. The lack of some associations in the early preterm group was most likely due to the lower number of early preterm birth cases. Only embryo reduction represents an IVF/ICSI specific risk factor.

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.

Preterm delivery rate in China: a systematic review and meta-analysis

BACKGROUND

Preterm delivery rate is a crucial public health indicator, yet reliable statistic is currently not available in China. In this systematic review and meta-analysis, we aimed to review studies on preterm delivery rate in China, explore sources of heterogeneity, and estimate the preterm delivery rate in China.

METHODS

Published studies on preterm delivery rate in China since 2010 were electronically searched from PubMed, Embase, Web of Science, China National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang Database, and complemented by manual search. Study selection, data extraction, and quality and bias assessment (using the Joanna Briggs Institute Critical Appraisal Checklist) were conducted by two reviewers independently. Random-effects meta-analysis was performed to estimate the pooled preterm delivery rate, and prespecified stratified analysis was conducted to explore sources of heterogeneity.

RESULTS

The database search returned 4494 articles and manual search identified 10 additional studies. In total, 162 studies were eligible, of which 124 were hospital-based and 38 population-based. The pooled preterm delivery rate of hospital-based studies (7.2%; 95% CI: 6.9% to 7.6%) was significantly higher than that of population-based studies (4.9%; 95% CI: 4.5% to 5.4%) (P for subgroup difference < 0.001). Among population-based studies, the rate tended to differ by geography (P for subgroup difference = 0.07): 5.3% for Eastern, 4.6% for Central, and 3.8% for Western.

CONCLUSIONS

According to population-based studies, the preterm delivery rate in China is around 5%. This rate is substantially lower than estimates from hospital-based studies or estimates from a combination of both hospital-based and population-based studies as having been done in previous studies.

Preterm Labor: A Comprehensive Review of Guidelines on Diagnosis, Management, Prediction and Prevention

Importance

Preterm labor (PTL) is one of the most common and serious pregnancy complications associated with significant perinatal morbidity and mortality, as well as long-term neurologic impairment in the offspring.

Objective

The aim of this study was to review and compare the most recently published major guidelines on diagnosis, management, prediction, and prevention of this severe complication of pregnancy.

Evidence Acquisition

A descriptive review of guidelines from the National Institute for Health and Care Excellence (NICE), the World Health Organization, the American College of Obstetricians and Gynecologists, the New South Wales Government, and the European Association of Perinatal Medicine (EAPM) on PTL was carried out.

Results

There is a consensus among the reviewed guidelines that the diagnosis of PTL is based on clinical criteria, physical examination, measurement of cervical length (CL) with transvaginal ultrasound (TVUS) and use of biomarkers, although there is disagreement on the first-line diagnostic test. The NICE and the EAPM are in favor of TVUS CL measurement, whereas the New South Wales Government mentions that fetal fibronectin testing is the mainstay for PTL diagnosis. Moreover, there is consistency among the guidelines regarding the importance of treating PTL up to 34 weeks of gestation, to delay delivery for 48 hours, for the administration of antenatal corticosteroids, magnesium sulfate, and in utero transfer to higher care facility, although several discrepancies exist regarding the tocolytic drugs of choice and the administration of corticosteroids and magnesium sulfate after 34 and 30 gestational weeks, respectively. Routine cesarean delivery in case of PTL is unanimously not recommended. Finally, the NICE, the American College of Obstetricians and Gynecologists, and the EAPM highlight the significance of screening for PTL by TVUS CL measurement between 16 and 24 weeks of gestation and suggest the use of either vaginal progesterone or cervical cerclage for the prevention of PTL, based on specific indications. Cervical pessary is not recommended as a preventive measure.

Conclusions

Preterm labor is a significant contributor of perinatal morbidity and mortality with a substantial impact on health care systems. Thus, it seems of paramount importance to develop consistent international practice protocols for timely diagnosis and effective management of this major obstetric complication and subsequently improve pregnancy outcomes.

Inflammation and Preterm Birth: A Systematic Review

Inflammatory mechanisms have a critical role in parturition, which results from a gathering of different stimuli that collectively initiate labour. In fact, a sophisticated interaction occurs between contractile and immuno-inflammatory pathways, whereby proinflammatory amplification is intensified by collaborative connections between cells, ligands, and tissues. Preterm birth (PTB) is one of the major challenges of modern obstetrics and still lacks an efficient treatment. Therefore, the scientific research of modern therapies is warranted. This systematic review aims to provide an overview of recent research into inflammation and PTB. The main inclusion criterion was articles concerning birth and inflammation, and searches were performed in the electronic databases MEDLINE, Embase, Scopus, Web of Science and Cochrane Library, from 2017 to 2021. A literature search from all databases yielded 1989 results which, applying the specified eligibility criteria, resulted in the 16 articles included in this review. Delivery is the consequence of an inequity between maternal inflammation and hormonal-driven uterine quiescence. Studies show that the distinction between term and preterm labour could consist of a pre-existing disproportion of decidual inflammatory signalling, or an unusual stimulus eliciting inflammatory pathways, comparable to both. Thus, controlling inflammation could be hopeful for detaining PTB.

Progesterone, cervical cerclage or cervical pessary to prevent preterm birth: a decision-making analysis of international guidelines

Objective

The aim of this study was to investigate guidelines on preterm birth, analyze decision-criteria, and to identify consensus and discrepancies among these guidelines.

Design

Objective consensus analysis of guidelines.

Sample

Ten international guidelines on preterm birth.

Methods

Relevant decision criteria were singleton vs. twin pregnancy, history, cervical length, and cervical surgery / trauma or Mullerian anomaly. Eight treatment recommendations were extracted. For each decision-making criteria the most commonly recommended treatment was identified, and the level of consensus was evaluated.

