Trends in All-Cause Mortality across Gestational Age in Days for Children Born at Term

Background

Term birth is a gestational age from 259 days to 293 days. However trends in mortality according to gestational ages in days have not yet been described in this time period.

Methods and Findings

Based on nation-wide registries, we conducted a population-based cohort study among all children born at term in Denmark from 1997 to 2004 to estimate differences in mortality across gestational ages in days among singletons born at term. We studied early-neonatal mortality, neonatal mortality, infant mortality, and five-year mortality. Children were followed from birth up to the last day of the defined mortality period or December 31, 2009. A total of 360,375 singletons born between 259 and 293 days of gestation were included in the study. Mortality decreased with increasing gestational age in days and the highest mortality was observed among children born at 37 week of gestation. A similar pattern was observed when analyses were restricted to children born to by mothers without pregnancy complications.

Conclusions

This study demonstrates heterogeneity in mortality rates even among singletons born at term. The highest mortality was observed among children born 37 weeks of gestation, which call for cautions when inducing labor in term pregnancies just reaching 37 weeks of gestation. The findings support that 37 weeks of gestation should be defined as early term.     

Executive functions of six-year-old boys with normal birth weight and gestational age

Impaired fetal development, reflected by low birth weight or prematurity, predicts an increased risk for psychopathology, especially attention deficit hyperactivity disorder (ADHD). Such effects cut across the normal range of birth weight and gestation. Despite the strength of existing epidemiological data, cognitive pathways that link fetal development to mental health are largely unknown. In this study we examined the relation of birth weight (>2500 g) and gestational age (37-41 weeks) within the normal range with specific executive functions in 195 Singaporean six-year-old boys of Chinese ethnicity. Birth weight adjusted for gestational age was used as indicator of fetal growth while gestational age was indicative of fetal maturity. Linear regression revealed that increased fetal growth within the normal range is associated with an improved ability to learn rules during the intra/extra-dimensional shift task and to retain visual information for short period of time during the delayed matching to sample task. Moreover, faster and consistent reaction times during the stop-signal task were observed among boys born at term, but with higher gestational age. Hence, even among boys born at term with normal birth weight, variations in fetal growth and maturity showed distinct effects on specific executive functions.     

Gestational Age and Neonatal Brain Microstructure in Term Born Infants: A Birth Cohort Study

Objective

Understanding healthy brain development in utero is crucial in order to detect abnormal developmental trajectories due to developmental disorders. However, in most studies neuroimaging was done after a significant postnatal period, and in those studies that performed neuroimaging on fetuses, the quality of data has been affected due to complications of scanning during pregnancy. To understand healthy brain development between 37–41 weeks of gestational age, our study assessed the in utero growth of the brain in healthy term born babies with DTI scanning soon after birth.

Methods

A cohort of 93 infants recruited from maternity hospitals in Singapore underwent diffusion tensor imaging between 5 to 17 days after birth. We did a cross-sectional examination of white matter microstructure of the brain among healthy term infants as a function of gestational age via voxel-based analysis on fractional anisotropy.

Results

Greater gestational age at birth in term infants was associated with larger fractional anisotropy values in early developing brain regions, when corrected for age at scan. Specifically, it was associated with a cluster located at the corpus callosum (corrected p<0.001), as well as another cluster spanning areas of the anterior corona radiata, anterior limb of internal capsule, and external capsule (corrected p<0.001).

Conclusions

Our findings show variation in brain maturation associated with gestational age amongst ‘term’ infants, with increased brain maturation when born with a relatively higher gestational age in comparison to those infants born with a relatively younger gestational age. Future studies should explore if these differences in brain maturation between 37 and 41 weeks of gestational age will persist over time due to development outside the womb.     

