Optimizing care and outcome for late-preterm (near-term) infants: a summary of the workshop sponsored by the National Institute of Child Health and Human Development

Precursors for late preterm birth in singleton gestations

OBJECTIVE

To characterize precursors for late preterm birth in singletons and incidences of neonatal morbidities and perinatal mortality by gestational age and precursor.

METHODS

Using retrospective observational data, we compared 15,136 gestations born late preterm with 170,593 deliveries between 37 0/7 and 41 6/7 weeks. We defined the following categories of precursors for late preterm delivery: "spontaneous labor," "premature rupture of the membranes (preterm PROM)," "indicated" delivery, and "unknown." Incidences of neonatal morbidities were calculated according to category of precursor stratified by gestational age at delivery. Neonatal morbidities and mortality associated with potentially avoidable deliveries (eg, "soft" precursors or elective) were compared between late preterm births and neonates born at 37-40 weeks.

RESULTS

Late preterm birth comprised 7.8% of all births and 65.7% of preterm births. Percentages of precursors were 29.8% spontaneous labor, 32.3% preterm PROM, 31.8% "indicated" (obstetric, maternal, or fetal condition), and 6.1% unknown. Different precursors for delivery were associated with varying incidences of neonatal morbidity. One in 15 neonates delivered late preterm for "soft" or elective precursors, and neonatal morbidity and mortality were increased compared with delivery at or after 37 weeks for these same indications.

CONCLUSION

A significant number of late preterm births were potentially avoidable. Elective deliveries should be postponed until 39 weeks of gestation.

LEVEL OF EVIDENCE

II.

Reduction in elective delivery at <39 weeks of gestation: comparative effectiveness of 3 approaches to change and the impact on neonatal intensive care admission and stillbirth

OBJECTIVE

No studies exist that have examined the effectiveness of different approaches to a reduction in elective early term deliveries or the effect of such policies on newborn intensive care admissions and stillbirth rates.

STUDY DESIGN

We conducted a retrospective cohort study of prospectively collected data and examined outcomes in 27 hospitals before and after implementation of 1 of 3 strategies for the reduction of elective early term deliveries.

RESULTS

Elective early term delivery was reduced from 9.6-4.3% of deliveries, and the rate of term neonatal intensive care admissions fell by 16%. We observed no increase in still births. The greatest improvement was seen when elective deliveries at <39 weeks were not allowed by hospital personnel.

CONCLUSION

Physician education and the adoption of policies backed only by peer review are less effective than "hard stop" hospital policies to prevent this practice. A 5% rate of elective early term delivery would be reasonable as a national quality benchmark.

Evidence-based systematic review: effects of oral motor interventions on feeding and swallowing in preterm infants

PURPOSE

To conduct an evidence-based systematic review and provide an estimate of the effects of oral motor interventions (OMIs) on feeding/swallowing outcomes (both physiological and functional) and pulmonary health in preterm infants.

METHOD

A systematic search of the literature published from 1960 to 2007 was conducted. Articles meeting the selection criteria were appraised by 2 reviewers and vetted by a 3rd for methodological quality.

RESULTS

Twelve studies were included and focused on 3 OMIs-nonnutritive sucking (NNS), oral/perioral stimulation, and NNS plus oral/perioral stimulation. Six studies addressed the effects of OMI on the feeding/swallowing physiology outcomes of feeding efficiency or sucking pressures. Ten studies addressed the functional feeding/swallowing outcomes of oral feeding or weight gain/growth. No studies reported data on pulmonary health. Methodological quality varied greatly. NNS alone and with oral/perioral stimulation showed strong positive findings for improvement in some feeding/swallowing physiology variables and for reducing transition time to oral feeding. Prefeeding stimulation showed equivocal results across the targeted outcomes. None of the OMIs provided consistent positive results on weight gain/growth.

CONCLUSIONS

Although some OMIs show promise for enhancing feeding/swallowing in preterm infants, methodological limitations and variations in results across studies warrant careful consideration of their clinical use.

