Clinical risk factors for preterm birth and evaluating maternal psychology in the postpartum period

BACKGROUND Although the specific pathogenesis of preterm birth(PTB)has not been thoroughly clarified,it is known to be related to various factors,such as pregnancy complications,maternal socioeconomic factors,lifestyle habits,reproductive history,environmental and psychological factors,prenatal care,and nutritional status.PTB has serious implications for newborns and families and is associated with high mortality and complications.Therefore,the prediction of PTB risk can facilitate early intervention and reduce its resultant adverse consequences.AIM To analyze the risk factors for PTB to establish a PTB risk prediction model and to assess postpartum anxiety and depression in mothers.METHODS A retrospective analysis of 648 consecutive parturients who delivered at Shenzhen Bao’an District Songgang People’s Hospital between January 2019 and January 2022 was performed.According to the diagnostic criteria for premature infants,the parturients were divided into a PTB group(n=60)and a full-term(FT)group(n=588).Puerperae were assessed by the Self-rating Anxiety Scale(SAS)and Self rating Depression Scale(SDS),based on which the mothers with anxiety and depression symptoms were screened for further analysis.The factors affecting PTB were analyzed by univariate analysis,and the related risk factors were identified by logistic regression.RESULTS According to univariate analysis,the PTB group was older than the FT group,with a smaller weight change and greater proportions of women who underwent artificial insemination and had gestational diabetes mellitus(P<0.05).In addition,greater proportions of women with reproductive tract infections and greater white blood cell(WBC)counts(P<0.05),shorter cervical lengths in the second trimester and lower neutrophil percentages(P<0.001)were detected in the PTB group than in the FT group.The PTB group exhibited higher postpartum SAS and SDS scores than did the FT group(P<0.0001),with a higher number of mothers experiencing anxiety and depression(P<0.001).Multivariate logistic regression analysis revealed that a greater maternal weight change,the presence of gestational diabetes mellitus,a shorter cervical length in the second trimester,a greater WBC count,and the presence of maternal anxiety and depression were risk factors for PTB(P<0.01).Moreover,the risk score of the FT group was lower than that of the PTB group,and the area under the curve of the risk score for predicting PTB was greater than 0.9.CONCLUSION This study highlights the complex interplay between postpartum anxiety and PTB,where maternal anxiety may be a potential risk factor for PTB,with PTB potentially increasing the incidence of postpartum anxiety in mothers.In addition,a greater maternal weight change,the presence of gestational diabetes mellitus,a shorter cervical length,a greater WBC count,and postpartum anxiety and depression were identified as risk factors for PTB.

A Comparison between Late Preterm and Term Infants with Respiratory Distress Syndrome, Early-Onset Sepsis, and Neonatal Jaundice in Ecuadorian Newborns

Background: To examine the differences in prevalence of respiratory distress syndrome, early-onset sepsis and jaundice, between late preterm infants versus term infants in Ecuadorian newborns. Methods: Study design: Epidemiological, observational, and cross-sectional, with two cohorts of patients. Settings: IESS Quito Sur Hospital at Quito, Ecuador, from February to April of 2020. Participants: This study included 204 newborns, 102 preterm infants, 102 term infants. Results: There are significant differences between late preterm infants and term infants, with a p-value of 0.000 in the prevalence of early sepsis, 70.59% vs. 35.29%. In respiratory distress syndrome between late and term premature infants, significant differences were observed with a p-value of 0.000, the proportion being 55.58% vs. 24.51% respectively. The prevalence of jaundice is higher in term infants with a p value of 0.002, 72.55%, versus 51.96% in late preterm infants, and the mean value of bilirubins in mg/dL was higher in term infants 14.32 versus 12.33 in late preterm infants;this difference is statistically significant with a p value of 0.004. Admission to the NICU is more frequent in late preterm infants with a p-value of 0.000, being 42.16% for late preterm infants vs. 7.84% in term infants;the mean of the hospital days with p-value 0.005, was higher in late preterm infants 4.97 days vs. 3.55 days for term newborns. Conclusion: Due to the conditions of their immaturity, late preterm infants are 2.86 times more likely to present early sepsis than full-term newborns. It is shown that late preterm infants are 2.69 times more likely to have respiratory distress syndrome compared to term infants, therefore, late preterm infants have a longer hospital stay of 4.97 days versus 3.55 days in term infants. Jaundice and mean bilirubin levels are higher in term infants due to blood group incompatibility and insufficient breastfeeding.