Growth and developmental outcomes of three high-risk infant rhesus macaques (Macaca mulatta)

Infants classified as "high risk" are born with a greater chance of developing medical complications at birth, and may have cognitive and other developmental complications later in life. Very few reports exist regarding the survival and outcome of such infants in primate colonies. Here we present early growth and developmental data on three high-risk infant rhesus macaques (one female and two males) that were born either with intrauterine growth restriction (IUGR; born below the 1st birth weight percentile for gestational age) or extremely prematurely (at gestational days 128 and 140; mean full-term gestation=164 days). We compared the outcome of these infants with that of healthy controls born at term and found no gross developmental delays in these infants with respect to growth, neonatal reflex and motor skill development, early cognitive development, or social behavior. Neurological and cognitive assessments were compared in terms of both postnatal and gestational age. The survival of these infants was dependent on a 24-hr staffed nursery and a fluid protocol that catered to each high-risk infant's individual needs. When such measures are implemented, infants such as these have a good chance of survival and can serve as excellent models for high-risk human babies and their subsequent development.     

Are preterm black infants larger than preterm white infants, or are they more misclassified?

In birth certificate data for Massachusetts resident births from 1978 to 1982, 12-27% of births purportedly under 31 weeks of gestation were probably misclassified, i.e. had birthweight greater than or equal to 2500 g. Correcting for maldistribution of births removed 34% and 23%, respectively, of black and white births with reported gestational ages less than 36 weeks but with implausible weights. Percentages of unknown and incomplete reports of last menstrual period were also significantly higher for blacks. After adjustment, preterm black infants weighed less than whites at each gestational age. The proportion of infants less than 2500 g born at term (greater than or equal to 37 weeks gestation) was higher (although not significantly) among blacks. These findings are consistent with hypotheses that low socioeconomic status negatively affects the rate of intrauterine growth.     

Patterns of low birth weight in the Bengali newborns

This paper examines the distribution of low birth weight (2500 g or less) by gestation time, sex, maternal age, parity (birth order), socioeconomic conditions, and season of birth among 5117 single live births born to Bengali mothers at the Ramakrishna Mission Seva Pratisthan Hospital in Calcutta, India. Preterm infants have low birth weight significantly more often than their full term counterparts. Female infants have low birth weights significantly more often than male infants. The infants of poor mothers have lower birth weights in higher order births more often than infants of higher orders born to well-off mothers. Teenaged mothers produce low birth weight babies significantly more often than older mothers. Although the relationship is not significant, low birth weight infants occur more often among 1st and late born infants and less often among 2nd born infants. The season of birth is not significantly associated with birth weight. Less than 10% of low birth weight infants are pre-term, while the rest are full term. The great majority of low birth weight infants are small-for-gestational-age; the minority are small due to curtailed gestational age. The proportion of infants weighing less than 2001 g is only 9%; this figure tallies closely with earlier studies of India.     

Risk of premature birth in multifetal pregnancy.

The risk of preterm delivery (< 37 weeks of gestation) is approximately nine times higher in women with multifetal pregnancies than in women with singleton pregnancies. However, it is possible that the risk will vary according to gestational week. To assess the risk of premature birth within 1 week by gestational age among multifetal pregnancies and compare the estimated risk with that of singleton pregnancies, we analyzed 6,036,475 infants born in singleton pregnancies and 90,887 infants born in multifetal pregnancies in Japan (> or =22 weeks) over the 5-year period 1989-1993. An estimate of the risk of birth within 1 week at gestational week n was obtained by dividing the number of infants delivered at gestational week n by the number of infants delivered at or beyond gestational week n. The risk at 22 weeks was 0.9 per 1000 fetuses for singleton pregnancies and 5.0 per 1000 for multifetal pregnancies. The risk remained relatively stable until 27 weeks of gestation, then sharply increased toward 36 weeks of gestation in both singleton and multifetal pregnancies. The odds ratio for birth within 1 week for fetuses of multifetal pregnancies compared with fetuses of singleton pregnancies was 5.9 (95% CI, 5.4-6.5) at 22 weeks of gestation, increasing gradually with increasing gestational age until 33 weeks of gestation (13.7; 95% CI, 13.1-14.2) but declining thereafter to 8.8 (95% CI, 8.6-8.9) at 36 weeks of gestation. Results of data analysis for each year of the 5-year period did not differ substantially.     