Main outcome measures

Consensus and Discrepancies among recommendations.

Results

In a case of singleton pregnancies with no history of preterm birth and shortened cervix, most guidelines recommend progesterone. In singleton pregnancies with a positive history and shortened cervix, all guidelines recommend a cerclage as an option, alternative or conjunct to progesterone. The majority of the guidelines advise against treatment in twin pregnancies.

Conclusions

A shortened cervix and a history of preterm birth are relevant in singleton pregnancies. In twins, most guidelines recommend no active treatment.

Tweetable abstract

Among international guidelines a shortened cervix and a history of preterm birth are relevant in singleton pregnancies. With no history of preterm birth and with a shortened cervix most guidelines recommend progesterone treatment.

A Growing Dilemma: Antenatal Corticosteroids and Long-Term Consequences

OBJECTIVE

A single course of synthetic antenatal corticosteroids is standard care for women considered to be at risk for preterm birth before 34 weeks of gestation. While the intended target is the fetal lung, the fetal brain contains remarkably high levels of glucocorticoid receptors in structures critical in the regulation of behavior and endocrine function. Negative programming signals may occur which can lead to permanent maladaptive changes and predispose the infant/child to an increased risk in physical, mental, and developmental disorders.

METHODS

Framed around these areas of concerns for physical, mental, and developmental disorders, this narrative review drew on studies (animal and clinical), evaluating the long-term effects of antenatal corticosteroids to present the case that a more targeted approach to the use of antenatal corticosteroids for the betterment of the fetus urgently needed.

RESULTS

Studies raised concerns about the potential negative long-term consequences, especially for the exposed fetus who was born beyond the period of the greatest benefit from antenatal corticosteroids. The long-term consequences are more subtle in nature and usually manifest later in life, often beyond the scope of most clinical trials.

CONCLUSION

Continued research is needed to identify sufficient safety data, both short term and long term. Caution in the use of antenatal corticosteroids should be exercised while additional work is undertaken to optimize dosing strategies and better identify women at risk of preterm birth prior to administration of antenatal corticosteroids.

KEY POINTS

· A single-course ACS is a remarkable therapy with substantial benefits.. · There is a potential of long-term neurodevelopmental consequences in the ACS-exposed fetus.. · There is a need to improve dosing strategies and identification of appropriate at risk women..

Effects of maternal ritodrine hydrochloride administration on the heart rate of preterm fetal sheep with intraamniotic inflammation

Ritodrine hydrochloride is used for pregnancy prolongation and intrauterine fetal resuscitation. However, its clinical significance in intraamniotic inflammation during preterm labor and intrauterine fetal distress is unclear. We investigated the effects of maternal ritodrine hydrochloride administration (MRA; 200 μg/min for 2 h, followed by 800 μg/min for 2 h after 24 h) on fetal physiological parameters. For this purpose, we used chronically instrumented pregnant sheep at 113–119 d (term = 145 d) of gestation without (Group 1, n = 5) and with (Group 2, n = 5) intraamniotic inflammation induced by lipopolysaccharide injection into the amniotic cavity. The changes in fetal heart rate (FHR) and short-term variability (STV) and long-term variability (LTV) in FHR, fetal blood pressure, and fetal arterial blood gas (FABG) values were measured before and at 1 and 2 h after initiating MRA. Before MRA, all parameters were similar between Groups 1 and 2; however, there was significantly higher STV in Group 2 than in Group 1 before MRA at 800 μg/min, significantly higher partial arterial pressure of carbon dioxide in FABG in Group 2 than in Group 1 before MRA at 200 μg/min, and significantly lower blood glucose (BG) in Group 2 than in Group 1 before MRA at 800 μg/min. One hour after MRA, the FHR, STV, and LTV were significantly higher at 800 μg/min than those at the baseline in Group 1, as determined by the Friedman test; however, no significant difference was observed in Group 2. Additionally, the FABG pH significantly decreased 1 h after MRA at 800 μg/min in Group 2, whereas FABG lactate and BG significantly increased 2 h after MRA at 800 μg/min in Groups 1 and 2. Thus, short-term MRA at 800 μg/min increased the FHR, STV, and LTV significantly; these values were further modified under intraamniotic inflammation.

Patient’s experience with the Arabin cervical pessary during pregnancy: A questionnaire survey

Introduction

The cervical pessary is used in women with precocious cervical ripening to prevent preterm birth. Up to now however, there have been no systematic studies on compliance and tolerance, which vary among different study cohorts.

Material and methods

A questionnaire was administered to 166 women treated with the Arabin cervical pessary in one center. Data were analysed about the patient’s experience before insertion (adequacy of information received), during treatment (follow-up, impact on daily life, perceived discomfort, side effects) and at the time of removal (pain, if the patient’s expectations had been met regarding the treatment).

Results

Information received before the insertion of the Arabin cervical pessary was considered adequate in 163/166 (98.2%) women. An increase in vaginal discharge was experienced by 70/166 (42.2%) women. Discomfort or other side effects were reported in 13.8% and 16.3% of cases, respectively. Overall, 77% of women reported an improved quality of life and 94% considered the follow-up during pregnancy adequate. Removal was moderately painful for 58/166 (35%) of women. Patient’s expectations regarding the treatment were exceeded in the majority of cases (75.3%). In a final step, we compared our results to previous studies regarding the use of the pessary in singleton and twin pregnancies.

Conclusion

Although some trials report high rates of non-compliant patients, this could not be confirmed by our study. In contrast, most women reported having a positive experience and that they were motivated to continue the treatment when they were continuously followed by experienced clinicians.

