简介：AbstractPreterm parturition is the consequence of pathological signals that activate the common pathway of parturition and considered as a syndrome. Many risk factors for spontaneous preterm birth (sPTB) have been identified. Two significant risk factors for sPTB are history of prior sPTB and short cervical length at midtrimester. 17 hydroxyprogesterone caproate, vaginal progesterone, cerclage, and pessary have all been studied for prevention of sPTB. Difference in patient populations likely contributes to the conflicting study results. Further studies are needed to establish strategies in prevention of sPTB in singleton as well as multiple pregnancies.

简介：AbstractThe time of birth is a critical determinant of perinatal and long-term outcomes, and even trans-generational effects. Preterm birth is still the leading cause of infant mortality and morbidity. Unfortunately, rates of preterm birth remain high worldwide. Preterm parturition is a complex syndrome, which can be induced by several factors such as infection, cervical pathology, uterine overdistension, progesterone deficiency, vascular alterations (utero-placental ischemia, decidual hemorrhage), maternal and fetal stress, allograft reaction, allergic phenomena, and probably other several unknown factors. The mechanisms responsible for early labor activation have been partially identified and involve receptors, chemokines, and inflammatory cytokines. It is very useful to understand the cellular and biochemical pathways responsible for preterm labor activation to identify, treat, and prevent negative outcome in a timely manner. Researchers and clinicians play a key role in improving biochemical knowledge on preterm delivery, identifying risk factors, and applying multilevel preventive strategies.

简介：AbstractPreterm birth (PTB) is defined as delivery before completing 37 weeks of gestation. It is the main cause of neonatal morbidity and mortality in the most countries. The inherent cervical length and strength are two main features of the cervix that determine whether or not a pregnant woman is at risk for PTB. Routine transvaginal cervical length screening was recommended for women with singleton pregnancy and history of prior spontaneous PTB, while the issue of universal cervical length screening and the screening in multiple gestations remain an object of debate. Strain sonoelastography and shear-wave sonoelastography have been used to evaluate the cervical stiffness in pregnant women, but the predictive value for PTB still requires further investigations. In this review, we will discuss the measurement methods of cervical length and cervical stiffness, and compare the value of cervical assessment by transvaginal ultrasound for predicting PTB in asymptomatic women.

简介：AbstractObjective:To evaluate the ability of cervical length (CL) at 28-32 weeks of gestation to predict spontaneous preterm delivery and preterm premature rupture of membranes (PPROM).Methods:It was a retrospective cohort study that vaginal ultrasonography at approximately 28-32 weeks of gestation was performed in 14,953 women between 17-49 years old with singleton pregnancies who delivered after 28 weeks of gestation at the Peking University First Hospital from June 2008 to December 2012. The pregnancy outcomes were followed and the relationship between the CL and preterm delivery or PPROM was assessed. The relative risk was calculated to assess group differences in the likelihood of an event occurring.Results:The overall prevalence of preterm delivery was 5.7% (858/14,953); the incidence for therapeutic preterm delivery was 2.1% (318/14,953), for spontaneous preterm delivery was 0.9% (133/14,953), and for PPROM was 2.7% (407/14,953). Excluding the 318 women who had therapeutic preterm delivery, the relative risk of preterm delivery for women with a CL between 25 mm and <30 mm, between 15 mm and <25 mm, and <15 mm was 3.7, 9.3, and 30.2, respectively. The sensitivity, specificity, and positive and negative predictive values of CL ≤25 mm at 28-32 weeks of gestation as the cut-off value for predicting preterm delivery were 19.8%, 97.5%, 23.4%, and 96.9%, respectively. For preterm delivery before 35 weeks of gestation, the sensitivity, specificity, and positive and negative predictive values of a CL ≤ 25 mm at 28-32 weeks of gestation as the cut-off value were 30.0%, 97.2%, 11.8%, and 99.1%, respectively. In addition, women with PPROM (n = 407) had significantly shorter CL (31.9 ± 7.4) mm at 28-32 weeks of gestation compared that of women without PPROM (34.0 ± 8.3) mm. The incidence of PPROM in women with a CL ≤25 mm at 28-32 weeks of gestation (19.4%, 79/407) was significantly lower than that for women with a CL >25 mm (80.6%, 328/407, P < 0.05).Conclusion:CL at 28-32 weeks of gestation can predict spontaneous preterm delivery, and is valuable for predicting PPROM.