Association of Gestational Age at Birth with Reasons for Subsequent Hospitalisation: 18 Years of Follow-Up in a Western Australian Population Study

Background

Preterm infants are at a higher risk of hospitalisation following discharge from the hospital after birth. The reasons for rehospitalisation and the association with gestational age are not well understood.

Methods

This was a retrospective birth cohort study of all live, singleton infants born in Western Australia between 1^st January 1980 and 31^st December 2010, followed to 18 years of age. Risks of rehospitalisation following birth discharge by principal diagnoses were compared for gestational age categories (<32, 32–33, 34–36, 37–38 weeks) and term births (39–41weeks). Causes of hospitalisations at various gestational age categories were identified using ICD-based discharge diagnostic codes.

Results

Risk of rehospitalisation was inversely correlated with gestational age. Growth-related concerns were the main causes for rehospitalisation in the neonatal period (<1 month of age) for all gestational ages. Infection was the most common reason for hospitalisation from 29 days to 1 year of age, and up to 5 years of age. Injury-related hospitalisations increased in prevalence from 5 years to 18 years of age. Risk of rehospitalisation was higher for all preterm infants for most causes.

Conclusions

The highest risks of rehospitalisation were for infection related causes for most GA categories. Compared with full term born infants, those born at shorter GA remain vulnerable to subsequent hospitalisation for a variety of causes up until 18 years of age.     

Antenatal Maternal Emotional Distress and Duration of Pregnancy

Objective(s)

We sought to prospectively study the association between antenatal emotional distress and gestational length at birth as well as preterm birth.

Study Design

We followed up 40,077 primiparous women in the Norwegian Mother and Child Cohort Study. Emotional distress was reported in a short form of the Hopkins Symptom Checklist-25 (SCL-5) at 17 and 30 weeks of gestation. Gestational length at birth, obtained from the Medical Birth Registry of Norway, was used as continuous (gestational length in days) and categorized (early preterm (22–31 weeks) and late preterm (32–36 weeks) versus term birth (≥37 weeks)) outcome, using linear and logistic regression analysis, respectively. Births were divided into spontaneous and provider-initiated.

Results

Of all women, 7.4% reported emotional distress at 17 weeks, 6.0% at 30 weeks and 5.1% had a preterm birth. All measurements of emotional distress at 30 weeks were significantly associated with a reduction of gestational length, in days, for provider-initiated births at term. Emotional distress at 30 weeks showed a reduced duration of pregnancy at birth of 2.40 days for provider-initiated births at term. An increase in emotional distress from 17 to 30 weeks was associated with a reduction of gestational length at birth of 2.13 days for provider-initiated births at term. Sustained high emotional distress was associated with a reduction of gestational length at birth of 2.82 days for provider-initiated births. Emotional distress did not increase the risk of either early or late preterm birth.

Conclusion

Emotional distress at 30 weeks, an increase in emotional distress from 17 to 30 weeks and sustained high levels of emotional distress were associated with a reduction in gestational length in days for provider-initiated term birth. We found no significant association between emotional distress and the risk of preterm birth.     

Premature birth and circadian preference in young adulthood: evidence from two birth cohorts

A preference for eveningness (being a “night owl”) and preterm birth (<37 weeks of gestation) are associated with similar adversities, such as elevated blood pressure, impaired glucose regulation, poorer physical fitness, and lower mood. Yet, it remains unclear if and how preterm birth is associated with circadian preference. The aim of this study was to assess this association across the whole gestation range, using both objective and subjective measurements of circadian preference.