A Timely Administration of Antenatal Steroids Is Highly Protective Against Intraventricular Hemorrhage: An Observational Multicenter Cohort Study of Very Low Birth Weight Infants

AIM

The aim of the study is to evaluate the influence of the timing of antenatal steroids (ANSs) on neonatal outcome of very low birth weight infants (VLBWI) born before 30 weeks of gestation in the German Neonatal Network.

METHODS

The German Neonatal Network is a large population-based cohort study enrolling VLBWIs since 2009. We included 672 neonates, who were born between January 1, 2009 and December 31, 2019 in our analysis in 10 selected centers. Infants were divided into four subgroups based on the interval between the first steroid administration and preterm birth: (I) two doses of betamethasone, ANS-birth interval: >24 h to 7 days, n = 187, (II) only one dose of betamethasone, ANS-birth interval 0-24 h, n = 70, (III) two doses of betamethasone, ANS-birth interval >7 days, n = 177, and (IV) no antenatal steroids, n = 238. Descriptive statistics and logistic regression analyses were performed for the main neonatal outcome parameters. Group IV (no ANS) was used as a reference.

RESULTS

An ANS-birth interval of 24 h to 7 days after the first dose was associated with a reduced risk for intraventricular hemorrhage (OR 0.17; 95% CI 0.09-0.31, p < 0.001) and mechanical ventilation (OR 0.37; 95% CI 0.23-0.61, p < 0.001), whereas the group of infants that only received a single dose of steroids reflected a subgroup at high risk for adverse neonatal outcomes; an ANS-birth interval of >7 days was still associated with a lower risk for intraventricular hemorrhage (OR 0.43; 95% CI 0.25-0.72, p = 0.002) and the need for mechanical ventilation (OR 0.43; 95% CI 0.27-0.71, p = 0.001).

CONCLUSION

Our observational data indicate that an ANS-birth interval of 24 h to 7 days is strongly associated with a reduced risk of intraventricular hemorrhage in VLBWIs. Further research is needed to improve the prediction of preterm birth in order to achieve a timely administration of antenatal steroids that may improve neonatal outcomes such as intraventricular hemorrhage.

IL-27 Mediates Pro-Inflammatory Effects via the ERK Signaling Pathway During Preterm Labor

Preterm labor (PTL) is a multifactorial syndrome that results in birth prior to 37 weeks of gestation. However, the specific molecular mechanisms underlying this condition have yet to be elucidated. Previous research demonstrated that the abnormal expression of IL-27, and its receptors, played a role in the pathophysiology of preterm labor. In the present study, we established a Lipopolysaccharide (LPS)-stimulated, infection-induced, preterm mouse model based on wild-type C57BL/6 mice and WSX-1^-/-C57BL/6 mice. WSX-1 knockdown led to a significant delay in birth by 11.32 ± 2.157h. In addition, compared with wild-type C57B/6 mice, the expression levels of IFN-γ, IL-1β, IL-6, TNF-α, and CXCL10, in the fetal membrane and myometrium of WSX-1^-/-mice were significantly lower, particularly in the myometrium. We also confirmed similar pro-inflammatory effects arising from IL-27 in human amniotic cell line (WISH) and human myometrial smooth muscle cell line (HMSMC). Once stimulated by LPS, the pro-inflammatory action exhibited a synergistic effect and appeared to be time-dependent. Finally, we demonstrated that LY3214996, an inhibitor of the ERK pathway, significantly inhibited the pro-inflammatory effect mediated by IL-27. Overall, our data confirmed that the inflammatory effect mediated by the IL-27/IFN-r/ERK axis is involved in preterm labor. Our findings, therefore, provide an enhancement in our etiological understanding of the mechanisms underlying PTL.

Prevention of Preterm Birth with Progesterone

Gestational age at birth is a critical factor for perinatal and adulthood outcomes, and even for transgenerational conditions' effects. Preterm birth (PTB) (prematurity) is still the main determinant for infant mortality and morbidity leading cause of infant morbidity and mortality. Unfortunately, preterm birth (PTB) is a relevant public health issue worldwide and the global PTB rate is around 11%. The premature activation of labor is underlined by complex mechanisms, with a multifactorial origin influenced by numerous known and probably unknown triggers. The possible mechanisms involved in a too early labor activation have been partially explained, and involve chemokines, receptors, and imbalanced inflammatory paths. Strategies for the early detection and prevention of this obstetric condition were proposed in clinical settings with interesting results. Progesterone has been demonstrated to have a key role in PTB prevention, showing several positive effects, such as lower prostaglandin synthesis, the inhibition of cervical stromal degradation, modulating the inflammatory response, reducing gap junction formation, and decreasing myometrial activation. The available scientific knowledge, data and recommendations address multiple current areas of debate regarding the use of progesterone in multifetal gestation, including different formulations, doses and routes of administration and its safety profile in pregnancy.

Cumulative life stressors and stress response to threatened preterm labour as birth date predictors

PURPOSE

Preterm birth represents one of the main causes of neonatal morbimortality and a risk factor for neurodevelopmental disorders. Appropriate predictive methods for preterm birth outcome, which consequently would facilitate prevention programs, are needed. We aim to predict birth date in women with a threatened preterm labour (TPL) based on stress response to TPL diagnosis, cumulative life stressors, and relevant obstetric variables.

METHODS

A prospective cohort of 157 pregnant women with TPL diagnosis between 24 and 31 weeks gestation formed the study sample. To estimate the stress response to TPL, maternal salivary cortisol, α-amylase levels, along with anxiety and depression symptoms were measured. To determine cumulative life stressors, previous traumas, social support, and family functioning were registered. Then, linear regression models were used to examine the effect of potential predictors of birth date.