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简介：AbstractObjective:To characterize and compare the microbiome signature in the maternal, intrauterine, and fetal environments and the associated bacterial species in women who experienced preterm birth and term birth.Methods:A total of 140 women with singleton pregnancies were enrolled in this study. Among them, 31 experienced spontaneous preterm delivery (gestational age < 37 weeks), and 28 of them experienced vaginal delivery at term. Maternal peripheral blood, saliva, and vaginal discharge samples and fetal membrane, amniotic fluid, and cord blood samples were collected immediately after delivery under sterile conditions. DNA was isolated from the fetal membrane and umbilical cord blood samples, and the V3-V4 region of the bacterial 16S rRNA gene was sequenced. The sequence data were quality-filtered, chimera-checked, and organized into operational taxonomic units (OTUs) based on phylogeny. Principal coordinate analysis of beta diversity measures was used for visualization. The linear discriminant analysis effect size (LEfSe) algorithm and Wilcoxon test were used to differentiate the microbiomes found in the fetal membranes and cord blood in the cases of preterm birth.Results:OTU analysis based on the 16S rRNA gene showed similar microbiomes in the maternal peripheral blood, amniotic fluid, fetal membranes, and cord blood. However, the LEfSe algorithm revealed significantly different bacterial compositions in the fetal environment between the preterm and term groups, with some of the bacterial species originating from the maternal peripheral blood or saliva.Conclusions:The bacteria in the intrauterine and fetal environments may originate from other body sites through hematogenous transmission, and may cause the occurrence of preterm birth.

简介：AbstractObjective:This study aimed to determine: (1) whether recurrent deliveries of a small for gestational age (SGA) neonate are associated with increased obstetrical or neonatal complications; (2) whether the risk factors that can predict small for gestational age (SGA) recurrence.Methods:This study was based on Soroka Medical Center' s Obstetrics electronic database. The database consisted of 109 022 women who had 320 932 deliveries between the year 1988-2014.The study cohort included 6.8% (7 368/109 022) of these patients who gave birth to a singleton SGA neonate on their first delivery and had more than one delivery. The study population was divided into two groups according to the outcome of the subsequent delivery: (1) women with sporadic SGA who delivered a non-SGA neonate (n= 5 416); (2) women with recurrent SGA (n = 1 952). SGA defined as birthweight <10th percentile. Maternal and neonatal complications were compared between the two groups. Logistic regression was used to determine independent risk factors for SGA recurrence.Results:The prevalence of birthweight <5th percentile was higher among the recurrent SGA group in the first delivery (P < 0.001). Bedouin ethnicity was more prevalent in the recurrent SGA group (P < 0.001). The rate of preterm delivery was higher in the first delivery of the recurrent SGA group (P = 0.015). The sporadic SGA group had a higher rate of perinatal mortality during the first pregnancy (P= 0.017). The rate of severe hypertension (P= 0.005), polyhydramnios, meconium-stained amniotic fluid, nonreassuring fetal heart rate and total perinatal mortality (P < 0.001) were higher in the second delivery of the recurrent SGA group. In a logistic regression model, preterm delivery and birthweight <5th percentile at the first delivery was found to be independent risk factors for recurrence of an SGA neonate in the subsequent birth (relative risks:1.530, confidence interval: 1.249-1.875; relative risks:1.826, confidence interval: 1.641-2.030, respectively).Conclusion:Women with recurrent SGA neonates have specific clinical characteristics. Among women who deliver an SGA neonate, preterm delivery, and birthweight <5th percentile are independent predictors for its recurrence.