Circadian preference was measured among 594 young adults (mean age 24.3 years, SD 1.3) from two cohorts: the ESTER study and the Arvo Ylppö Longitudinal Study. We compared 83 participants born early preterm (<34 weeks) and 165 late preterm (34 to <37 weeks) with those born at term (≥37 weeks, n = 346). We also compared very low birth weight (VLBW, <1500 g) participants with term-born controls. We obtained objective sleep data with actigraphs that were worn for a mean period of 6.8 (SD 1.4) nights. Our primary outcome was sleep midpoint during weekdays and weekend. The sleep midpoint is the half-way time between falling asleep and waking up, and it represents sleep timing. We also investigated subjective chronotype with the Morningness–Eveningness Questionnaire (MEQ) in 688 (n = 138/221/329) ESTER participants. The MEQ consists of 19 questions, which estimates the respondent to be of a “morning”, “evening,” or “intermediate” chronotype, based on the Morningness–Eveningness Score (MES). We analyzed the data from the actigraphs and the MES with three linear regression models, and analyzed distribution of the chronotype class with Pearson χ2.

There were no consistent differences across the study groups in sleep midpoint. As compared with those born at term, the mean differences in minutes:seconds and 95% confidence intervals for the sleep midpoint were: early preterm weekdays 11:47 (?8:34 to 32:08), early preterm weekend 4:14 (?19:45 to 28:13), late preterm weekdays ?10:28 (?26:16 to 5:21), and late preterm weekend ?1:29 (?20:36 to 17:37). There was no difference in sleep timing between VLBW-participants and controls either. The distribution of chronotype in the MEQ among all participants was 12.4% morningness, 65.4% intermediate, and 22.2% eveningness. The distribution of the subjective chronotype class did not differ between the three gestational age groups (p = 0.98). The linear regression models did not show any influence of gestational age group or VLBW status on the MES (all p > 0.5).

We found no consistent differences between adults born early or late preterm and those born at term in circadian preference. The earlier circadian preference previously observed in those born smallest is unlikely to extend across the whole range of preterm birth.     

The management and outcome of higher order multifetal pregnancies: obstetric, neonatal and follow-up data.

The objective of this study was to describe current obstetric, neonatal, and long-term neurodevelopmental outcomes of higher order multifetal gestations (> or = 3 fetuses) in the 1990s. We also intended to identify a target gestational age at which neonatal and neurodevelopmental morbidities are low. Records from all multifetal pregnancies (> or = 3 viable fetuses > or = 20 weeks gestation) delivered at the two perinatal centers in Toronto, Ontario, Canada during the study period (January 1, 1990-December 31, 1996) were reviewed. Data were collected on obstetric, neonatal, and long-term neurodevelopmental outcomes. Follow up data were gathered regarding the presence of a severe deficit in four categories (vision, hearing, cognition, and motor skills). Statistical analysis was performed to determine a gestational age at which a significant decrease in deficit occurred. During the study period 165 multifetal pregnancies were delivered. This resulted in 511 fetuses, of which 496 were live births. Of these 496 infants, 453 survived to discharge. Follow up data were obtained on 332 (73.3 per cent) infants. Infant survival increased with gestational age, and was approximately 90 per cent or greater at 26 weeks or more. Of all infants followed, the proportion of those without deficit increased with increasing gestational age, such that the percent without deficit was 96.9 at 31 weeks or greater. Of all infants followed, 301 (90.7 per cent) had no deficit. Statistical analysis revealed a significant difference in long-term neurodevelopmental outcome between infants born before and after 28 weeks gestation. The incidence of a major deficit was 44.1 per cent for those born earlier than and 5.4 per cent for those born later than this gestational age (p = 0.001). In our cohort, survival figures were high. Even in lower gestational groupings, survival was high, but not without serious concerns about severe morbidity. This information is useful when counseling parents of higher order multifetal pregnancies.     

