Epidemiology of late preterm (near-term) births

A randomized controlled trial of restricted versus standard fluid management in late preterm and term infants with transient tachypnea of the newborn

BACKGROUND

Transient tachypnea of the newborn(TTNB) is the most common respiratory morbidity in late preterm and term babies and is pathophysiologically related to delayed lung fluid clearance after birth. Mimicking low physiological fluid intake in the initial period of life may accelerate the recovery from TTNB. In a randomized controlled trial, we compared the roles of restricted versus standard fluid management in babies with TTNB requiring respiratory support.

METHODS

This parallel group,non-blinded, stratified randomized controlled trial was conducted in a level III neonatal unit of eastern India. Late preterm and term babies with TTNB requiring continuous positive airway pressure (CPAP) were randomly allocated to standard and restricted fluid arms for the first 72 hours (hrs). Primary outcome was CPAP duration.

RESULTS

In total, 100 babies were enrolled in this study with 50 babies in each arm. CPAP duration was significantly less in the restricted arm (48[42, 54] hrs vs 54[48,72] hrs, p = 0.002). However, no difference was observed in the incidence of CPAP failure between the two arms. In the subgroup analysis, the benefit of reduced CPAP duration persisted in late preterm but not in term infants. However, the effect was not significant in the late preterm babies exposed to antenatal steroid.

CONCLUSION

This trial demonstrated the safety and effectiveness of restrictive fluid strategy in reducing CPAP duration in late preterm and term babies with TTNB. Late preterm babies, especially those not exposed to antenatal steroid were the most benefitted by this strategy.

Morbidity in Late Preterm Birth: A Retrospective Cohort Study Assessing the Role of Immaturity versus Antecedent Factors

INTRODUCTION

Late preterm infants (LPIs) are infants born between 340/7 and 366/7 weeks gestation. Morbidities in these infants are commonly considered a result of prematurity; however, some research has suggested immaturity may not be the sole cause of morbidities. We hypothesize that antecedents leading to late preterm birth are associated with different patterns of morbidities and that morbidities are the result of gestational age superimposed by the underlying etiologies of preterm delivery.

METHODS

This is a retrospective cohort study of late preterm neonates born at a single tertiary care center. We examined neonatal morbidities including apnea of prematurity, hyperbilirubinemia, hypoglycemia, and the requirement for continuous positive airway pressure (CPAP). Multivariable logistic regression analysis was performed to estimate the risk of each morbidity associated with 3 categorized antecedents of delivery, that is, spontaneous preterm labor, preterm premature rupture of membranes (PPROM), and medically indicated birth. We calculated the predictive probability of each antecedent resulting in individual morbidity across gestational ages.

RESULTS

279 LPIs were included in the study. Decreasing gestational age was associated with significantly increased risk of apnea of prematurity, hyperbilirubinemia, and requirement of CPAP. In our cohort, the risk of hypoglycemia increased with gestational age, with the greatest incidence at 360-6 weeks. There was no significant association of risk of selected morbidities and the antecedents of late preterm delivery, with or without adjustment for gestational age, multiple gestation, small for gestational age (SGA), antenatal steroids, and delivery method.

DISCUSSION AND CONCLUSION

This study found no difference in morbidity risk related to 3 common antecedents of preterm birth in LPIs. Our research suggests that immaturity is the primary factor in determining adverse outcomes, intensified by factors resulting in prematurity.

[Teenage pregnancy and prematurity in Brazil, 2011-2012]

The study aims to evaluate the association between teenage pregnancy and prematurity. The data are from the Birth in Brazil study, a national survey consisting of 23,894 postpartum women and their newborn infants. The information was obtained from interviews with the mothers during their postpartum hospital stay. A matching method was established, based on propensity scores, to deal with differences between the groups due to the non-experimental design of the Birth in Brazil study. The study outcome was gestational age, considering all the premature births (gestational age < 37 weeks) and term births (gestational age 37 weeks to 41 weeks and 6 days). The study revealed social, economic, and maternal care disparities between the women according to age bracket. The highest proportions of teenage mothers were in the least developed regions of Brazil (North and Northeast) and in the poorest economic classes. After matching for socioeconomic and obstetric care characteristics, the highest odds of spontaneous prematurity were seen in younger adolescents compared to older adolescents (OR = 1.49; 95%CI: 1.07-2.06), and young adults (OR = 2.38; 95%CI: 1.82-3.12). Prematurity is still an issue in the field of maternal and child health, and the association with teenage pregnancy identified in this study is worrisome, especially because younger adolescent mothers were associated with higher odds of spontaneous prematurity.

[Visualization of unstructured personal narratives of perterm birth using text network analysis]

PURPOSE

This study aimed to identify the components of preterm birth (PTB) through women's personal narratives and to visualize clinical symptom expressions (CSEs).

METHODS

The participants were 11 women who gave birth before 37 weeks of gestational age. Personal narratives were collected by interactive unstructured storytelling via individual interviews, from August 8 to December 4, 2019 after receiving approval of the Institutional Review Board. The textual data were converted to PDF and analyzed using the MAXQDA program (VERBI Software).

RESULTS

The participants' mean age was 34.6 (±2.98) years, and five participants had a spontaneous vaginal birth. The following nine components of PTB were identified: obstetric condition, emotional condition, physical condition, medical condition, hospital environment, life-related stress, pregnancy-related stress, spousal support, and informational support. The top three codes were preterm labor, personal characteristics, and premature rupture of membrane, and the codes found for more than half of the participants were short cervix, fear of PTB, concern about fetal well-being, sleep difficulty, insufficient spousal and informational support, and physical difficulties. The top six CSEs were stress, hydramnios, false labor, concern about fetal wellbeing, true labor pain, and uterine contraction. "Stress" was ranked first in terms of frequency and "uterine contraction" had individual attributes.

CONCLUSION

The text network analysis of narratives from women who gave birth preterm yielded nine PTB components and six CSEs. These nine components should be included for developing a reliable and valid scale for PTB risk and stress. The CSEs can be applied for assessing preterm labor, as well as considered as strategies for students in women's health nursing practicum.