RESULTS

Lower family adaptation, higher Body Mass Index (BMI), higher cortisol levels and TPL diagnosis week were the main predictors of birth date. Gestational week at TPL diagnosis showed a non-linear interaction with cortisol levels: TPL women with middle- and high-cortisol levels before 29 weeks of gestation went into imminent labour.

CONCLUSION

A combination of stress response to TPL diagnosis (salivary cortisol) and cumulative life stressors (family adaptation) together with obstetric factors (TPL gestational week and BMI) was the best birth date predictor. Therefore, a psychosocial therapeutic intervention program aimed to increase family adaptation and decrease cortisol levels at TPL diagnosis as well as losing weight, may prevent preterm birth in symptomatic women.

Self-reported pain scores as a predictor of preterm birth in symptomatic twin pregnancy: a retrospective study

BACKGROUND

To evaluate the self-reported pain scores as a predictor of preterm birth (PTB) in symptomatic twin pregnancy and to develop a nomogram for the prediction model.

METHODS

We conducted a retrospective study of 148 cases of symptomatic twin pregnancies before 34 weeks of gestation visited at Seoul national university hospital from 2013 to 2018. With other clinical factors, self-reported pain score was evaluated by the numerical rating scale (NRS) pain scores for pain intensity. By multivariate analyses and logistic regression, we developed a prediction model for PTB within 7 days. Using the Cox proportional hazards model, the curves were plotted to show the predictability of the PTB according to NRS pain score, while adjusting the other covariates.

RESULTS

Twenty-three patients (15.5 %) delivered preterm within 7 days. By a logistic regression analysis, higher NRS pain score (OR 1.558, 95 % CI 1.093-2.221, P < 0.05), shorter cervical length (OR 3.164, 95 % CI 1.262-7.936, P < 0.05) and positive fibronectin results (OR 8.799, 95 % CI 1.101-70.330, P < 0.05) affect PTB within 7 days. Using the variables, the area under the receiver operating characteristic curve (AUROC) of the prediction model was 0.917. In addition, we developed a nomogram for the prediction of PTB within 7 days.

CONCLUSIONS

Self-reported pain scores combined with cervical length and fetal fibronectin are useful in predicting impending PTB in symptomatic twin pregnancy.

Cervical pessary plus vaginal progesterone in a singleton pregnancy with a short cervix: an experience-based analysis of cervical pessary's efficacy

BACKGROUND

Several studies were published about cervical pessary, with controversial results. These studies demonstrated that the patient follow-up after pessary insertion is very different between the study centers and the number of pessary insertions per center was often <30 cases. This study aims to determine cervical pessary performance in singleton pregnancies with a short cervix based on a single center learning curve.

METHODS

Between 2011 and 2018, 128 singleton pregnancies between 18 and 24 gestational weeks with a short cervix (<25 mm) were referred to our clinic. All cases were treated with progesterone, and when available in our supplies (due to low resources) cervical pessary was also offered. Three groups were created for statistical analysis: Group 1 (n = 33), treated with progesterone-only; Groups 2 and 3, treated with cervical pessary plus progesterone. Group 2 included the first cases (n = 30) of pessary, defined by a learning curve and cumulative sum analysis, while Group 3 included the subsequent 65 cases. The primary outcome was preterm birth (PTB) < 34 gestational weeks.

RESULTS

The learning curve was performed with all cases of pessary plus progesterone, and 30 patients were obtained as the number needed for learning, in our study with two operators. The PTB rate < 34 weeks was 27.3, 20, and 4.6% in groups 1, 2, and 3, respectively. There was no significant difference between Group 1 and 2 (OR 1.1; 95% CI 0.066 - 18.45; p = .945). When comparing Groups 1 and 3 there was a significant difference in PTB rates (OR 0.08; CI95% 0.01-0.42; p = .003). Considering Kaplan-Meyer Survival analysis, we can observe that the performance of progesterone alone (Group 1) was similar to Group 2 (progesterone + first 30 cases of pessary) (p = .432), but the performance of Group 3 (progesterone + subsequent 65 cases of pessary) and Group 1 shows a statistically significant difference (p = .011).

CONCLUSION

Learning curve and cumulative sum analysis determined that the application and surveillance of at least 30 patients is required to see significant improvements in the primary outcome of PTB < 34 weeks.

A Question of Timing: 10-year Retrospective Analysis on the Use of Antenatal Steroids for Imminent Preterm Birth

OBJECTIVE

Antenatal steroids improve the neonatal outcome if they are administered within a therapeutic window of seven days before preterm birth. The aim of this study was to evaluate the timing of antenatal steroids for imminent preterm birth at a single center in Germany.

MATERIAL AND METHODS

A 10-year retrospective analysis of 843 preterm births between 24/0 and 33/6 weeks was performed from January 2008 to December 2017 at a German university hospital. We evaluated the timing of antenatal steroids according to the indication for their application. Descriptive statistics and binomial regression were performed to analyze factors influencing the timing of antenatal steroid administration.

RESULTS

Of 843 preterm births below 34 weeks included in our study, 752 pregnant women received antenatal steroids (89.2%). Only 301/843 women (35.7%) gave birth within the optimal window of 7 days after antenatal steroids. 91/843 women (10.8%) did not receive steroids. 130/843 women (15.4%) only received one dose, 76/843 (9.0%) gave birth within 8 to 14 days, and 245/843 (29.1%) more than 14 days later. In a binomial regression model, preterm premature rupture of membranes (OR 3.40, 95% CI 1.81 to 6.39, p<0.001), fetal growth restriction (OR 3.27, 95% CI 1.63 to 6.58, p=0.001), and preeclampsia (OR 2.83, 95% CI 1.37 to 5.83, p=0.005) were positively associated with optimal timing.