Variation in early neonatal mortality for different types of fetal growth retardation

Birth and first-48-hr death records were analyzed for 10,024 liveborn infants in Mexico City and 12,786 liveborn infants in Santa Cruz, Bolivia. The objective of the analysis was to characterize the early postnatal mortality rates for different types of fetal growth retardation and prematurity. Infants who were delivered prior to 37 weeks of gestation had 23-100 times the mortality risk of infants born at full term and normal weight. Light-for-gestational-age infants (birth weight less than 2,900 g) were further divided into proportionately growth-retarded with normal Rohrer's index (weight/height) and disproportionately growth-retarded with low Rohrer's index. The proportionately growth-retarded infant had nearly twice the mortality of the full-term, appropriate-weight infants, whereas the disproportionately growth-retarded infants had 2.9-5.7 times the mortality rate of the full-term, appropriate-weight infants. There were some differences between samples in mortality rates and prevalence of the different classes of small infants, but the pattern of mortality within samples was consistent between samples.     

The effect of gestational age and labour on markers of lipid and protein oxidation in cord plasma

There are many potential sources of reactive oxidants around the time of birth and pre-term infants are considered to be particularly vulnerable to oxidative injury. To gain insight into these processes, we have measured biomarkers of lipid and protein oxidation in umbilical cord plasma and related concentrations to mode of delivery and gestational age. Protein carbonyls were measured by ELISA and malondialdehyde (MDA) by HPLC after reaction with thiobarbituric acid, for 54 pre-term (< or = 36 weeks gestational age) and 43 term infants. Protein carbonyls were significantly lower in pre-term (median for < 32 weeks gestational age 0.048nmol/mg protein) than in term infants (0.105 nmol/mg, p = 0.004), and were unrelated to mode of delivery. In contrast, MDA concentrations were higher in the very pre-term (<32 weeks gestation) group (2.47 compared with 1.83 microM for term infants, p < 0.0001). MDA concentrations were higher in infants who were born with labour compared with elective caesarean section. Pre-eclampsia in the mother was associated with higher cord blood MDA concentrations. The MDA results are consistent with other studies of this marker and could be interpreted as indicating increased oxidative stress associated with prematurity and labour. However, the lower protein carbonyls in pre-term infants would lead to an opposite interpretation. More information is needed on the source and fate of these and other biomarkers before drawing strong conclusions on how they reflect oxidative stress in this and other clinical situations.     

Neonatal White Matter Abnormalities an Important Predictor of Neurocognitive Outcome for Very Preterm Children

Background

Cerebral white matter abnormalities on term MRI are a strong predictor of motor disability in children born very preterm. However, their contribution to cognitive impairment is less certain.

Objective

Examine relationships between the presence and severity of cerebral white matter abnormalities on neonatal MRI and a range of neurocognitive outcomes assessed at ages 4 and 6 years.

Design/Methods

The study sample consisted of a regionally representative cohort of 104 very preterm (≤32 weeks gestation) infants born from 1998–2000 and a comparison group of 107 full-term infants. At term equivalent, all preterm infants underwent a structural MRI scan that was analyzed qualitatively for the presence and severity of cerebral white matter abnormalities, including cysts, signal abnormalities, loss of white matter volume, ventriculomegaly, and corpus callosal thinning/myelination. At corrected ages 4 and 6 years, all children underwent a comprehensive neurodevelopmental assessment that included measures of general intellectual ability, language development, and executive functioning.

Results

At 4 and 6 years, very preterm children without cerebral white matter abnormalities showed no apparent neurocognitive impairments relative to their full-term peers on any of the domain specific measures of intelligence, language, and executive functioning. In contrast, children born very preterm with mild and moderate-to-severe white matter abnormalities were characterized by performance impairments across all measures and time points, with more severe cerebral abnormalities being associated with increased risks of cognitive impairment. These associations persisted after adjustment for gender, neonatal medical risk factors, and family social risk.