Factors Associated With Late Prematurity in the University Hospital of Valle Cali, Colombia During 2013-2014

Introduction: The birth rate of late premature babies has been increasing in recent years, composing now 75% of all premature births. This growing trend can be explained by different demographic transformations such as an increase in the demand for infertility treatments, older maternal age and the higher incidence of multiple pregnancies, cesarean sections, and labor induction. These premature babies contribute 30% to the global neonatal mortality rate. Objective: To identify the factors associated with late prematurity at the Hospital Universitario del Valle during the years 2013-2014. Methodology: Case and control design, 424 patients, 212 cases and 212 controls participated. Cases were defined as newborns with gestational age between 34 and 36 weeks and 6 days old. For the analysis, logistic regression models were developed and association forces (OR) were determined. Results: A univariate analysis shows that the proportion of teenage pregnant women corresponds to 22.64%. Bivariate analysis shows the maternal morbidity due to hypertensive disorders was 1.6 times higher (95% CI 1.06-2.63), the obstetric alterations in 2.9 times (CI of 95% 1.56-5.44), late preterm infants require more oxygen support 3.26 times (95% CI 1.76-6.03). After adjusting the model, it was found that late premature infants have a 3-fold probability of requiring some resuscitation maneuver (ORa 3.23 95% CI 2.09-4.99), birth is higher by cesarean section by 4.17 times (ORa 4.17 IC 95% 2.50-6.98), maternal morbidity was higher in 1.37 times (ORa 1.37 95% CI 1.14-1.65). The morbidity of the newborn was greater, close to the statistical significance for late premature infants in 1.26 times (ORa 1.26 95% CI 0.97-1.64). Conclusions: Late premature births in this study show a higher probability of developing morbidity, have a greater opportunity to be born by cesarean section, are products of mothers with morbidity (specifically hypertensive disorders), and require further resuscitation with a need of early obstetric intervention.

Feeding the Late and Moderately Preterm Infant: A Position Paper of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition Committee on Nutrition

Nutritional guidelines and requirements for late or moderately preterm (LMPT) infants are notably absent, although they represent the largest population of preterm infants. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Committee on Nutrition (CoN) performed a review of the literature with the aim to provide guidance on how to feed infants born LMPT, and identify gaps in the literature and research priorities.Only limited data from controlled trials are available. Late preterm infants have unique, often unrecognized, vulnerabilities that predispose them to high rates of nutritionally related morbidity and hospital readmissions. They frequently have feeding difficulties that delay hospital discharge, and poorer rates of breastfeeding initiation and duration compared with term infants. This review also identified that moderately preterm infants frequently exhibit postnatal growth restriction.The ESPGHAN CoN strongly endorses breast milk as the preferred method of feeding LMPT infants and also emphasizes that mothers of LMPT infants should receive qualified, extended lactation support, and frequent follow-up. Individualized feeding plans should be promoted. Hospital discharge should be delayed until LMPT infants have a safe discharge plan that takes into account local situation and resources.In the LMPT population, the need for active nutritional support increases with lower gestational ages. There may be a role for enhanced nutritional support including the use of human milk fortifier, enriched formula, parenteral nutrition, and/or additional supplements, depending on factors, such as gestational age, birth weight, and significant comorbidities. Further research is needed to assess the benefits (improved nutrient intakes) versus risks (interruption of breast-feeding) of providing nutrient-enrichment to the LMPT infant.

Postnatal length and weight growth velocities according to Fenton reference and their associated perinatal factors in healthy late preterm infants during birth to term-corrected age: an observational study

Background

Optimum early postnatal growth is critical for early and later health of preterm infants. Postnatal length and weight growth velocities and their associated perinatal factors in healthy late preterm infants without restriction of neonatal complications and nutritional problems have not been widely studied.

Methods

As part of ongoing longitudinal follow-up study of growth and development of preterm infants in Shandong Qianfoshan Hospital in China, 599 healthy late preterm infants without neonatal complications and nutritional problems were sampled from 795 preterm infants born in January 2014 to April 2017. Perinatal factors, growth parameters, growth velocities(ΔLengthZ and ΔWeightZ: Z-score changes of length and weight) during birth and term-corrected age were documented. Associated variables of growth velocities were analyzed by bivariate and multivariate regression analyses. Adjusted ΔLengthZ and ΔWeightZ were compared between/among subgroups of associated variables using analysis of covariance. Catch-up growth were defined as ΔLengthZ or ΔWeightZ > 0.67.

Results

The mean ΔLengthZ and ΔWeightZ were 0.28, 0.65, respectively. Catch-up growth of length and weight was ubiquitous(30.7, 46.2%, respectively). Faster length growth velocity was associated with male, larger postmenstrual age(PMA) at birth, younger mother and larger PMA at visit; Faster weight growth velocity was associated with male, unfavorable intrauterine growth status defined by birth weight percentile(Small-for-Gestational-Age(<P10), Appropriate-for-Gestational-Age(P10–90), Large-for-Gestational-Age(>P90)), twin and larger PMA at visit. When adjusted for associated co-variables, weight catch-up growth existed in subgroups of 36 weeks PMA at birth, male, twin and SGA, while AGA almost reached this standard with mean adjusted ΔWeightZ as 0.66. Although none of these subgroups got length catch-up growth standard, infants of 36 weeks PMA at birth had statistically rapider length growth velocity than 34 and 35 weeks PMA at birth subgroups(mean adjusted ΔLengthZs of 34, 35 and 36 weeks subgroups: 0.10, 0.22, 0.38, respectively).

Conclusions

Postnatal length and weight growth velocities of healthy late preterm infants from birth to term-corrected age were much superior than that of Fenton reference, especially for weight, with ubiquitous catch-up growth. Different associated factors for length and weight growth signified the necessity of constructing more detailed growth standards by specific stratification for associated factors.