Morbidity and discharge timing of late preterm newborns

Late preterm newborns (LPNs), those with gestational ages (GAs) between 34 weeks and 36 weeks 6 days, account for 70% of preterm births. Because they have a mature appearance and are often cared for in a well baby nursery (WBN), parents may anticipate that the nursery course will be similar to that of a term infant and that their newborn will be discharged with his/her mother. How frequently their hospitalizations are prolonged beyond that of their mothers and the morbidities associated with prolonged hospitalization (PH) have not been well described. The objectives of the study were to (1) determine the proportion of LPNs with a PH and (2) describe the most common morbidities in LPNs and identify those associated with PH. The authors conducted retrospective chart reviews of the neonatal courses of LPNs born between December 2002 and April 2007 at the University of Utah Hospital. They compared maternal and newborn discharge dates to determine the proportion of LPNs with a PH and calculated frequencies of conditions and interventions indicating morbidity and identified associations between each of the conditions/interventions and PH. Of 235 LPNs, 94 (40%) had a PH; 75% of 34-week LPNs had a PH compared with 50% of those with GAs of 35 weeks and 25% of those with GAs of 36 weeks. The most common conditions/interventions were an oxygen need, phototherapy for jaundice, and hypothermia requiring an isolette. A need for nasogastric feeding and antibiotic administration for >3 days was consistently associated with a PH. LPNs whose only intervention was phototherapy for jaundice or IV antibiotics for <3 days did not have a PH. As a group, two thirds of LPNs experienced one or more conditions/interventions indicating morbidity, and 40% had a PH. Both were much more common in LPNs with GAs of 34 weeks compared with LPNs with GAs of 36 weeks. Nursery clinicians should counsel parents of LPNs regarding the likely possibility of morbidity and PH.

Clinical issues in the management of late preterm infants

Prematurity is defined as birth before 37 weeks of gestation and is the major determinant of morbidity and mortality in newborns. The gestational ages known as near term or late preterm represent about 75% of preterm births and are the fastest growing subgroups of premature infants. These infants range in gestational age from 34 0/7 to 36 6/7 weeks and are at greater risk of morbidity, such as respiratory complications, temperature instability, hypoglycemia, kernicterus, feeding problems, neonatal intensive care unit admissions, and adverse neurological sequelae when compared with term infants. Long-term neurological and school-age outcomes of late preterm infants are concerns of major public health importance because even a minor increase in the rate of neurological disability and scholastic failure in this group can have a huge impact on the health care and educational systems. There is an urgent need to educate health care providers and parents about the vulnerability of late preterm infants, who are in need of diligent monitoring and care during the initial hospital stay and a comprehensive follow-up plan for post neonatal and long-term evaluations. Clinicians involved in the day-to-day care of late preterm infants, as well as those developing guidelines and recommendations, would benefit from having a clear understanding of the potential differences in risks faced by these infants, compared with their more mature counterparts.

Morbidity rates in late preterms born to HIV-mothers

The rate of late preterm delivery has increased in the general population, and the late preterm infants have a higher incidence of morbidity compared to term newborns. Late preterm data are lacking in born to HIV-infected mother. We showed that, among 202 live births, late preterm delivery was higher in born to HIV-infected mothers than in the general population while their morbidity was lower.

Determinants of morbidity in late preterm infants

OBJECTIVE

To assess the effect of selected maternal medical conditions and complications of pregnancy on the risk for morbidity among late preterm neonates.

DESIGN

Prospective cohort study.

MATERIAL AND METHODS

A total of 548 late preterm neonates (34(0/7) to 36(6/7)weeks' gestation) delivered from August 2006 to July 2009, were included. Information regarding demographics, gestational age, mode of delivery, maternal age and parity, pre-existing medical conditions and complications of pregnancy were obtained and associated with neonatal morbidity, both independently and as joint exposures. Newborn morbidity was defined by combining specific diagnoses, length of hospital stay, and transfer to the Neonatal Intensive Care Unit.

RESULTS

Overall, 165 (30.1%) of the late preterm infants suffered from morbidity. The morbidity rates were 16.8% at 36 weeks' gestation, and then approximately doubled from 38.2% at 35 weeks to 59.7% at 34 weeks. The joint effect of gestational age (OR 8.43 for 34 weeks and 3.60 for 35 weeks' gestation), small for gestational age (SGA) (OR 4.18), multiple gestation (OR 3.68) and lack of antenatal steroid administration (OR 4.03), was greater than the independent effect of each of these factors, and greater than additive. Emergency caesarean section (OR 1.43) and antepartum haemorrhage (OR 3.07) were also associated with a significant impact on neonatal morbidity.