Conclusions

Findings highlight the importance of cerebral white matter connectivity for later intact cognitive functioning amongst children born very preterm. Preterm born children without cerebral white matter abnormalities on their term MRI appear to be spared many of the cognitive impairments commonly associated with preterm birth. Further follow-up will be important to assess whether this finding persists into the school years.     

Determinants of intrauterine growth retardation: evidence against maternal depletion

This analysis examines the relationship between length of preceding birth interval and risk of intrauterine growth retardation using data on Swedish infants from the 1973 World Health Organization study of perinatal mortality. Results of a multivariate logit analysis demonstrate that the lower than average mean birth weight of infants born after short birth intervals cannot be completely attributed to their shorter mean gestation length. Infants born after birth intervals of 12 months or less are 30% more likely to be small for gestational age (SGA) than infants born 18-59 months after the previous birth, even when the effects of maternal age and parity are controlled. The results obtained here do not support maternal depletion as an explanation for the association between short birth intervals and elevated risk of SGA, since there is no evidence of an attenuation of the risk of SGA with increasing length of interval in the under 18 month birth interval range.     

The Effect of Gestational Age and Labour on Markers of Lipid and Protein Oxidation in Cord Plasma

There are many potential sources of reactive oxidants around the time of birth and pre-term infants are considered to be particularly vulnerable to oxidative injury. To gain insight into these processes, we have measured biomarkers of lipid and protein oxidation in umbilical cord plasma and related concentrations to mode of delivery and gestational age. Protein carbonyls were measured by ELISA and malondialdehyde (MDA) by HPLC after reaction with thiobarbituric acid, for 54 pre-term (≤36 weeks gestational age) and 43 term infants. Protein carbonyls were significantly lower in pre-term (median for <32 weeks gestational age 0.048?nmol/mg protein) than in term infants (0.105?nmol/mg, p=0.004), and were unrelated to mode of delivery. In contrast, MDA concentrations were higher in the very pre-term (<32 weeks gestation) group (2.47 compared with 1.83?μM for term infants, p<0.0001). MDA concentrations were higher in infants who were born with labour compared with elective caesarean section. Pre-eclampsia in the mother was associated with higher cord blood MDA concentrations. The MDA results are consistent with other studies of this marker and could be interpreted as indicating increased oxidative stress associated with prematurity and labour. However, the lower protein carbonyls in pre-term infants would lead to an opposite interpretation. More information is needed on the source and fate of these and other biomarkers before drawing strong conclusions on how they reflect oxidative stress in this and other clinical situations.     

Morphological traits and common illness in newborn infants

The present study focussed on neonates morbidity in connection with the morphological traits in the individual relative to the population average and in connection with the fluctuating asymmetry (FA) in 8 bilateral traits. The sample comprised two categories of newborn infants: 1) 1088 full term children, in which body weight (W), body height (H) and head circumference (HC) were measured on the day of birth; and 2) 216 infants of various gestation age (from 26 to 41 weeks) in which 6 measurements of upper and lower arm breadth, plus ear length and breadth on both sides of the body, were made during the first 72 hours of life. Relevant vital statistics were also obtained from parents. The following major categories of morbidity were observed in our samples: jaundice, respiratory diseases, cardiovascular diseases, urinary tract infections (only in the second sample), haematological diseases and ‘varia’. The results show that W, H, HC and W/H² index are significantly correlated with a predisposition to various categories of morbidity. For W and W/H² index, this correlation remains significant even after adjustment for diverse anthropometric and demographic variables. In the case of urinary tract infection, the contribution of HC also remains significant even after the adjustment procedure. Gestational age and cardiovascular illnesses yielded significant correlations with mean FA. There was an evident decrease in mean FA upon increase of gestational age. The mean FA of infants suffering from cardiovascular morbidity displays the same trend, although it is consistently higher compared to the total group of infants in the respective gestational age.     