简介：AbstractBackground:Delivery room resuscitation assists preterm infants, especially extremely preterm infants (EPI) and extremely low birth weight infants (ELBWI), in breathing support, while it potentially exerts a negative impact on the lungs and outcomes of preterm infants. This study aimed to assess delivery room resuscitation and discharge outcomes of EPI and ELBWI in China.Methods:The clinical data of EPI (gestational age [GA] <28 weeks) and ELBWI (birth weight [BW] <1000 g), admitted within 72 h of birth in 33 neonatal intensive care units from five provinces and cities in North China between 2017 and 2018, were analyzed. The primary outcomes were delivery room resuscitation and risk factors for delivery room intubation (DRI). The secondary outcomes were survival rates, incidence of bronchopulmonary dysplasia (BPD), and risk factors for BPD.Results:A cohort of 952 preterm infants were enrolled. The incidence of DRI, chest compressions, and administration of epinephrine was 55.9% (532/952), 12.5% (119/952), and 7.0% (67/952), respectively. Multivariate analysis revealed that the risk factors for DRI were GA <28 weeks (odds ratio [OR], 3.147; 95% confidence interval [CI], 2.082-4.755), BW <1000 g (OR, 2.240; 95% CI, 1.606-3.125), and antepartum infection (OR, 1.429; 95% CI, 1.044-1.956). The survival rate was 65.9% (627/952) and was dependent on GA. The rate of BPD was 29.3% (181/627). Multivariate analysis showed that the risk factors for BPD were male (OR, 1.603; 95% CI, 1.061-2.424), DRI (OR, 2.094; 95% CI, 1.328-3.303), respiratory distress syndrome exposed to ≥2 doses of pulmonary surfactants (PS; OR, 2.700; 95% CI, 1.679-4.343), and mechanical ventilation ≥7 days (OR, 4.358; 95% CI, 2.777-6.837). However, a larger BW (OR, 0.998; 95% CI, 0.996-0.999), antenatal steroid (OR, 0.577; 95% CI, 0.379-0.880), and PS use in the delivery room (OR, 0.273; 95% CI, 0.160-0.467) were preventive factors for BPD (all P < 0.05).Conclusion:Improving delivery room resuscitation and management of respiratory complications are imperative during early management of the health of EPI and ELBWI.

简介：ASpecializedCommitteeofREInforma-tionundertheChineseRESocietyhasbeenformedwiththepurposeofstreng-theningtheexchangeofREinformationandpromotingthedevelopmentofREsci-enceandtechnologyathomeandabroad.ThefirstmeetingofthecommitteewasheldinBeijingonDecember23-25,1989,andwasattendedbyover100representa-tivesfromuniversitiesandscientificresearchinstitutionsinvariouspartsofChina.Amongthemweresomewell-knownscholarswhohavelongbeenengagedin

简介：In1946,WorldWarⅡhadjustrecentlyended.Moreandmorepeoplewerefloodingtosportingevents,especiallycollegebasketball.MaxKase,asportseditoroftheNewYorktoldtheowneroftheNationalHockeyLeague,WalterBrown,abouthisidea,andBrowntookthei-deatoNedIrish.Nedstatedhewasalreadyworkingonsuchaleague,andKasedideventuallyreceiveseveralthousanddollarsforhisefforts.

简介：Thedemographicstructureofpopulations,particularlyageandsex,hasprofoundconsequencesforharmoniousandsustainablesocialandeconomicdevelopment.Furthermore,analyzingsexratiosofpopulationsisimportantinanalyzingthedevelopmentofthestatusOfwomenandgirls.