Evaluating the Efficacy of Cervical Tactile Ultrasound Technique as a Predictive Tool for Spontaneous Preterm Birth

Background: Premature cervical softening and shortening may be considered an early mechanical failure that predispose to preterm birth. Purpose: This study aims to explore the applicability of an innovative cervical tactile ultrasound approach for predicting spontaneous preterm birth (sPTB). Materials and Methods: Eligible participants were women with low-risk singleton pregnancies in their second trimester, enrolled in this prospective observational study. A Cervix Monitor (CM) device was designed with a vaginal probe comprising four tactile sensors and a single ultrasound transducer operating at 5 MHz. The probe enabled the application of controllable pressure to the external cervical surface, facilitating the acquisition of stress-strain data from both anterior and posterior cervical sectors. Gestational age at delivery was recorded and compared against cervical elasticity. Results: CM examination data were analyzed for 127 women at 240/7 - 286/7 gestational weeks. sPTB was observed in 6.3% of the cases. The preterm group exhibited a lower average cervical stress-to-strain ratio (elasticity) of 0.70 ± 0.26 kPa/mm compared to the term group’s 1.63 ± 0.65 kPa/mm with a p-value of 1.1 × 10−4. Diagnostic accuracy for predicting spontaneous preterm birth based solely on cervical elasticity data was found to be 95.0% (95% CI, 88.5 - 100.0). Conclusion: These findings suggest that measuring cervical elasticity with the designed tactile ultrasound probe has the potential to predict spontaneous preterm birth in a cost-effective manner.

Gut microbiota in preterm infants receiving breast milk or mixed feeding

BACKGROUND Preterm birth is the leading cause of mortality in newborns,with very-low-birthweight infants usually experiencing several complications.Breast milk is considered the gold standard of nutrition,especially for preterm infants with delayed gut colonization,because it contains beneficial microorganisms,such as Lactobacilli and Bifidobacteria.AIM To analyze the gut microbiota of breastfed preterm infants with a birth weight of 1500 g or less.METHODS An observational study was performed on preterm infants with up to 36.6 wk of gestation and a birth weight of 1500 g or less,born at the University Hospital Dr.JoséEleuterio González at Monterrey,Mexico.A total of 40 preterm neonates were classified into breast milk feeding(BM)and mixed feeding(MF)groups(21 in the BM group and 19 in the MF group),from October 2017 to June 2019.Fecal samples were collected before they were introduced to any feeding type.After full enteral feeding was achieved,the composition of the gut microbiota was analyzed using 16S rRNA gene sequencing.Numerical variables were compared using Student’s t-test or using the Mann–Whitney U test for nonparametric variables.Dominance,evenness,equitability,Margalef’s index,Fisher’s alpha,Chao-1 index,and Shannon’s diversity index were also calculated.RESULTS No significant differences were observed at the genus level between the groups.Class comparison indicated higher counts of Alphaproteobacteria and Betaproteobacteria in the initial compared to the final sample of the BM group(P<0.011).In addition,higher counts of Gammaproteobacteria were detected in the final than in the initial sample(P=0.040).According to the Margalef index,Fisher’s alpha,and Chao-1 index,a decrease in species richness from the initial to the final sample,regardless of the feeding type,was observed(P<0.050).The four predominant phyla were Bacteroidetes,Actinobacteria,Firmicutes,and Proteobacteria,with Proteobacteria being the most abundant.However,no significant differences were observed between the initial and final samples at the phylum level.CONCLUSION Breastfeeding is associated with a decrease in Alphaproteobacteria and Betaproteobacteria and an increase of Gammaproteobacteria,contributing to the literature of the gut microbiota structure of very low-birth-weight,preterm.