巨大儿与足月适于胎龄儿2 岁以内的体格及智能发育的对照研究

目的：了解出生体重对婴儿早期体格及智能发育的影响,为巨大儿的早期保健及健康教育提供理论依据。方法：在我院2007 年1 月～2009 年12 月出生的巨大儿及足月适于胎龄儿中,随机选取50 例足月巨大儿作为观察组(除外生后低血糖、窒息、高胆 红素血症者),及50 例与之匹配的足月适于胎龄儿作为对照组。两组孕周、生后评分、性别比例、父母收入、喂养方式比较差异无统 计学意义。定期检查和记录两组的各体格及智能发育评估指标,了解两组婴儿体重指数及智能发育特点,采用Gesell发育诊断量 表对两组进行评价。结果：观察组出生后3、6、9、12、18、24 个月的超重发生率均显著高于对照组,差异均有统计学意义(P<0.05), 观察组随年龄增长体重指数有下降趋势,6 月龄时体重指数最高,24 月时最低;观察组6 月时大运动发育商数为(100.86± 3.34), 对照组则为(104.58± 3.19),差异有统计学意义(P<0.05),12 月时,观察组的发育商数已接近正常,两组大运动、精细运动、适应行 为、语言和个人- 社会性行为5 个方面的的差异均无统计学意义(P>0.05)。结论：巨大儿在2 岁以内的体重指数显著高于足月适于 胎龄儿;较重的体重负荷可对其生后6 月内的大运动造成不良影响。     

Acute Histologic Chorioamnionitis Is a Risk Factor for Adverse Neonatal Outcome in Late Preterm Birth after Preterm Premature Rupture of Membranes

Background

The objective of this study was to determine whether acute histologic chorioamnionitis is associated with adverse neonatal outcomes in late preterm infants who were born after preterm PROM.

Methodology/Principal Findings

The relationship between the presence of acute histologic chorioamnionitis and adverse neonatal outcome was examined in patients with preterm PROM who delivered singleton preterm newborns between 34 weeks and 36 6/7 weeks of gestation. Nonparametric statistics were used for data analysis. The frequency of acute histologic chorioamnionitis was 24% in patients with preterm PROM who delivered preterm newborns between 34 weeks and 36 6/7 weeks of gestation. Newborns born to mothers with histologic chorioamnionitis had significantly higher rates of adverse neonatal outcome (74% vs 51%; p<0.005) than those without histologic chorioamnionitis. This relationship remained significant after adjustment for gestational age at preterm PROM, gestational age at delivery, and exposure to antenatal corticosteroids.

Conclusions/Significance

The presence of acute histologic chorioamnionitis is associated with adverse neonatal outcome in late preterm infants born to mothers with preterm PROM.     

Influence of postconceptual age on the electromyographic characteristics in newborns

The purpose of the study was to investigate the neuromuscular state in the preterm infants using surface electromyography (EMG). Ten preterm (gestational age, 31–32 weeks) and ten term infants (gestational age, 38–39 weeks) participated in the study in the second, fourth and sixth postnatal weeks. Linear and novel nonlinear parameters were used for the treatment of the interference EMG (iEMG) in four muscles (mm. bic. br. dext., trie. br. dext, tib. ant. sin., and gastr. sin.). In the preterm infants aged 33–37 weeks, both linear and nonlinear iEMG parameters were significantly lower in comparison to the term infants. Thus, the iEMG of the preterm infants was characterized by a more primitive time-domain structure and lower amplitude and spectrum frequency. In addition, unlike in term newborns, the lifetime dynamics of the iEMG parameters in the preterm infants was retarded. Thus, the motor system of a preterm infant is likely to be less prepared for postnatal life due to the shorter stay in utero. Nonetheless, the iEMG of the preterm infants may be characterized as more complex in comparison to the term newborns of the same postconceptual age. This may be attributed to the new postnatal sensory stimuli.