CONCLUSION

Two thirds of women with preterm birth before 34 weeks received antenatal steroids outside the optimal therapeutic window. Further research is needed to achieve an optimal effect of antenatal steroids on neonatal outcome and to reduce untimely as well as unnecessary interventions.

Neonatal outcome after conservative-reconstructive surgery for placenta accreta spectrum disorders

AIM

To report the neonatal outcome after conservative-reconstructive surgery for placenta accreta spectrum (PAS) disorders.

MATERIALS AND METHODS

Inclusion criteria were women undergoing conservative-reconstructive surgery for PAS. The outcomes explored were: 5 min Apgar score, birth weight, and need for ventilatory support (RS1 supplementary oxygen, RS2 nasal positive pressure ventilation, or RS3 mechanical ventilatory assistance). Descriptive statistics (means and standard deviations for quantitative and percentage and interquartile range for quantitative variables) were sued to report the data.

RESULTS

84% of women with PAS type 1 were delivered between 35 and 37 weeks of gestation. There was only one case of small for gestational age (SGA) newborn 81% of the newborns required admission to the NICU and 11% respiratory support of those pregnancies complicated by PAS type 2, 59% were delivered between 35 and 36.6 weeks. Neonatal birth weight was consistent with gestational age at birth for all the included cases, and there was no SGA newborn in this group. 84% of the newborns required admission to the NICU, while 21% respiratory support. All women with PAS type 3 were delivered between 30 and 33 weeks of gestation. Although all newborns were admitted to NICU and 73% required ventilatory support, there was no SGA case. Pregnancies complicated by PAS type 4 completed their pregnancy between weeks 35 and 37. There was no case affected by SGA; although all newborns were admitted to NICU, none required ventilatory support.

CONCLUSIONS

Conservative surgery in pregnancies complicated by PAS does not seem to increase the risk of adverse neonatal outcomes. Early gestational age at birth and invasion in the inferior third of the lower uterine segment is associated with an increased incidence of neonatal complications, likely due to the earlier gestational age at delivery for these pregnancies.

Role of cervical length and placental alpha microglobulin-1 to predict preterm birth

INTRODUCTION

Preterm labor is the leading cause of premature mortality and morbidity. Therefore, to rule-in and rule-out preterm delivery is a very important issue in our clinical practice.

OBJECTIVE

The aim of this study was to investigate the value of placental alpha microglobulin-1 (PAMG-1) molecule positivity in cervicovaginal secretions of women who have a CL <25 mm and presenting with preterm labor symptoms to predict spontaneous preterm birth within seven days.

MATERIALS AND METHODS

This was a prospective cohort study conducted in Ankara University Department of Obstetrics and Gynecology between August 2017 and February 2019 on the patients who had Preterm labor symptoms, <25 mm transvaginal cervical length (CL), clinically intact membranes. The primary outcome of the study was the power of CL and PAMG-1 positivity on the prediction of preterm birth in seven days.

RESULTS

Sensitivity and specificity values of PAMG-1 in our study population to predict spontaneous preterm birth in seven days were calculated 52.94% and 98.84%, respectively, negative predictive value (NPV) and positive predictive value (PPV) were calculated 91.4% and 90%, respectively. When we investigated our data according to different CL cutoffs, sensitivity and NPV for 20 mm cutoff were 88.24% and 96.3% that was better than PAMG-1, but specificity and PPV were 60.47% and 30.61%, respectively, that was more ineffective than PAMG-1. If we calculate the values according to 15 mm and 10 mm CL cutoffs sensitivity values were 58.8% and 23.53%, specificity values were 81.4% and 91.86%, NPV were 90.9% and 85.87%, PPV were 38.46% and 36.36%, respectively. Finally, accuracy value of PAMG-1 to predict spontaneous preterm birth in seven days was 91.26% that was better than other CL cutoffs (20 mm, 15 mm, and 10 mm).

CONCLUSION

PAMG-1 molecule with high NPV and PPV (91.4% and 90%) combination will contribute our clinical decision on the population who had preterm labor symptoms and a CL shorter than 25 mm.

Guidelines on Deferred Cord Clamping and Cord Milking: A Systematic Review

CONTEXT

Deferred cord clamping (DCC) saves lives. It reduces extremely preterm infants' mortality by 30%, yet a minority of eligible infants receive it. This may in part be due to lack of awareness or confidence in evidence, or conflicting or vague guidelines.

OBJECTIVE

To systematically review clinical practice guidelines and other statements on DCC and cord milking.

DATA SOURCES

Ten academic and guideline databases were searched.

STUDY SELECTION

Clinical practice guidelines and other statements (position statements and consensus statements) providing at least 1 recommendation on DCC or umbilical cord milking among preterm or term infants were included.

DATA EXTRACTION

Data from included statements were extracted by 2 independent reviewers, and discrepancies were resolved through consensus. Guideline quality was appraised with modified Appraisal of Guidelines for Research and Evaluation II and Appraisal of Guidelines for Research and Evaluation Recommendation Excellence tools.

RESULTS

Forty-four statements from 35 organizations were included. All endorsed DCC for uncompromised preterm infants, and 11 cautiously stated that cord milking may be considered when DCC is infeasible. Only half (49%) of the recommendations on the optimal duration of DCC were supported by high-quality evidence. Only 8% of statements cited a mortality benefit of DCC for preterm infants.

LIMITATIONS

Because systematic reviews of guidelines are relatively novel, there are few tools to inform study execution; however, we used the Appraisal of Guidelines for Research and Evaluation II and the Appraisal of Guidelines for Research and Evaluation Recommendation Excellence to assess quality and were methodologically informed by previous systematic reviews of guidelines.

CONCLUSIONS

Statements worldwide clearly encouraged DCC. Their implementability would benefit from noting the preterm mortality benefit of DCC and more granularity.