Study on the Effect of Early Oral Motor Intervention in Preterm Infants in Neonatal Intensive Care Unit

Objective:To study the effective value of introducing the concept of early oral exercise in the process of nursing intervention for preterm infants in the neonatal intensive care unit(NICU).Methods:96 cases of preterm infants diagnosed from January 2022 to August 2022 were selected and randomly divided into two groups:the general practice group(general nursing intervention),and the early practice group(early oral exercise intervention),and the effect of intervention on preterm infants in the two groups was observed.Results:After nursing care,the mean value of the non-nutritive sucking ability assessment(76.54±5.82),the mean value of the intellectual development degree assessment(104.57±8.45),the mean value of the psychomotor development degree assessment(102.33±6.74),and the mean value of behavioral neural reflexes ability assessment(38.71±2.40)in the early practice group were better than that as compared to the general practice group(P<0.05);the mean value of oral feeding start time of preterm infants in the early practice group(35.42±7.63)weeks,the mean value of all oral feeding time(34.12±5.28)weeks,and the mean time of hospital intervention(15.33±4.25)days were lesser than compared to those of the general practice group at 37.4±5.82 weeks,37.46±3.55 weeks,and 20.46±2.91 days,respectively(P<0.05);the rate of adverse reactions in preterm infants in the early practice group significantly lower than that of the general practice group(P<0.05).Conclusion:The introduction of the concept of early oral exercise intervention among NICU nurses improved the feeding effect,sucking ability of preterm infants,and intellectual development.Hence,early oral motor care should be popularized.

New Interpretation of Neonatal Outcomes by Phenotypically Classified Preterm Syndrome:A Retrospective Cohort Study

Objective:The global aim to lower preterm birth rates has been hampered by the insufficient and incomplete understanding of its etiology,classification,and diagnosis.This study was designed to evaluate the association of phenotypically classified preterm syndromes with neonatal outcomes;to what extent would these outcomes be modified after the obstetric interventions,including use of glucocorticoid,magnesium sulfate,and progesterone.Methods:This was a retrospective cohort study conducted at Tongji Hospital(composed of Main Branch,Optical Valley Branch and Sino-French New City Branch)in Wuhan.A total of 900 pregnant women and 1064 neonates were retrospectively enrolled.The outcomes were the distribution of different phenotypes among parturition signs and pathway to delivery,the association of phenotypically classified clusters with short-term unfavorable neonatal outcomes,and to what extent these outcomes could be modified by obstetric interventions.Results:Eight clusters were identified using two-step cluster analysis,including premature rupture of fetal membranes(PPROM)phenotype,abnormal amniotic fluid(AF)phenotype,placenta previa phenotype,mixed condition phenotype,fetal distress phenotype,preeclampsia-eclampsia&hemolysis,elevated liver enzymes,and low platelets syndrome(PE-E&HELLP)phenotype,multiple fetus phenotype,and no main condition phenotype.Except for no main condition phenotype,the other phenotypes were associated with one or more complications,which conforms to the clinical practice.Compared with no main condition phenotype,some phenotypes were significantly associated with short-term adverse neonatal outcomes.Abnormal AF phenotype,mixed condition phenotype,PE-E&HELLP phenotype,and multiple fetus phenotype were risk factors for neonatal small-for gestation age(SGA);placenta previa phenotype was not associated with adverse outcomes except low APGAR score being 0-7 at one min;mixed condition phenotype was associated with low APGAR scores,SGA,mechanical ventilation,and gradeⅢ-Ⅳintraventricular hemorrhage(IVH);fetal distress phenotype was frequently associated with neonatal SGA and mechanical ventilation;PE-E&HELLP phenotype was correlated with low APGAR score being 0-7 at one min,SGA and neonatal intensive care unit(NICU)admission;multiple fetus phenotype was not a risk factor for the outcomes included except for SGA.Not all neonates benefited from obstetric interventions included in this study.Conclusion:Our research disclosed the independent risk of different preterm phenotypes for adverse pregnancy outcomes.This study is devoted to putting forward the paradigm of classifying preterm birth phenotypically,with the ultimate purpose of defining preterm phenotypes based on multi-center studies and diving into the underlying mechanisms.

Transcatheter Closure vs.Surgical Ligation in Preterm Infants with Patent Ductus Arteriosus:A Systematic Review and Meta-Analysis