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简介：教学目标1.学生能够在谈论生肖的活动中巩固、复习本单元词汇和短语,并正确运用;2.学生能够在谈论生肖这一语境中运用功能句型表达十二生肖的轮回、顺序及生肖特征;3.学生能够在推算年龄、制作海报等活动中,利用单元所学语言表达和交流十二生肖传统文化,体会中国传统文化的智慧。教学重点与难点(一)重点1.熟练掌握十二生肖的名称,轮回频率,顺序及生肖特征;

简介：Sincethe1980s,especiallythemid-1980s,theimbalanceinthesexratioatbirthinChinahasbeenincreasingcontinuouslyandthesituationhasworsenedinrecentyears,accordingtothefourthandfifthcensusesin1990and2000.Thisissuehasdrawnwidespreadattentionfromthegovernmentaswellasacademia.Thefundamentalreasonfortheimbalance

简介：AbstractPreterm labor (before 37 weeks’ gestation) is the leading cause of neonatal mortality and morbidity, which can be divided into iatrogenic preterm labor, infectious preterm labor, and spontaneous preterm labor (sPTL). Up to now, there continue to be great difficulties in prediction and prevention of sPTL, owing to multiple risk factors, pathogenesis, and pathologic processes contributing to the event, which have not been fully clarified. Pregnancy maintenance and parturition is a complicated process with continuous maternal-fetal dialogue, in which both maternal and fetal factors participate and affect the outcome of pregnancy, including sPTL. Besides, external factors can also participate in sPTL, individually or through the interaction with internal factors. In this article, we summarize recent studies regarding sPTL from our and other groups, and discuss the risk factors and pathogenesis of preterm birth from both external and internal (maternal and fetal) aspects, so as to provide theoretical evidences for the diagnosis, prevention, and treatment of sPTL in the future.

简介：WeconsideroptimalbirthcontrolfortheMcKendrickequationofpopulationdyna-mics.Itconsistsofoptimizingasystemdescribedbyafirstorderpartialdifferentialequationwithnonlo-calbilinearboundarycontrol.ApproximateminimumprinciplesareobtainedusingEkeland’svariationalprinciple.

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简介：OBJECTIVE:Ameta-analysisofpublishedrandomizedcontrolledtrialsinvestigatingthelongtermeffectofdexamethasoneonthenervoussystemofpreterminfants.DATASOURCES:OnlineliteratureretrievalwasconductedusingTheCochraneLibrary(fromJanuary1993toJune2013),EMBASE(fromJanuary1980toJune2013),MEDLINE(fromJanuary1963toJune2013),OVID(fromJanuary1993toJune2013),Springer(fromJanuary1994toJune2013)andChineseAcademicJournalFull-textDatabase(fromJanuary1994toJune2013).KeywordswerepreterminfantsanddexamethasoneinEnglishandChinese.STUDYSELECTION:Selectedstudieswererandomizedcontrolledtrialsassessingtheeffectofintravenousdexamethasoneinpreterminfants.Thequalityoftheincludedpaperswasevaluatedandthosewithoutthedevelopmentofthenervoussystemandanimalexperimentswereexcluded.QualityassessmentwasperformedthroughbiasriskevaluationinaccordancewithCochraneHandbook5.1.0softwareintheCochraneCollaboration.ThehomogeneousstudieswereanalyzedandcomparedusingRevman5.2.6software,andtheneffectmodelwasselectedandanalyzed.Thosepapersfailedtobeincludedinthemeta-analysisweresubjectedtodescriptiveanalysis.MAINOUTCOMEMEASURES:Nervoussysteminjuryinpreterminfants.RESULTS:Tenrandomizedcontrolledtrialswerescreened,involving1,038subjects.Amongthem512casesreceiveddexamethasonetreatmentwhile526casesservedasplacebocontrolgroupandblankcontrolgroup.Meta-analysisresultsshowedthattheincidenceofcerebralpalsy,visualimpairmentandhearinglossinpreterminfantsafterdexamethasonetreatmentwithin7daysafterbirthwassimilartothatinthecontrolgroup(RR=1.47,95%CI:0.97–2.21;RR=1.46,95%CI:0.97–2.20;RR=0.80,95%CI:0.54–1.18;P>0.05),butintelligencequotientwassignificantlydecreasedcomparedwiththecontrolgroup(MD=-3.55,95%CI:-6.59to-0.51;P=0.02).Preterminfantstreatedwithdexamethasone7daysafterbirthdemonstratedaninci

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