The fetal fibronectin test: 25 years after its development, what is the evidence regarding its clinical utility? A systematic review and meta-analysis

Background: The identification of women at risk for preterm birth should allow interventions which could improve neonatal outcome. Fetal fibronectin, a glycoprotein which acts normally as glue between decidua and amniotic membranes could be a good marker of impending labour when its concentration in cervicovaginal secretions between 22 and 36 weeks of gestation is ≥50 ng/mL. Many authors worldwide have tested this marker with many different methodologies and clinical settings, but conclusions about its clinical use are mixed. It is time for a comprehensive update through a systematic review and meta-analysis.Methods: We searched PubMed, Cochrane Library, and Embase, supplemented by manual search of bibliographies of known primary and review articles, international conference papers, and contact with experts from 1-1990 to 2-2018. We have selected all type of studies involving fetal fibronectin test accuracy for preterm delivery. Two authors independently extracted data about study characteristics and quality from identified publications. Contingency tables were constructed. Reference standards were preterm delivery before 37, 36, 35, 34, and 32 weeks, within 28, 21, 14, or 7 d and within 48 h. Data were pooled to produce summary likelihood ratios for positive and negative tests results.Results: One hundred and ninety-three primary studies were identified allowing analysis of 53 subgroups. In all settings, none of the summary likelihood ratios were >10 or <0.1, thus indicating moderate prediction, particularly in asymptomatic women and in multiple gestations.Conclusions: The fetal fibronectin test should not be used as a screening test for asymptomatic women. For high-risk asymptomatic women, and especially for women with multiple pregnancies, the performance of the fetal fibronectin test was also too low to be clinically relevant. Consensual use as a diagnostic tool for women with suspected preterm labor, the best use policy probably still depends on local contingencies, future cost-effectiveness analysis, and comparison with other more recent available biochemical markers.

Identification of preterm birth in women with threatened preterm labour between 34 and 37 weeks of gestation

The aim of this study was to assess whether serum markers would be useful as a new predictor of preterm birth in patients with spontaneous, late preterm labour. Patients diagnosed with late preterm labour were divided into preterm delivery (229 patients) and term delivery (178 patients) groups. The two groups were compared in terms of clinical characteristics and levels of serum markers (leukocyte subtypes, platelet, C-reactive protein [CRP], neutrophil to lymphocyte ratio [NLR] and platelet to lymphocyte ratio [PLR]), which were obtained at admission. The levels of leukocyte (p < .001), neutrophil (p < .001), CRP (p = .001), NLR (p < .001) and PLR (p = .003) were significantly higher, whereas lymphocytes (p = .012) were significantly lower in the preterm delivery group, compared to the term delivery group. On multivariate regression analysis, NLR positive was the most powerful predictive variable (OR = 1.41; 95%CI: 1.32-1.51; p = .005). NLR had the highest area under curve (0.711; 95%CI 0.662-0.760) in predicting preterm birth and a NLR >6.2 had the highest sensitivity (65.1%) and specificity (62.5%). High NLR at admission is an independent predictor of preterm birth in patients with spontaneous, late preterm labour. Impact statement What is already known on this subject: Preterm birth accounts for 5-12% of all births, and is a major factor associated with perinatal morbidity and mortality worldwide. However, more than 70% of preterm births occur at late preterm between 34^0/7 and 36^6/7 weeks of gestation. The central role of systemic and subclinical infections in preterm labour is well documented. Intrauterine infection leading to delivery can be measured by using a variety of laboratory parameters. What do the results of this study add: Neutrophil to lymphocyte ratio is an inexpensive, easily interpretable and promising haematologic parameter that is widely available. This study explored the association of high neutrophil to lymphocyte ratio with the risk of preterm birth in women with preterm labour between 34 and 37 weeks of gestation. What are the implications of these findings for clinical practice and/or further research: Neutrophil to lymphocyte ratio could be used in combination with existing markers to improve detection rates of preterm birth. Concomitant use of markers could be more powerful than measuring any of the individual markers alone.

Avoiding late preterm deliveries to reduce neonatal complications: an 11-year cohort study

Background

Late preterm (LPT) newborns, defined as those born between 34 0/7 and 36 6/7 gestational weeks, have higher short- and long-term morbidity and mortality than term infants (≥37 weeks). A categorization to justify a non-spontaneous LPT delivery has been proposed to distinguish evidence-based from non-evidence-based criteria. This study aims to describe rates and temporal trends of non-spontaneous LPT neonates delivered according to evidence-based or non-evidence-based criteria and to evaluate the number of avoidable LPT deliveries, including severe neonatal morbidity rates and associated risk factors.

Methods

Retrospective cohort study including all LPT neonates born at a Swiss university maternity unit between January 1, 2002 and December 31, 2012. Trends of LPT neonates and neonatal complications were assessed across time using Poisson regression and risk factors for neonatal complications by logistic regression.

Results

Among 40,609 singleton live births, 4223 (10.5%) were preterm and 2017 (4.9%) LPT. In the latter group, 26.2% were non-spontaneous (evidence-based: 12.0%; non-evidence-based: 14.2%). The most frequent indications for evidence-based non-spontaneous LPT delivery were severe preeclampsia (51.8%) and abnormal fetal tracing (24.7%). Indications for non-evidence-based non-spontaneous LPT deliveries were hemorrhage (36.2%) and mild preeclampsia (15.7%). LPT birth rates remained stable over time. The rate of neonatal complications after non-evidence-based LPT birth remained high over time (43.8% vs. 43.5% in 2002 and 2012, respectively; P = 0.645), whereas the annual proportion of neonatal complications overall showed a decreasing trend (from 38.0% in 2002 to 33.5% in 2012; P = 0.051).

Conclusions

LPT birth rates were stable over time, but neonatal complications remained high, particularly after non-evidence-indicated LPT birth. A total of 287 LPT births could have been potentially avoided if an evidence-based protocol for delivery indications had been used. Efforts should be made to avoid non-spontaneous LPT births in order to reduce neonatal complications.

Specialist antenatal clinics for women at high risk of preterm birth: a systematic review of qualitative and quantitative research

Background

Preterm birth (PTB) is the leading cause of perinatal morbidity and mortality. Women with previous prenatal loss are at higher risk of preterm birth. A specialist antenatal clinic is considered as one approach to improve maternity and pregnancy outcomes.

Methods

A systematic review of quantitative, qualitative and mixed method studies conducted on women at high risk of preterm birth (PTB). The review primary outcomes were to report on the specialist antenatal clinics effect in preventing or reducing preterm birth, perinatal mortality and morbidity and women’s perceptions and experiences of a specialist clinic whether compared or not compared with standard antenatal care. Other secondary maternal, infant and economic outcomes were also determined. A comprehensive search strategy was carried out in English within electronic databases as far back as 1980. The reviewers selected studies, assessed the quality, and extracted data independently. Results were summarized and tabulated.