Background:Persistent patent ductus arteriosus(pPDA)is a common condition in preterm infants.This metaanalysis aimed to assess the safety and efficacy of transcatheter closure(TC)when compared to surgical ligation(SL)in preterm infants with pPDA.Methods:A literature search of Ovid Cochrane Library,Medline,Embase,Epub,Scopus,PMC Preprints,and ClinicalTrials.Gov was conducted from inception to May 06,2022.Eligible studies reported infants diagnosed with pPDA born at≤2000 g birth weight or at≤37 weeks’who underwent TC or SL as treatment.This review was registered in PROSPERO(CRD42022325944).Results:From 97 studies screened,8 studies met the eligibility criteria,with a total of 756 preterm infants undergoing either TC(n=366)or SL(n=390).Compared to TC,SL had higher mortality rates(OR=0.32,95%CI:0.16,0.66,I^(2)=0%).No difference was seen in post-procedural complication rate(OR=0.90,95%CI:0.18,4.44,I^(2)=79%),mean duration of post-procedural mechanical ventilation(MD=−2.21 days,95%CI:−4.88,0.47,I^(2)=60%),hospital stay length(MD=−8.30 days,95%CI:−17.03,0.44,I^(2)=0%)or neonatal intensive care unit stay length(MD=−3.50 days,95%CI:−10.27,3.27,I^(2)=0%).Conclusion:Our meta-analysis demonstrated TC as a viable alternative option in managing preterm infants with pPDA in the context of SL.Despite the promising trends demonstrated in this meta-analysis,further studies with larger sample size and controlled baseline characteristics are needed to evaluate the safety and efficacy of TC and SL for preterm infants with pPDA.

Pharmacogenomics-based individualized treatment of hypertension in preterm infants: A case report and review of the literature

BACKGROUND Neonatal hypertension is a rare but potentially serious condition that requires careful monitoring and treatment.Pharmacogenomics can help guide individualized drug therapy and improve outcomes.CASE SUMMARY We report a case of a preterm infant with multiple complications,including bronchopulmonary dysplasia(BPD),sepsis,intracranial hemorrhage,and hypertension.The infant was treated with various drugs,including dexamethasone and amlodipine.The infant was diagnosed with neonatal hypertension based on blood pressure measurements exceeding the 95th percentile for his age and sex.The possible causes of hypertension included dexamethasone,hydrochlorothiazide,spironolactone,and BPD.The infant was treated with oral amlodipine to lower his blood pressure.A pharmacogenomic test was performed to evaluate the genetic polymorphisms of ABCB1 and CYP3A5,which are involved in the metabolism and transport of dexamethasone and amlodipine.The infant’s blood pressure was well controlled after the dose of amlodipine was reduced according to the pharmacogenomic results.The infant had a stable general condition and was discharged on the 100th d after birth.CONCLUSION This case illustrates the importance of regular blood pressure monitoring and etiological investigation in preterm infants with hypertension.Pharmacogenomics can provide useful information for individualized drug therapy and safety in this population.

Enhancing the role of nurses in breastfeeding preterm infants

The provision of breast milk and breastfeeding is recommended for preterm infants.Multidisciplinary cooperation is required to promote breastfeeding.Nurses play impor tant roles in breastfeeding preterm infants.First,nurses are strong advocates to help families be aware of the significance of breastfeeding.Second,nurses are educators providing technical and emotional support to pregnant and lying-in women.Third,nurses are coordinators in a multidisciplinary team.Nurses’unawareness of the impor tance of breastfeeding,knowledge deficit,and unsupportive lactation policy are barriers to breastfeeding promotion for preterm infants.It is therefore suggested that hospital administrators provide appropriate breastfeeding policies,set up posts,and ensure nurses’responsibilities in breastfeeding.Additionally,tailored training should be strengthened to improve nurses’knowledge and skills and thereby enable them to fully exer t their roles in the breastfeeding promotion of preterm infants.

Lamellar Bodies Count (LBC) as a Predictor of Fetal Lung Maturity in Preterm Premature Rupture of Membranes Compared to Neonatal Assessment