Cervical Pessary Plus Progesterone for Twin Pregnancy with Short Cervix Compared to Unselected and Non-Treated Twin Pregnancy: A Historical Equivalence Cohort Study (EPM Twin Pessary Study)

OBJECTIVE

 The present study aims to determine if the use of cervical pessary plus progesterone in short-cervix (≤ 25 mm) dichorionic-diamniotic (DC-DA) twin pregnancies is equivalent to the rate of preterm births (PBs) with no intervention in unselected DC-DA twin pregnancies.

METHODS

 A historical cohort study was performed between 2010 and 2018, including a total of 57 pregnant women with DC-DA twin pregnancies. The women admitted from 2010 to 2012 (n = 32) received no treatment, and were not selected by cervical length (Non-Treated group, NTG), whereas those admitted from 2013 to 2018 (n = 25), were routinely submitted to cervical pessary plus progesterone after the diagnosis of short cervix from the 18th to the 27th weeks of gestation (Pessary-Progesterone group, PPG). The primary outcome analyzed was the rate of PBs before 34 weeks.

RESULTS

 There were no statistical differences between the NTG and the PPG regarding PB < 34 weeks (18.8% versus 40.0% respectively; p = 0.07) and the mean birthweight of the smallest twin (2,037 ± 425 g versus 2,195 ± 665 g; p = 0.327). The Kaplan-Meyer Survival analysis was performed, and there were no differences between the groups before 31.5 weeks. Logistic regression showed that a previous PB (< 37 weeks) presented an odds ratio (OR) of 15.951 (95% confidence interval [95%CI]: 1.294-196.557; p = 0.031*) for PB < 34 weeks in the PPG.

CONCLUSION

 In DC-DA twin pregnancies with a short cervix, (which means a higher risk of PB), the treatment with cervical pessary plus progesterone could be considered equivalent in several aspects related to PB in the NTG, despite the big difference between these groups.

Regarding the evidence-based use of micronized progesterone

An issue of habitual miscarriage poses a high social importance especially during COVID-19 pandemic. Meanwhile, healthcareworkers faced a mass media campaign against using micronized progesterone upon habitual miscarriage, which, as viewed by us, displays signs of prejudiced data manipulation and may disorient practitioners. In this Letter we provide objective information on accumulated data regarding gestagenes efficacy and safety. We invoke healthcare professionals to make decisions deserving independent primary source trust presented by original scientific papers published in peer-reviewed journals, clinical recommendations proposed by professional medical communities as well as treatment standards and protocols.

Prediction of preterm birth: the role cervical assessment by ultrasound and cervico-vaginal biomarkers

Preterm delivery (PTB) is one of the most common and serious complications of pregnancy. PTB accounts for approximately 70% of neonatal deaths and is a major cause of neonatal morbidity including respiratory distress syndrome, necrotising enterocolitis and long-term neurological disabilities. Prevention of PTB and its complications include identification among symptomatic women those at high risk of immediate delivery requiring prenatal corticosteroids administration. Transvaginal ultrasonographic evaluation of the cervical length (CL) is predictive of PTB and a value 15 mm identifies among symptomatic women approximately 70% of women who will deliver within one week. In the range of CL within 15 and 30 mm biomarkers n cervical-vaginal fluids (fetal fibronectin, phosphorylated insulin-like growth factor protein-1, placental alpha-microglobulin-, cytokines) and other ultrasonographic cervical variables (posterior cervical angle, elastography) improve the identification of women at risk, In asymptomatic women CL can be applied as screening and has been proposed as a universal screening during the second trimester in singleton gestations. The finding of a CL25mm is associated with an increased risk of subsequent PTB with a sensitivity between 30 and 60% that is improved with the combination of biomarkers. Asymptomatic women with a CL 25mm should be offered vaginal progesterone treatment for the prevention of preterm birth and neonatal morbidity. The role of cerclage and pessary is still controversial. In this review we discuss the evidence-based role of ultrasonographic cervical assessment and cervicovaginal biomarkers in the prediction of PTB in symptomatic and asymptomatic women

Pregnancy and delivery in women with a high risk of infection in pregnancy

Background: Pregnant women with chronic genital and non-genital infections are at a high risk of infections complication during pregnancy and the postpartum period. Preterm birth is one of the leading causes of obstetric and neonatal complications and occurs in one in nine women. Forty per cent of preterm births are considered to be caused by the abnormal vaginal microbiome, and there is currently no consensus on the contribution of combined bacterial and viral infections.Aim: To assess the course of pregnancy and delivery in women with a high risk of chronic infections and the association with the presence of specific microorganisms in the genital microbiome.Materials and methods: We performed a prospective controlled observational study in 355 pregnant women with a high risk of chronic infections. The high risk was defined as presence acute or chronic genital or extragenital infections, reactivation of chronic infections/inflammatory diseases during current pregnancy and history of obstetric complications during previous pregnancies such as miscarriages, missed miscarriages, preterm deliveries, postpartum endometritis, and sepsis.Results: In women with a high risk of chronic infections, pregnancy was associated with recurrent threatened pregnancy loss (49.8%), preterm premature rupture of fetal membranes (64.3%), followed by prolonged oligohydramnios. Almost in one in two women (47.9%), pregnancy resulted in the delivery of preterm, low-birth-weight neonates. One in three women (30%) experienced uterine hypotony and bleeding after vaginal and cesarean delivery. Almost a third of women (32.1%) developed inflammatory complications postpartum, and more than half of complications (54.4%) was observed in women giving birth prematurely. Vaginal and cervical cultures in women who experienced preterm birth were dominated by non-obligate pathogens. We observed persistence of the Herpesviridae family both in the cervical canal and uterine cavity, specifically the Epstein-Barr virus (17.2%; 95% CI: 10%, 26.8%).Conclusions: Pregnancies in women with a high risk of chronic infections were associated with high rates of recurrent threatened pregnancy loss, preterm rupture of membranes and preterm delivery.