Results

Eleven studies fully met the review inclusion criteria, ten were quantitative design studies and only one was a qualitative design study. No mixed method design study was included in the review. All were published after 1989, seven were conducted in the USA and four in the UK. Results from five good to low quality randomised controlled trials (RCTs), all conducted before 1990, did not illustrate the efficacy of the clinic in reducing preterm birth. Whereas results from more recent low quality cohort studies showed some positive neonatal outcomes. Themes from one good quality qualitative study reflected on the emotional and psychological need to reduce anxiety and stress of women referred to such a clinic. Women expressed their negative emotional responses at being labelled as high risk and positive responses to being assessed and treated in the clinic. Women also reported that their partners were struggling to cope emotionally.

Conclusions

Findings from this review were mixed. Evidence from cohort studies indicated a specialist clinic may be a means of predicting or preventing preterm birth. Testing this in a randomised controlled trial is desirable, though may be hard to achieve due to the growing focus of such clinics on managing women at high risk of preterm birth. Ongoing research has to recognize women’s experiences and perceptions of such a clinic. Further clarification of the optimal referral route and a clear and standardized management and cost economic evaluation plan are also required. Fathers support and experience of PTB clinics should also be included in further research.

Prevalence and risk factors related to preterm birth in Brazil

BACKGROUND

The rate of preterm birth has been increasing worldwide, including in Brazil. This constitutes a significant public health challenge because of the higher levels of morbidity and mortality and long-term health effects associated with preterm birth. This study describes and quantifies factors affecting spontaneous and provider-initiated preterm birth in Brazil.

METHODS

Data are from the 2011-2012 "Birth in Brazil" study, which used a national population-based sample of 23,940 women. We analyzed the variables following a three-level hierarchical methodology. For each level, we performed non-conditional multiple logistic regression for both spontaneous and provider-initiated preterm birth.

RESULTS

The rate of preterm birth was 11.5 %, (95 % confidence 10.3 % to 12.9 %) 60.7 % spontaneous - with spontaneous onset of labor or premature preterm rupture of membranes - and 39.3 % provider-initiated, with more than 90 % of the last group being pre-labor cesarean deliveries. Socio-demographic factors associated with spontaneous preterm birth were adolescent pregnancy, low total years of schooling, and inadequate prenatal care. Other risk factors were previous preterm birth (OR 3.74; 95 % CI 2.92-4.79), multiple pregnancy (OR 16.42; 95 % CI 10.56-25.53), abruptio placentae (OR 2.38; 95 % CI 1.27-4.47) and infections (OR 4.89; 95 % CI 1.72-13.88). In contrast, provider-initiated preterm birth was associated with private childbirth healthcare (OR 1.47; 95 % CI 1.09-1.97), advanced-age pregnancy (OR 1.27; 95 % CI 1.01-1.59), two or more prior cesarean deliveries (OR 1.64; 95 % CI 1.19-2.26), multiple pregnancy (OR 20.29; 95 % CI 12.58-32.72) and any maternal or fetal pathology (OR 6.84; 95 % CI 5.56-8.42).

CONCLUSION

The high proportion of provider-initiated preterm birth and its association with prior cesarean deliveries and all of the studied maternal/fetal pathologies suggest that a reduction of this type of prematurity may be possible. The association of spontaneous preterm birth with socially-disadvantaged groups reaffirms that the reduction of social and health inequalities should continue to be a national priority.

Risk factors associated with late preterm births in the underdeveloped region of China: A cohort study and systematic review

OBJECTIVE

To determine factors associated with late preterm births in an underdeveloped region of China, and search for relevant reports in other underdeveloped regions by a systematic review.

MATERIALS AND METHODS

Data of births occurring between January 2004 and December 2008 from eight hospitals in Western Sichuan Province, China, were analyzed. Late preterm birth was defined as delivery at 34-36 6/7 weeks' gestation. Medline, Cochrane Library, and Google Scholar were searched for studies which reported the risk factors of late preterm births in undeveloped regions until January 31, 2014.

RESULTS

During the study period there were 4711 late preterm births and 54,574 term births. The odds ratios (ORs) for a late preterm birth of mothers < 20 years and ≥ 35 years of age were 3.813 [95% confidence interval (CI): 3.256-4.465] and 1.872 (95% CI: 1.677-2.090), respectively, as compared with an age of 20-34.9 years. Mothers who received prenatal care were less likely (OR = 0.623, 95% CI: 0.582-0.667) and those with a multiple gestation were more likely (OR = 9.346, 95% CI: 7.813, 11.236) to have a late preterm birth. The systematic review found that the incidence of late preterm births ranged from 4.4% to 16%, and the most prominent risk factors were eclampsia, preeclampsia, placenta previa, placental abruption, and twin pregnancy.

CONCLUSION

A number of factors are associated with late preterm births, and the incidence in underdeveloped regions is high. The inconsistent results between our study and previous reports indicate more attention towards preventing late preterm births in undeveloped regions is needed.

Provider-Initiated Late Preterm Births in Brazil: Differences between Public and Private Health Services

BACKGROUND

A large proportion of the rise in prematurity worldwide is owing to late preterm births, which may be due to the expansion of obstetric interventions, especially pre-labour caesarean section. Late preterm births pose similar risks to overall prematurity, making this trend a concern. In this study, we describe factors associated with provider-initiated late preterm birth and verify differences in provider-initiated late preterm birth rates between public and private health services according to obstetric risk.

METHODS

This is a sub-analysis of a national population-based survey of postpartum women entitled "Birth in Brazil", performed between 2011 and 2012. We included 23,472 singleton live births. We performed non-conditional multiple logistic regressions assessing associated factors and analysing differences between public and private health services.

RESULTS

Provider-initiated births accounted for 38% of late preterm births; 32% in public health services and 61% in private health services. They were associated with previous preterm birth(s) and maternal pathologies for women receiving both public and private services and with maternal age ≥35 years for women receiving public services. Women receiving private health services had higher rates of provider-initiated late preterm birth (rate of 4.8%) when compared to the ones receiving public services (rate of 2.4%), regardless of obstetric risk-adjusted OR of 2.3 (CI 1.5-3.6) for women of low obstetric risk and adjusted OR of 1.6 (CI 1.1-2.3) for women of high obstetric risk.

CONCLUSION

The high rates of provider-initiated late preterm birth suggests a considerable potential for reduction, as such prematurity can be avoided, especially in women of low obstetric risk. To promote healthy births, we advise introducing policies with incentives for the adoption of new models of birth care.