Background: Respiratory distress syndrome (RDS) is a major cause of neonatal morbidity and mortality, affecting approximately 1% of all live births and 10% of all preterm infants. Lamellar bodies represent a storage form of pulmonary surfactant within Type II pneumocytes, secretion of which increases with advancing gestational age, thus enabling prediction of the degree of FLM. Preterm premature rupture of membranes (PPROM) complicates approximately 1/3 of all preterm births. Birth within 1 week is the most likely outcome for any patient with PPROM in the absence of adjunctive treatments. Respiratory distress has been reported to be the most common complication of preterm birth. Sepsis, intraventricular haemorrhage, and necrotizing enterocolitis also are associated with prematurity, but these are less common near to term. Objective: To assess the efficacy of the amniotic fluid lamellar body counting from a vaginal pool in predicting fetal lung maturity in women with preterm premature rupture of membranes. Methods: This study was conducted at Ain Shams University Maternity Hospital in the emergency ward from January 2019 to September 2019. It included 106 women with singleton pregnancies, gestational age from 28 - 36 weeks with preterm premature rupture of membranes. This study is designed to assess the efficacy of the amniotic fluid lamellar body counting (LBC) from a vaginal pool in predicting fetal lung maturity in women with preterm premature rupture of membranes. Results: The current study revealed a highly significant increase in the lamellar body count in cases giving birth to neonates without RDS compared to that cases giving birth to neonates with RDS. Also, no statistically significant difference between LBC and age, parity and number of previous miscarriages in the mother was found. Gestational age at delivery was significantly lower among cases with respiratory distress. Steroid administration was significantly less frequent among cases with respiratory distress. However, lamellar bodies had high diagnostic performance in the prediction of respiratory distress. Conclusion: Lamellar body count (LBC) is an effective, safe, easy, and cost-effective method to assess fetal lung maturity (FLM). It does not need a highly equipped laboratory or specially trained personnel, it just needs the conventional blood count analyzer. Measurement of LBC is now replacing the conventional Lecithin/Sphyngomyelin L/S ratio. LBC cut-off value of ≤42.5 × 103/μL can be used safely to decide fetal lung maturity with sensitivity of 95.7% and specificity of 97.6%.

Comparison of Perinatal Outcomes in Late Preterm Spontaneous and Indicated Preterm Birth Neonates

Objective: We aimed to compare the perinatal outcomes in late preterm spontaneous and indicated birth neonates. Methods: We studied 289 late preterm births, classified as either aspontaneous late preterm birth (sLPTB) group (preterm labor with intact membranes and preterm premature rupture of membranes) or an indicated late preterm birth (iLPTB) group (hypertensive disorder in pregnancy, placental causes, and maternal diseases), according to the delivery indication. We then compared the maternal and neonatal characteristics and perinatal outcomes, including the Apgar score, admission to the neonatal intensive care unit (NICU) or special care nursery (SCN), duration of NICU stay, and the rate of composite morbidity (antibiotic use, hypoglycemia, hypocalcemia, hyperbilirubinemia requiring phototherapy, respiratory support, and respiratory distress syndrome). Results: A total of 198 neonates were in the sLPTB group and 91 were in the iLPTB group. In spite of greater gestational age at the time of delivery in the iLPTB group, the mean birth weight was lower than that in the sLPTB group. Additionally, the iLPTB group showed lower Apgar scores, and higher rates of NICU or SCN admission, respiratory support, and hypoglycemia, but there was no difference in the rate of composite morbidity between the two groups. Conclusion: iLPTB neonates had lower birth weights despite greater gestational age than those in the sLPTB group, but there was no difference in the rate of composite morbidity between the two groups.

Mental health impact on Black,Asian and Minority Ethnic populations with preterm birth:A systematic review and meta-analysis

BACKGROUND Preterm birth(PTB)is one of the main causes of neonatal deaths globally,with approximately 15million infants are born preterm.Women from the Black,Asian,and Minority Ethnic(BAME)populations maybe at higher risk of PTB,therefore,the mental health impact on mothers experiencing a PTB is particularly important,within the BAME populations.AIM To determine the prevalence of mental health conditions among BAME women with PTB as well as the methods of mental health assessments used to characterise the mental health outcomes.METHODS A systematic methodology was developed and published as a protocol in PROSPERO(CRD420-20210863).Multiple databases were used to extract relevant data.I2 and Egger's tests were used to detect the heterogeneity and publication bias.A trim and fill method was used to demonstrate the influence of publication bias and the credibility of conclusions.RESULTS Thirty-nine studies met the eligibility criteria from a possible 3526.The prevalence rates of depression among PTB-BAME mothers were significantly higher than full-term mothers with a standardized mean difference of 1.5 and a 95%confidence interval(CI)29%-74%.The subgroup analysis indicated depressive symptoms to be time sensitive.Women within the very PTB category demonstrated a significantly higher prevalence of depression than those categorised as non-very PTB.The prevalence rates of anxiety and stress among PTB-BAME mothers were significantly higher than in full-term mothers(odds ratio of 88%and 60%with a CI of 42%-149%and 24%-106%,respectively).CONCLUSION BAME women with PTB suffer with mental health conditions.Many studies did not report on specific mental health outcomes for BAME populations.Therefore,the impact of PTB is not accurately represented in this population,and thus could negatively influence the quality of maternity services they receive.