Dysregulation of bile acids increases the risk for preterm birth in pregnant women

Preterm birth (PTB) is the leading cause of perinatal mortality and newborn complications. Bile acids are recognized as signaling molecules regulating a myriad of cellular and metabolic activities but have not been etiologically linked to PTB. In this study, a hospital-based cohort study with 36,755 pregnant women is conducted. We find that serum total bile acid levels directly correlate with the PTB rates regardless of the characteristics of the subjects and etiologies of liver disorders. Consistent with the findings from pregnant women, PTB is successfully reproduced in mice with liver injuries and dysregulated bile acids. More importantly, bile acids dose-dependently induce PTB with minimal hepatotoxicity. Furthermore, restoring bile acid homeostasis by farnesoid X receptor activation markedly reduces PTB and dramatically improves newborn survival rates. The findings thus establish an etiologic link between bile acids and PTB, and open an avenue for developing etiology-based therapies to prevent or delay PTB.

Use of complete blood count for predicting preterm birth in asymptomatic pregnant women: A propensity score-matched analysis

Background

Accurate prediction of preterm birth (PTB) is still difficult, mostly because of the multifactorial etiology of PTB. Previous studies have been mostly focused on the prediction of PTB in symptomatic women or those presenting with threatened preterm labor. We aimed to study whether complete blood count (CBC) parameters at 20‐30 weeks of pregnancy can predict asymptomatic PTB.

Methods

In this retrospective case‐control study, the preterm and term delivery groups were matched by propensity score‐matched (PSM) analysis. Baseline data and the CBC parameters examined at 20‐30 weeks of gestation were recorded.

Results

The combined marker of neutrophil‐to‐lymphocyte ratio (NLR), hemoglobin (HGB), and platelet distribution width (PDW) accurately predicts PTB at a cutoff value of 0.25, with sensitivity and specificity of 88.6% and 40.5% and negative and positive predictive value of 97.9% and 10.2%, respectively.

Conclusion

The combined marker of CBC parameters can supplement other markers to predict PTB about 10 weeks in advance. This combined marker had a very high negative predictive value for PTB. Therefore, in subjects with normal combined marker value, further screening tests for PTB may be eliminated unless clinical suspicion is high.

Combination of the placental alpha-1 microglobulin test and ultrasonic cervical length measurement to predict the time of preterm birth

OBJECTIVE

To evaluate the combined identification of placental alpha-1 microglobulin (PAMG-1) in cervicovaginal secretions and ultrasound cervical length measurement in pregnant women with symptoms of threatening premature bith (PB) and intact fetal membranes to predict the time of labor onset.

MATERIALS AND METHODS

A prospective observational study including 137 pregnant women at a gestational age of 22-37 weeks with symptoms of PB. Presence of PAMG-1 was determined using the commercially available PartoSure test kit (Parsagen Diagnostics Inc, Boston, USA) and the cervical length was measured using ultrasound.

RESULTS

Ultrasound cervicometry in women with the cervical length between 15 and 30 mm had a positive predictive value of only 8.9% for PB within 7 and 14 days. The PartoSure test in women with the cervical length between 15 and 30 mm had the positive predictive value for PB within 7 and 14 days of 63.6%.

CONCLUSION

Using the combination of ultrasound cervicometry and PAMG-1 testing in women with symptoms of PB and the cervical length between 15 and 30 mm may allow to identify those with a high risk of PB within 7 and 14 days more accurately.

Evaluation of placental alpha microglobulin-1(PAMG1) accuracy for prediction of preterm delivery in women with the symptoms of spontaneous preterm labor; a comparison with cervical length and number of contractions

Introduction: Since the capacity of tertiary centers is limited, identifying women with the risk of preterm delivery is crucial amongst women who refer to hospitals with threatened preterm labor.Objective: The purpose of the present study was to evaluate the accuracy of the placental alpha microglobulin-1 (PAMG-1) test for identifying women who referred to hospitals with signs of spontaneous preterm labor and ultimately delivered within ≤48 h and ≤7 of testing and ≤37 weeks of gestation and its comparison with cervical length of <25 mm and number of contractions.Materials and methods: A prospective observational study was performed on women with the signs of spontaneous preterm labor. Placental alpha microglobulin-1 (PAMG-1) was evaluated in vaginal secretion. Cervical length (CL) and number of contractions were evaluated and recorded. The test to- spontaneous- delivery interval was documented. Sensitivity (SN), specificity (SP), accuracy rate of the PAMG-1, cervical length of <25 mm and number of contractions in prediction of spontaneous preterm delivery within ≤48 h, ≤7 days and preterm delivery (≤37 weeks of gestation) were calculated.Results: One hundred eighty women finished the study. 44 women had positive PAMG-1 test and 58 women had cervical length of <25 mm. Women with a positive PAMG-1 were more likely to deliver within ≤48 h (p < .0001), ≤7 days (p < .0001), and before 37 weeks (p < .0001), compared to the women who had a negative test. For delivery within ≤48 h, ≤7 days and ≤37 weeks, specificity (SP) of the PAMG-1; was statistically higher than cervical length of <25 mm and contractions of 12-17/hr but not contractions of ≥18/hr. PAMG-1 showed a higher accuracy rate than cervical length of <25 mm, contractions of 12-17/hr and contractions of ≥18/hr for deliveries within ≤48 h (78.9, 55.3, 48.9, and 69.44%, respectively) and ≤7 days (76.1, 55.32, 55, and 65.56%, respectively). For deliveries before 37 weeks; the PAMG-1 test showed higher LR + than CL of <25 mm, contractions of 12-17/hr and contractions of ≥18/hr [10.24 (2.57-40.86), 2.01 (1.24-3.23), 1.30 (1.05-1.62), and 5.12 (1.24-21.11), respectively]. PPV for deliveries within ≤48 h and ≤7 days for PAMG-1 was greater than cervical length of <25 mm and number of contractions, however, NPV did not show a significant difference.Conclusion: PAMG-1 test showed a higher accuracy rate for prediction of delivery within ≤48 and ≤7 days in comparison with cervical length of <25 mm and number of contractions. Also, PAMG-1 test had a higher positive likelihood ratio for deliveries at ≤37 weeks. PPV for deliveries within ≤48 h and ≤7 days for PAMG-1 was greater than cervical length of <25 mm and number of contractions, however, NPV did not show a significant difference.