Neonatal respiratory morbidity in late-preterm births in pregnancies with and without gestational diabetes mellitus

OBJECTIVE

To evaluate neonatal respiratory morbidity in infants born late-preterm to mothers with or without gestational diabetes mellitus (GDM).

METHODS

Analysis of a population-based cohort of all live-born singletons, born at 34 0/7 to 36 6/7 weeks to mothers with and without GDM, focusing on transient tachypnea of the newborn (TTN) and respiratory distress syndrome (RDS).

RESULTS

The study group comprised 363 (4.7%) singletons born to mothers with GDM and the controls were 7400 born to mothers without GDM. Mothers with GDM were older (31.4 ± 5.1 versus 29.5 ± 5.1 years, p < 0.001) and were more likely to be hypertensive (OR 1.5, 95% CI 1.1-2.1). Neonates of GDM mothers were heavier at birth (2769 ± 539 versus 2636 ± 473 g, p < 0.001). We found a similar incidence of RDS and TTN in both groups. The multiple regression analysis showed cesarean delivery and lower gestational age were independently associated with RDS and TTN.

CONCLUSION

GDM, per se, is not a major contributor to RDS in late pre-term infants. Rather, the combination of prematurity and cesarean birth act independently to increase the risk of respiratory morbidity.

Is prematurity a risk factor for developmental dysplasia of the hip? : a prospective study

The aim of this prospective study was to investigate prematurity as a risk factor for developmental dysplasia of the hip (DDH). The hips of 221 infants (88 female, 133 male, mean age 31.11 weeks; standard deviation (sd) 2.51) who were born in the 34th week of gestation or earlier, and those of 246 infants (118 female, 128 male, mean age 40.22 weeks; sd 0.36) who were born in the 40th week of gestation, none of whom had risk factors for DDH, were compared using physical examination and ultrasound according to the technique of Graf, within one week, after the correction of gestational age to the 40th week after birth or one week since birth, respectively. Both hips of all infants were included in the study. Ortolani's and Barlow's tests and restricted abduction were accepted as positive findings on examination. There was a statistically significant difference between pre- and full-term infants, according to the incidence of mature and immature hips (p < 0.001). The difference in the proportion of infants with an α angle < 60° between the two groups was statistically significant (p < 0.001). The incidence of pathological dysplasia (α angle < 50 º) was not significantly different in the two groups (p = 1.000). The Barlow sign was present in two (0.5%) pre-term infants and in 14 (2.8%) full-term infants. These results suggests that prematurity is not a predisposing factor for DDH.

Communication impairments in early term and late preterm children: a prospective cohort study following children to age 36 months

OBJECTIVE

To investigate the risk of communication impairments at age 18 and 36 months in children born early term (gestational weeks 37-38) and late preterm (gestational weeks 34-36).

STUDY DESIGN

A total of 39 423 children and their mothers participated in the Norwegian Mother and Child Cohort Study. The sample included 7109 children (18%) born early term and 1673 (4.2%) born late preterm. Information on gestational age and prenatal and postnatal risk factors was obtained from the Medical Birth Registry of Norway. Information on communication impairments was assessed using standardized questionnaires filled out by the mothers. Stepwise logistic regression analysis was applied to explore the associations between early term/late preterm birth and communication impairments at age 18 and 36 months.

RESULTS

Compared with children born at term, children born early term and late preterm had an increased risk of communication impairments at age 18 and 36 months. In early term, the aOR was 1.27 (95% CI, 1.12-1.44) at 18 months for communication impairments and 1.22 (95% CI, 1.07-1.39) at 36 months for expressive language impairments. In late preterm, the aOR was 1.74 (95% CI, 1.41-2.14) at 18 months and 1.37 (95% CI, 1.09-1.73) at 36 months.

CONCLUSION

Not only children born late preterm, but also those born early term, are at increased risk for communication impairments. Given the large number of children potentially affected, this may result in significant health care costs.

Disparities in mortality rates among US infants born late preterm or early term, 2003-2005

The purpose of this study was to identify disparities in neonatal, post-neonatal, and overall infant mortality rates among infants born late preterm (34-36 weeks gestation) and early term (37-38 weeks gestation) by race/ethnicity, maternal age, and plurality. In analyses of 2003-2005 data from US period linked birth/infant death datasets, we compared infant mortality rates by race/ethnicity, maternal age, and plurality among infants born late preterm or early term and also determined the leading causes of death among these infants. Among infants born late preterm, infants born to American Indian/Alaskan Native, non-Hispanic black, or teenage mothers had the highest infant mortality rates per 1,000 live births (14.85, 9.90, and 11.88 respectively). Among infants born early term, corresponding mortality rates were 5.69, 4.49, and 4.82, respectively. Among infants born late preterm, singletons had a higher infant mortality rate than twins (8.59 vs. 5.62), whereas among infants born early term, the rate was higher among twins (3.67 vs. 3.15). Congenital malformations and sudden infant death syndrome were the leading causes of death among both late preterm and early term infants. Infant mortality rates among infants born late preterm or early term varied substantially by maternal race/ethnicity, maternal age, and plurality. Information about these disparities may help in the development of clinical practice and prevention strategies targeting infants at highest risk.

Asthma during pregnancy in a population-based study--pregnancy complications and adverse perinatal outcomes

Background

Asthma is one of the most common chronic diseases, and prevalence, severity and medication may have an effect on pregnancy. We examined maternal asthma, asthma severity and control in relation to pregnancy complications, labour characteristics and perinatal outcomes.

Methods

We retrieved data on all singleton births from July 1, 2006 to December 31, 2009, and prescribed drugs and physician-diagnosed asthma on the same women from multiple Swedish registers. The associations were estimated with logistic regression.

Results

In total, 266 045 women gave birth to 284 214 singletons during the study period. Maternal asthma was noted in 26 586 (9.4%) pregnancies. There was an association between maternal asthma and increased risks of pregnancy complications including preeclampsia or eclampsia (adjusted OR 1.15; 95% CI 1.06–1.24) and premature contractions (adj OR 1.52; 95% CI 1.29–1.80). There was also a significant association between maternal asthma and emergency caesarean section (adj OR 1.29; 95% CI 1.23–1.34), low birth weight, and small for gestational age (adj OR 1.23; 95% CI 1.13–1.33). The risk of adverse outcomes such as low birth weight increased with increasing asthma severity. For women with uncontrolled compared to those with controlled asthma the results for adverse outcomes were inconsistent displaying both increased and decreased OR for some outcomes.