Maternal and Neonatal Factors Associated with Mortality of Preterm Babies Admitted in Newborn Unit of Kenyatta National Hospital, Kenya

Background: Preterm birth is a primary cause of neonatal morbidity and mortality especially in low-income countries. Although understanding the preventable factors of neonatal deaths in preterm infants is required for timely interventions, data on those factors is lacking in Kenya. We attempted to determine mortality and its associated factors in preterm babies in Kenya. Methods and Materials: A hospital-based, prospective study was implemented from July 2019 to October 2019 involving 163 preterm neonates and their mothers admitted at Kenyatta National Hospital. A systematic random sampling method was used to recruit the study participants. Data on mortality and the associated factors in preterm neonates were collected using a pretested questionnaire for mothers and neonatal medical records. Data was analyzed using descriptive and inferential statistics. Results: The mortality rate was 18.4%. Of the neonates who died, respiratory distress syndrome (63.3%) and neonatal sepsis (20.0%) were documented as the primary causes. Neonates born of single mother (AOR = 8.006, 95% CI 2.267 to 28.272, p = 0.001), unemployed (6.960, 1.059 - 45.757, p = 0.043), self-employed (4.040, 1.067 - 15.302, p = 0.040), anemic (7.465, 2.530 - 22.023, p < 0.001) and with history of bleeding during pregnancy were more likely to have died. The neonates born before 28 weeks of gestation (126.188, 14.554 - 1094.060, p < 0.001), those who did not cry immediately at birth (54.271, 5.970 - 493.395, p < 0.001) and the resuscitated at birth (54.406, 6.807 - 434.851, p < 0.001) were likely to die. Conclusion: High mortality rates of preterm neonates are attributed to both maternal and neonatal factors. Focused antenatal care should aim at early identification of high-risk mothers for early management of bleeding during pregnancy, close monitoring of nutritional status for mothers and health education.

Correlation between Endocervical Length in the First Trimester and Spontaneous Preterm Delivery

Introduction: Prematurity is a public health problem in Brazil, with 12% of deliveries occurring before 37 weeks of gestation. The measurement of the cervix in the second trimester is already established as a method of screening for prematurity and some studies point out advantages to start this screening in the first trimester. Objective: To define the correlation between the length of the endocervix by transvaginal ultrasound in the first trimester (11 to 14 weeks) with spontaneous early deliveries. Method: A prospective and observational study realized in a suplementar and private ultrasound clinic and hospital of Porto Alegre, Brazil between 2019-2020. Ultrasound screening of cervix was performed in singleton pregnancies in first and second trimester of pregnancy and correlated with age of delivery. Results: 142 pregnant women were studied, 80% were in the first pregnancy. The average age was 33.8 years. The rate of prematurity was 18% before 37 weeks and 4% before 34 weeks. The average of cervix measured in the first and second trimesters in deliveries before 34 weeks was 32.7 mm and 29.3 mm, respectively. In term deliveries the median cervical length was 38.8 mm and 37.8 mm, respectively. When analyzing the measurements of the cervix in the second trimester, the cervix was smaller (p = 0.008) among deliveries below 34 weeks (29 mm) than deliveries after 37 weeks. No statistically related differences were found between preterm birth and first trimester cervix measurements. Conclusions: In this study, we did not observe a statistically significant relationship between first trimester cervix measurement and prematurity. More studies are needed to evaluate this finding. However, the measurement of the cervix in the second trimester is different from that found in the literature. This suggests a possible new cut-off point that increases the sensitivity of transvaginal ultrasound as a method of preventing prematurity.

A Time Series Analysis of Outdoor Air Pollution and Preterm Birth in Shanghai, China

Objective To investigate the relation between air pollution exposure and preterm birth in Shanghai, China. Methods We examined the effect of ambient air pollution on preterm birth using time-series approach in Shanghai in 2004. This method can eliminate potential confounding by individual risk factors that do not change over a short period of time. Daily numbers of preterm births were obtained from the live birth database maintained by Shanghai Municipal Center of Disease Control and Prevention. We used the generalized additive model （GAM） with penalized splines to analyze the relation between preterm birth, air pollution, and covariates. Results We observed a significant effect of outdoor air pollution only with 8-week exposure before preterm births. An increase of 10 μg/m^3 of 8-week average PM10, SO2, NO2, and O3 corresponded to 4.42% （95%CI 1.60%, 7.25%）, 11.89% （95%CI 6.69%, 17.09%）, 5.43% （95%CI 1.78%, 9.08%）, and 4.63% （95%CI 0.35%, 8.91%） increase of preterm birth. We did not find any significant acute effect of outdoor air pollution on preterm birth in the week before birth. Conclusion Ambient air pollution may contribute to the risk of preterm birth in Shanghai. Our analyses also strengthen the rationale for further limiting air pollution level in the city.