Maternal pulmonary edema after 46 h of ritodrine hydrochloride administration: A case report

Introduction

Ritodrine hydrochloride is still widely used as a tocolytic agent in Japan, but it can cause maternal pulmonary edema, which may paradoxically induce preterm birth. Here we present a case of severe pulmonary edema due to <48 h of ritodrine administration.

Case

A 46-year-old woman was diagnosed with threatened preterm labor (TPL) and placenta previa at 26 weeks of gestation. She had mild uterine contractions and genital bleeding. Ritodrine hydrochloride, magnesium sulfate, and betamethasone were administered. She developed dyspnea 46 h after starting ritodrine administration. Chest X-ray showed pulmonary edema. Even after cessation of ritodrine, dyspnea did not lessen and there were regular uterine contractions with abdominal pain. Emergency caesarean section was performed. A female neonate was delivered and admitted to the neonatal intensive care unit. After surgery, maternal dyspnea decreased without any complications.

Discussion

Excessive use of ritodrine or its use in combination with other tocolytic agents can cause maternal pulmonary edema, even with <48 h of use. Adverse maternal side-effects and rebound uterine contractions due to cessation of ritodrine may paradoxically trigger preterm birth. Strict patient selection for tocolytic therapy is essential and ritodrine requires caution because of its potential side-effects.

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Ritodrine hydrochloride is still widely used as a tocolytic agent in Japan.

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Ritodrine can cause maternal pulmonary edema, even with <48 h of administration.

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Strict patient selection for tocolysis is essential.

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Ritodrine requires caution because of potential side effects.

Association of modulation of pro-inflammatory responses by dectin-2 with preterm delivery: An experimental model

PROBLEM

Pro-inflammatory responses of pathogen recognition receptors (PRR) are implicated in preterm delivery (PTD). Dectin-2 is one PRR recognizing unselective carbohydrate structures; its participation in PTD has never been studied before.

METHOD OF STUDY

In an experimental model, PTD was induced in female pregnant wild-type (WT) mice and mice with homologous deficiency for dectin-2 by the intraperitoneal injection of bacterial lipopolysaccharide (LPS) on day 14 of pregnancy. Time to delivery and fetal mortality were recorded. Challenged mice were killed for tissue collection and splenocyte isolation 6 hours later. Concentrations of tumour necrosis factor-alpha (TNFα), interleukin (IL)-1α, and IL-1β were measured.

RESULTS

Delivery was induced significantly earlier in WT than dectin-2^-/- mice; however, fetal mortality was higher among dectin-2^-/- mice. Candida albicans challenge could not lead to these changes. Sacrifice experiments showed that LPS challenge led to significant increase of TNFα, IL-1α, and IL-1β in maternal tissues of WT; this was further enhanced for TNFα and IL-1β in dectin-2^-/- mice. Pre-treatment with the prostaglandin inhibitor diclofenac delayed time to delivery of WT mice, but not of dectin2^-/- mice. TNFα stimulation of splenocytes of dectin2^-/- mice was enhanced with the addition of anti-TLR4 and decreased in the presence of lipid A.

CONCLUSIONS

Dectin-2 delays LPS-induced PTD by enhancing the production of pro-inflammatory cytokines.

Pharmacology for Preterm Labor

Preterm birth occurs with 10% of deliveries and yet accounts for more than 85% of perinatal morbidity and mortality. Management of preterm labor prior to delivery includes a multipronged pharmacologic approach targeting utilization of reproductive hormones for continuation of pregnancy, advancement of fetal lung maturity, and the decrease of uterine contractility (tocolysis). This article will review and compare guidelines on pharmacologic management of preterm labor as recommended by the American College of Obstetricians and Gynecologists and the European Association of Perinatal Medicine. The classifications of drugs discussed include exogenous progesterone, corticosteroids, and tocolytics (β-adrenergic agonists, magnesium sulfate, calcium channel blockers, prostaglandin inhibitors, nitrates, and oxytocin receptor blockers). For each of these drug classes, the following information will be presented: mechanism of action, maternal/fetal side effects, and nursing implications.

Mehanizam kontrakcije i relaksacije miometrijuma, interakcija okcitocina i prostaglandina

Regulation of uterine activity during pregnancy is due to the nature of the loss of humoral sympathetic, holinergical and peptidergic inervation. So far, nothing found that would indicated that the mechanism of premature birth and its pathogenesis different from the normal mechanism of delivery, except for different maturity of the fetus. Since a large number of substances that participate in the contraction and relaxation of miometrium (estrogen, progesterone, cortisol, etc.). Today's modern research has focused on prostaglandins and oxytocin, or their interaction. Accepting oxytocin as substance initiation deliveries it is difficult for two reasons: the level of oxytocin in the blood can not lift before the delivery and release of oxytocin remains constant during pregnancy. Oxytocin probably plays a role in support delivery for decidual cells stimulates the synthesis of uterine PGF2a.