Conclusion

Maternal asthma is associated with a number of serious pregnancy complications and adverse perinatal outcomes. Some complications are even more likely with increased asthma severity. With greater awareness and proper management, outcomes would most likely improve.

Factor affecting length of stay in late preterm infants: an US national database study

OBJECTIVES

Late preterm infants are the fastest growing segment of the premature infant population in the United States. However, it is not known if demographic and clinical factors can impact the length of hospital stay (LOS) in this population. The objectives of this study are to determine the following: (a) factors associated with a LOS > 3 d and (b) whether there is any difference in risks between infants born at 33-34 versus 35-36 weeks.

METHODS

Utilizing the Nationwide Inpatient Sample Database, a de-identified dataset produced by the Healthcare Cost and Utilization Project, analysis of 81 913 infants born at 33-36 weeks from 2007 to 2008 was conducted. LOS outcome was defined as ≤3 and >3 d. Bivariable and multivariable logistic regression was used to evaluate predictors of LOS among this population.

RESULTS

Only 42.7% of infants were discharged home within three days. Factors associated with a LOS > 3 d included gestational age of <35 weeks (RR = 1.63; CI: 1.58-1.68), birth weight of < 2500 g (RR = 1.36; CI: 1.33-1.39), male sex (RR = 1.06; CI: 1.05-1.07), delivery via C-section (RR = 1.46; CI: 1.41-1.51) and multiple gestation (RR = 1.08; 95% CI: 1.06-1.09). Other significant factors included race, birth region, primary insurance payer and clinical complications. In the adjusted interaction model, these variables have more impact on longer LOS in the 35-36 weeks group (p < 0.0001).

CONCLUSION

Birth region in addition to gestational age, birth weight, gender, mode of delivery, multiple gestation and primary insurance payer affect LOS in late preterm infants. These variables are more critical for the 35-36 week population.

Short-term respiratory outcomes in late preterm infants

Objective

To evaluate short-term respiratory outcomes in late preterm infants (LPI) compared with those of term infants (TI).

Methods

A retrospective study conducted in a single third level Italian centre (2005–2009) to analyse the incidence and risk factors of composite respiratory morbidity (CRM), the need for adjunctive therapies (surfactant therapy, inhaled nitric oxide, pleural drainage), the highest level of respiratory support (mechanical ventilation – MV, nasal continuous positive airway pressure – N-CPAP, nasal oxygen) and the duration of pressure support (hours in N-CPAP and/or MV).

Results

During the study period 14,515 infants were delivered. There were 856 (5.9%) LPI and 12,948 (89.2%) TI. CRM affected 105 LPI (12.4%), and 121 TI (0.9%), with an overall rate of 1.6%. Eighty-four LPI (9.8%) and 73 TI (0.56%) received respiratory support, of which 13 LPI (1.5%) and 16 TI (0.12%) were ventilated. The adjusted OR for developing CRM significantly increased from 3.3 (95% CI 2.0-5.5) at 37 weeks to 40.8 (95% CI 19.7-84.9%) at 34 weeks. The adjusted OR for the need of MV significantly increased from 3.4 (95% CI 1.2-10) at 37 weeks to 34.4 (95% CI 6.7-180.6%) at 34 weeks. Median duration of pressure support was significantly higher at 37 weeks (66.6 h vs 40.5 h). Twin pregnancies were related to a higher risk of CRM (OR 4.3, 95% CI 2.6-7.3), but not independent of gestational age (GA). Cesarean section (CS) was associated with higher risk of CRM independently of GA, but the OR was lower in CS with labour (2.2, 95% CI 1.4-3.4 vs 3.0, 95% CI 2.1-4.2).

Conclusions

In this single third level care study late preterm births, pulmonary diseases and supportive respiratory interventions were lower than previously documented. LPI are at a higher risk of developing pulmonary disease than TI. Infants born from elective cesarean sections, late preterm twins in particular and 37 weekers too might benefit from preventive intervention.

[Respiratory disorders among late-preterm infants in a neonatal intensive care unit]

INTRODUCTION

The rate of infants born at 34-36 weeks of gestation has increased over the last 20 years. These babies are at higher risk of morbidity, particularly respiratory, than full-term infants are. The purpose of this study was to describe the respiratory morbidity of late-preterm infants and identify risk factors.

PATIENTS AND METHODS

This was a descriptive, single-center study including 273 late-preterm infants born in a tertiary care hospital between July 2009 and December 2010.

RESULTS

Of the mothers who delivered, 53.9% had morbidity. The cesarean-section delivery rate before labor was 20.9%; the main indication was fetal growth restriction (34%). Sixty-four percent of newborns had morbidity during their hospitalization and 23.1% suffered from respiratory distress. Mechanical ventilation was needed in 4.4% of the infants. Respiratory distress was mainly caused by early-onset sepsis or transient tachypnea. Ten infants presented with respiratory distress syndrome, of whom seven received a surfactant. Neonatal respiratory distress risk factors were gestational age, sex, and prelabor cesarean section (P<0.05).

CONCLUSION

Late-preterm infants have an increased risk of respiratory disorders requiring ventilation. Elective cesarean should be limited if possible during this period.

A Genome-Wide Association Study of spontaneous preterm birth in a European population

Background: Preterm birth is defined as a birth prior to 37 completed weeks’ gestation. It affects more than 10% of all births worldwide, and is the leading cause of neonatal mortality in non-anomalous newborns. Even if the preterm newborn survives, there is an increased risk of lifelong morbidity. Despite the magnitude of this public health problem, the etiology of spontaneous preterm birth is not well understood. Previous studies suggest that genetics is an important contributing factor. We therefore employed a genome-wide association approach to explore possible fetal genetic variants that may be associated with spontaneous preterm birth.Methods: We obtained preterm birth phenotype and genotype data from the National Center for Biotechnology Information Genotypes and Phenotypes Database (study accession phs000103.v1.p1). This dataset contains participants collected by the Danish National Birth Cohort and includes 1000 preterm births and 1000 term births as controls. Whole genomes were genotyped on the Illumina Human660W-Quad_v1_A platform, which contains more than 500,000 markers. After data quality control, we performed genome-wide association studies for the 22 autosomal chromosomes.Results: No single nucleotide polymorphism reached genome-wide significance after Bonferroni correction for multiple testing.Conclusion: We found no evidence of genetic association with spontaneous preterm birth in this European population. Approaches that facilitate detection of both common and rare genetic variants, such as evaluation of high-risk pedigrees and genome sequencing, may be more successful in identifying genes associated with spontaneous preterm birth.