Early Intratracheal Administration of Corticosteroid and Pulmonary Surfactant for Preventing Bronchopulmonary Dysplasia in Preterm Infants with Neonatal Respiratory Distress Syndrome: A Meta-analysis

There is uncertain result with regard to the use of inhalation or instillation steroids to prevent bronchopulmonary dysplasia in preterm infants. This meta-analysis was designed to evaluate the efficacy and safety of early airway administration (within 2 days after birth) of corticosteroids and pulmonary surfactant (PS) for preventing bronchopulmonary dysplasia (BPD) in premature infants with neonatal respiratory distress syndrome (NRDS). The related studies were retrieved in PubMed, EMBASE, the Cochrane Library, Clinical Trial, CNKI, Wanfang and VIP Database from inception to August 2018. Two reviewers independently screened the studies to ensure that all patients with diagnosis of NRDS were enrolled to studies within 1 day after birth, assessed the quality of included studies by GRADEpro system and extracted the data for review. The meta-analysis was performed by RevMan 5.2 software. A subgroup analysis about inhaled corticosteroid (ICS) delivery method was made between ICS inhalation subgroup [inhalation of ICS by nebulizer or metered dose inhaler (MDI)] and ICS intratracheal instillation subgroup (PS used as a vehicle). Eight randomized controlled trials were enrolled in the meta-analysis, 5 trials of which stated the randomized method, grouping and blinded method, and the follow-up procedures were reported. GRADEpro system showed high quality of 4 trials (5 articles), and the rest 4 trials had moderate quality. Meta-analysis showed that the incidence of BPD was decreased in ICS group, the relative risk (RR) was 0.56 (95% CI: 0.42-0.76), and similar trends were found in ICS inhalation subgroup and ICS intratracheal instillation subgroup, with the corresponding RR being 0.58 (95% CI: 0.41-0.82) and 0.47 (95% CI: 0.24-0.95) respectively. ICS could also significantly reduce the mortality risk as compared with placebo control group (RR: 0.67;95% CI: 0.45-0.99), with RR of ICS inhalation subgroup and ICS intratracheal instillation subgroup being 0.81 (95% CI: 0.34-1.94) and 0.64 (95% CI: 0.41-0.99) respectively. Moreover, the percentage of infants using PS more than one time was lower in ICS group than in the placebo control group, with the RR and 95% CI being 0.55 (95% CI: 0.45-0.67), and that in ICS intratracheal instillation subgroup lower than in ICS inhalation subgroup (RR: 0.56;95% CI: 0.45-0.69, and RR: 0.35;95% CI:0.08-1.52 respectively). There was no significant difference in the incidence of infection or retinopathy of prematurity and neuro-motor system impairment between ICS group and placebo control group, with the corresponding RR being 0.95 (95% CI:0.59-1.52), 0.92 (95% CI: 0.62-1.38) and 1.13 (95% CI: 0.92-1.39), respectively. It was concluded that early administration of ICS and PS is an effective and safe option for preterm infants with NRDS in preventing BPD and reducing mortality, decreasing the additional PS usage, especially for the ICS intratracheal instillation subgroup. Furthermore, the appropriate dose and duration of ICS, combined use of inhalation or instillation of ICS with PS and the long-term safety of airway administration of corticosteroids need to be assessed in large trials.

Effects of Different Surfactant Administrations on Cerebral Autoregulation in Preterm Infants with Respiratory Distress Syndrome

To treat respiratory distress syndrome,surfactant is currently delivered via less invasive surfactant administration（LISA） or INtubation SURfactant Extubation（INSURE）.The aim of this study was to compare the effect of the two delivery methods of surfactant on cerebral autoregulation.Near infrared spectroscopy monitoring was carried out to detect cerebral oxygen saturation（Sc O2）,and the mean arterial blood pressure（MABP） was simultaneously recorded.Of 44 preterm infants included,the surfactant was administrated to 22 via LISA and 22 via INSURE.The clinical characteristics,treatments and outcomes of the infants showed no significant differences between the two groups.The correlation coefficient of Sc O2 and MABP（rSc O2-MABP） 5 min before administration was similar in the two groups.During surfactant administration,rSc O2-MABP increased in both groups（0.44±0.10 to 0.54±0.12 in LISA,0.45±0.11 to 0.69±0.09 in INSURE）.In the first and second 5 min after instillation,rSc O2-MABP was not significantly different from baseline in the LISA group,but increased in the first 5 min after instillation（0.59±0.13,P=0.000 compared with the baseline in the same group） and recovered in the second 5 min after instillation（0.48±0.10,P=0.321） in the INSURE group.There were significant differences in the change rates of rSc O2-MABP between the two groups during and after surfactant administration.Our results suggest that cerebral autoregulation may be affected transiently by surfactant administration.The effect duration of LISA is shorter than that of INSURE（〈5 min in LISA vs.5–10 min in INSURE）.

Reliability and validity of the Chinese version of the Readiness for Hospital Discharge Scale-Parent Form in parents of preterm infants

Background: The Readiness for Hospital Discharge Scale (RHDS)-Parent Form shows satisfactory reli-ability and validity to assess the readiness of parents to take care of their children discharged from hospitals in Western countries. However, the reliability and validity of this instrument has not been evaluated in Chinese populations.Objectives: Evaluate the psychometric features of the RHDS-Parent Form among Chinese parents of preterm infants. Methods: The RHDS-Parent Form was translated into a Chinese version following an international in-strument translation guideline. A total of 168 parents with preterm infants were recruited from the neonatal intensive care units of two tertiary-level hospitals in China. The internal consistency of this measure was assessed using the Cronbach's a coefficient;confirmatory factor analysis was conducted to evaluate the construct validity;and Pearson correlation coefficient was used to report the convergent validity. Results: The Chinese version of RHDS (C-RHDS)-Parent Form included 22 items with 4 subscales, ac-counting for 56.71% of the total variance. The C-RHDS-Parent Form and its subscales showed good reliability (Cronbach's a values 0.78-0.92). This measure and its subscales showed positive correlations with the score of Quality of Discharge Teaching Scale. Conclusion: The factor structure of C-RHDS-Parent Form is partially consistent with the original English version. Future studies are needed to explore the factors within this measure before it is widely used in Chinese clinical care settings.

Ethnic Differences in Preterm Birth Risks for Pregnant Women with Thyroid Dysfunction or Autoimmunity:A Meta-analysis

Objective Abnormal maternal thyroid function is associated with preterm birth.However,this association stays dubious in relevant individual studies for ethnic difference reasons and lack of direct supporting data.This study aimed to evaluate the relationship between preterm birth and thyroid dysfunction or autoimmunity based on ethnic differences.Methods Relevant studies were identified through searches of MEDLINE,Excerpta Medica,Wan Fang,China Biological Medicine disc,and China National Knowledge Infrastructure from inception to June 15,2016.Original articles in which an incidence or prevalence of thyroid dysfunction or autoimmunity before second trimester of pregnancy could be extracted were included.Results Thirty-two unique studies were included for the final meta-analysis.Patients involved were divided into two groups：Group 1（G1） and Group 2（G2） comprising of Asian and Caucasian populations,respectively.Positive thyroid antibodies were associated with the occurrence of preterm birth in both G1 [odds ratio（OR）：3.62,95% confidence interval（CI）：2.83-4.65] and G2（OR：1.35,95% CI：1.17-1.56）;hypothyroidism,only in G2（OR：1.20,CI：1.09-1.33）;and subclinical hypothyroidism or hypothyroxinemia,in neither group.Conclusion Thyroid autoimmunity may be a more favorable factor leading to preterm birth among pregnant women of different ethnicities,compared with thyroid dysfunction.

Caffeine therapy in preterm infants

Caffeine is the most commonly used medication for treatment of apnea of prematurity. Its effect has been well established in reducing the frequency of apnea, intermittent hypoxemia, and extubation failure in mechanically ventilated preterm infants. Evidence for additional short-term benefits on reducing the incidence of bronchopulmonary dysplasia and patent ductus arteriosus has also been suggested. Controversies existamong various neonatal intensive care units in terms of drug efficacy compared to other methylxanthines, dosage regimen, time of initiation, duration of therapy, drug safety and value of therapeutic drug monitoring. In the current review, we will summarize the available evidence for the best practice in using caffeine therapy in preterm infants.