Late preterm infants: near term but still in a critical developmental time period

Late preterm (LP) infants are defined as those born at 34-0/7 to 36-6/7 weeks' gestational age. LP infants were previously referred to as near term infants. The change in terminology resulted from the understanding that these infants are not fully mature and that the last 6 weeks of gestation represent a critical period of growth and development of the fetal brain and lungs, and of other systems. There is accumulating evidence of higher risks for health complications in these infants, including serious morbidity and a threefold higher infant mortality rate compared with term infants. This information is of critical importance because of its scientific merits and practical implications. However, it warrants a critical and balanced review, given the apparent overall uncomplicated outcome for the majority of LP infants. Others reviewed the characteristics of LP infants that predispose them to a higher risk of morbidity at the neonatal period. This review focuses on the long-term neurodevelopmental and respiratory outcomes, with the main aim to suggest putative prenatal, neonatal, developmental, and environmental causes for these increased morbidities. It demonstrates parallelism in the trajectories of pulmonary and neurologic development and evolution as a model for fetal and neonatal maturation. These may suggest the critical developmental time period as the common pathway that leads to the outcomes. Disruption in this pathway with potential long-term consequences in both systems may occur if the intrauterine milieu is disturbed. Finally, the review addresses the practical implications on perinatal and neonatal care during infancy and childhood.

Características maternas em gestações com risco de prematuridade tardia

OBJETIVOS: avaliar as características maternas na prematuridade tardia. MÉTODOS: foi realizado um estudo do tipo corte transversal, com análise secundária das gestantes incluídas em um ensaio clínico randomizado realizado no Nordeste do Brasil, no período de 2008 a 2010, entre 34 e 36 semanas. Analisadas as variáveis maternas: idade, paridade, idade gestacional, antecedentes de prematuridade e condições clínicas associadas. A análise estatística foi realizada no programa Epi-Info 3.5.3. Foram construídas tabelas de distribuição de frequência para as variáveis categóricas e calculadas medidas de tendência central e de dispersão para as numéricas. Para determinação da associação entre a frequência das morbidades por estratos de idade gestacional, utilizou-se o teste qui-quadrado de associação. Considerou-se o nível de significância de 5%. RESULTADOS: foram analisadas 273 mulheres no IMIP com risco iminente de prematuridade tardia. A idade média foi 23,1 anos, 28,6% eram adolescentes e 53,8% primíparas. A idade gestacional média foi 35 semanas. Cerca de 12% tinham antecedentes de prematuridade. As condições associadas à prematuridade tardia foram: trabalho de parto prematuro (67%), ruptura prematura das membranas (39,6%), síndromes hipertensivas (25,3%), sem haver diferença da frequência por subgrupos de idade gestacional. CONCLUSÕES: trabalho de parto prematuro espontâneo, ruptura prematura das membranas e síndromes hipertensivas foram as condições clínicas mais frequentemente associadas com prematuridade tardia.

Chronic chorioamnionitis is the most common placental lesion in late preterm birth

OBJECTIVES

The pathogenesis of late preterm birth remains elusive for the mechanisms of disease responsible. Placental examination can often provide important clues for the pathogenesis of pregnancy complications. This study was conducted to determine placental pathologic findings according to the gestational age and the clinical circumstances of preterm birth.

STUDY DESIGN

Placental pathologic findings and obstetrical and neonatal outcomes were reviewed in a consecutive preterm birth cohort from a single tertiary center (N = 1206). Placentas of term births (N = 300) were used as normal controls.

RESULTS

Acute chorioamnionitis (22.7% vs. 16.7%), maternal vascular underperfusion (6.4% vs. 0.5%), and chronic chorioamnionitis (20.8% vs. 10.5%) were significantly more frequent in preterm births than in term births (P < 0.05, for each). Among preterm births, chronic chorioamnionitis was the most common pathology of late preterm birth (gestational age <37 and ≥34 weeks), while acute chorioamnionitis was the most common lesion of extremely preterm birth (gestational age <28 weeks). While the frequency of acute chorioamnionitis decreased with advancing gestation, that of chronic chorioamnionitis increased (P < 0.001, for each). The upward trend of the frequency of chronic chorioamnionitis was related to advancing gestation in both spontaneous and indicated preterm births (P < 0.001, for each).

CONCLUSIONS

Chronic chorioamnionitis is a common pathology of late preterm birth. It is suggested that chronic chorioamnionitis, a feature of maternal anti-fetal rejection, is an important etiology of preterm birth, especially of late preterm birth.

Effect of interleukin-6 polymorphism on risk of preterm birth within population strata: a meta-analysis

Background

Because of the role of inflammation in preterm birth (PTB), polymorphisms in and near the interleukin-6 gene (IL6) have been association study targets. Several previous studies have assessed the association between PTB and a single nucleotide polymorphism (SNP), rs1800795, located in the IL6 gene promoter region. Their results have been inconsistent and SNP frequencies have varied strikingly among different populations. We therefore conducted a meta-analysis with subgroup analysis by population strata to: (1) reduce the confounding effect of population structure, (2) increase sample size and statistical power, and (3) elucidate the association between rs1800975 and PTB.

Results

We reviewed all published papers for PTB phenotype and SNP rs1800795 genotype. Maternal genotype and fetal genotype were analyzed separately and the analyses were stratified by population. The PTB phenotype was defined as gestational age (GA) < 37 weeks, but results from earlier GA were selected when available. All studies were compared by genotype (CC versus CG+GG), based on functional studies.

For the maternal genotype analysis, 1,165 PTBs and 3,830 term controls were evaluated. Populations were stratified into women of European descent (for whom the most data were available) and women of heterogeneous origin or admixed populations. All ancestry was self-reported. Women of European descent had a summary odds ratio (OR) of 0.68, (95% confidence interval (CI) 0.51 – 0.91), indicating that the CC genotype is protective against PTB. The result for non-European women was not statistically significant (OR 1.01, 95% CI 0.59 - 1.75). For the fetal genotype analysis, four studies were included; there was no significant association with PTB (OR 0.98, 95% CI 0.72 - 1.33). Sensitivity analysis showed that preterm premature rupture of membrane (PPROM) may be a confounding factor contributing to phenotype heterogeneity.

Conclusions

IL6 SNP rs1800795 genotype CC is protective against PTB in women of European descent. It is not significant in other heterogeneous or admixed populations, or in fetal genotype analysis.

Population structure is an important confounding factor that should be controlled for in studies of PTB.

Respiratory function in healthy late preterm infants delivered at 33-36 weeks of gestation

OBJECTIVE

To compare pulmonary function testing including respiratory compliance (Crs) and time to peak tidal expiratory flow to expiratory time (TPTEF:TE) at term corrected age in healthy infants born at 33-36 weeks of gestation versus healthy infants delivered at term.

STUDY DESIGN

We performed a prospective cohort study of late preterm infants born at 33-36 weeks without clinical respiratory disease (<12 hours of >0.21 fraction of inspired oxygen) and studied at term corrected age. The comparison group was term infants matched for race and sex to the preterm infants and studied within 72 hours of delivery. Crs was measured with the single breath occlusion technique. A minimum of 50 flow-volume loops were collected to estimate TPTEF:TE.

RESULTS

Late preterm infants (n = 31; mean gestational age 34.1 weeks, birth weight 2150 g) and 31 term infants were studied at term corrected age. The late preterm infants had decreased Crs (1.14 vs 1.32 mL/cm H(2)O/kg; P < .02) and decreased TPTEF:TE (0.308 vs 0.423; P < .01) when compared with the term infants. Late preterm infants also had an increased respiratory resistance (0.064 vs 0.043 cm H(2)O/mL/s; P < .01).

CONCLUSIONS

Healthy late preterm infants (33-36 weeks of gestation) studied at term corrected age have altered pulmonary function when compared with healthy term infants.

Increasing rates of prematurity and epidemiology of late preterm birth

Preterm birth rates in Australia have risen in the last two decades, mostly accounted for by the rise in late preterm births. Late preterm births (34-36 weeks) comprise 70% of all preterm births, which translates to approximately 16,000 births annually in Australia. The precise causes for this trend are unclear; however, possible aetiologies include increasing maternal age, increased use of artificial reproductive technologies and increased multiple births. Compared with term-born children, late preterm children not only have increased mortality and in-hospital morbidity including respiratory difficulties, but also long-term cognitive, school performance, behaviour and psychiatric problems. The potential public health and educational burden of late preterm birth is considerable. More research is required in this area to understand the risk factors for late preterm birth and to help identify those children at highest risk of developmental deficits.

Early neonatal outcome in late preterms

OBJECTIVES

To study the maternal risk factors, morbidity, mortality of late preterm in comparison to term neonates.

METHODS

This Cohort study involved two hundred fifty consecutively born late preterm and equal number of term newborns delivered in a tertiary care hospital. They were followed till discharge for morbidities and mortality. Detailed maternal and neonatal factors were studied and compared between the two groups.

RESULTS

Late preterm babies constituted 55% of all live preterm births during the study period. The odds of babies developing major morbidity was significantly more in those whose mothers had hypertension and infections (OR 2.69 95% CI: 1.55, 4.68 and 2.08, 95% CI: 1.6, 2.71 respectively). In the study group, 42.4% and 20.8% babies suffered major and minor morbidity compared to 8.4% and 6.8% of term controls respectively. Late preterm neonates had significantly higher odds of developing morbidity like respiratory distress (12.4% vs. 5.6%, OR 2.21, 95%CI 1.21,4.11), need for non invasive(17.3% vs. 5.7%, OR 3.05 95% CI 1.69, 5.47) and invasive ventilation (14.6% vs. 1.7%, OR 8.62, 95% CI 3.09, 24.04), sepsis (20.8% vs. 5.2%, OR 5.20, 95% CI 2.71, 9.99), seizures (22.8% vs. 4.8%, OR 4.75 95%CI 2.61, 8.63), shock (17.6% vs. 4.4%, OR 4.00 95% CI 2.12,7.56), and jaundice (26% vs. 6%, OR 4.33 95%CI 2.54, 7.39). By logistic regression, the odds of developing major morbidity decreased with increasing gestational age (aOR 0.28 95% CI 0.18, 0.45; p < 0.001) and increased with hypertensive disease of pregnancy (aOR 2.16 95% CI 1.09, 4.260; p = 0.026).

CONCLUSIONS

Late preterm neonates have significantly more mortality and morbidity compared to term controls. Maternal hypertension and lower gestational age are the strongest predictors of morbidity.

Obstetric management of moderate and late preterm labour

Moderate and late preterm births account for the majority of preterm babies. The common perception that birth at 32-36 weeks' gestation carries few risks is now being challenged, as these babies have increased risk of neonatal mortality and morbidity. However, spontaneous labour at this gestation frequently has no specific, easily identifiable precursor, although preterm birth per se has a number of epidemiological and clinical associations. Prediction and prevention of preterm birth is currently largely aimed at identifying women at high risk such as those with previous preterm birth, and targeting intervention at this group. Both cervical length assessment and fibronectin testing permit some modification of the likelihood of preterm birth in this group. Progesterone treatment for the prevention of preterm birth is currently being researched widely, and appears a potentially promising strategy. Babies born at 32-36 weeks' gestation need careful monitoring in labour, with modification of intervention in labour due to their prematurity.

Behavior Problems in Relation to Sustained Selective Attention Skills of Moderately Preterm Children

Attention skills may form an important developmental mechanism. A mediation model was examined in which behavioral problems of moderately preterm and term children at school age are explained by attention performance. Parents and teachers completed behavioral assessments of 348 moderately preterm children and 182 term children at 8 years of age. Children were administered a test of sustained selective attention. Preterm birth was associated with more behavioral and attention difficulties. Gestational age, prenatal maternal smoking, and gender were associated with mothers', fathers', and teachers' reports of children's problem behavior. Sustained selective attention partially mediated the relationship between birth status and problem behavior. Development of attention skills should be an important focus for future research in moderately preterm children.