CONCLUSIONS

The risk for morbidity among late preterm infants, changes with each passing week of gestation. This risk seems to be intensified, when other exposures such as SGA, multiple gestation, emergency caesarean section, lack of antenatal steroid administration and antepartum haemorrhage, are also present.

Preterm birth and neurodevelopmental outcome: a review

BACKGROUND

The incidence of preterm delivery and the survival rate of preterm newborns are rising, due to the increased use of assisted reproductive technology associated with multiple gestations and improved technology in obstetrics and neonatology, which allow saving preterm infants at earlier gestational ages. As a consequence, the risk of developmental disabilities in preterm children is high, and clinical pictures need to be fully defined.

METHODS

Narrative review including articles regarding neurodevelopmental disorders published in the international medical literature and reported in PubMed between the years 2000 and January 2010.

RESULTS

Although survival rates of extremely low birth weight infants (ELBW) significantly increased during the last decade, the substantial stability of disability trends in this population was disappointing. Late-preterm infants, who account for about 75% of all preterm births and had not been considered at risk for adverse long-term neurodevelopmental outcomes in the past, are now reconsidered as more likely to develop such events, though their risk remains lower than in ELBW.

CONCLUSIONS

The findings of the studies discussed in our article support the importance of early diagnosis in order to make decision about appropriate treatment of preterm infants.

Late-preterm birth, maternal symptomatology, and infant negativity

The present study examined infant negativity and maternal symptomatology by term status in a predominately low-income, rural sample of 132 infants (66 late-preterm) and their mothers. Late-preterm and term infants were group-matched by race, income, and maternal age. Maternal depression and anxiety symptoms were measured with the Brief Symptom Inventory 18 (BSI-18) when infants were 2 and 6 months of age. Also at 6 months, infant negativity was assessed by global observer ratings, maternal ratings, and microanalytic behavioral coding of fear and frustration. Results indicate that after controlling for infant age, late-preterm status predicted higher ratings of infant negativity by mothers, but not by global observers or microanalytic coding, despite a positive association in negativity across the three measures. Further, mothers of late-preterm infants reported more elevated and chronic co-morbid symptoms of depression and anxiety, which in turn, was related to concurrent maternal ratings of their infant's negativity. Mothers' response to late-preterm birth and partiality in the assessment of their infant's temperament is discussed.

Neonatal outcomes in twin pregnancies delivered moderately preterm, late preterm, and term

We compared neonatal outcomes in twin pregnancies following moderately preterm birth (MPTB), late preterm birth (LPTB), and term birth. A secondary analysis of a multicenter, randomized controlled trial of multiple gestations was conducted. MPTB was defined as delivery between 32 (0)/(7) and 33 (6)/(7) weeks and LPTB between 34 (0)/(7) and 36 (6)/(7) weeks. Primary outcome was a neonatal outcome composite consisting of one or more of the following: neonatal death, respiratory distress syndrome, early onset culture-proven sepsis, stage 2 or 3 necrotizing enterocolitis, bronchopulmonary dysplasia, grade 3 or 4 intraventricular hemorrhage, periventricular leukomalacia, pneumonia, or severe retinopathy of prematurity. Among 552 twin pregnancies, the MPTB rate was 14.5%, LPTB 49.8%, and term birth rate 35.7%. The rate of the primary outcome was different between groups: 30.0% for MPTB, 12.8% for LPTB, 0.5% for term birth ( P < 0.001). Compared with term neonates, the primary neonatal outcome composite was increased following MPTB (relative risk [RR] 58.5; 95% confidence interval [CI] 11.3 to 1693.0) and LPTB (RR 24.9; 95% CI 4.8 to 732.2). Twin pregnancies born moderately and late preterm encounter higher rates of neonatal morbidities compared with twins born at term.

Respiratory morbidity in late preterm births

CONTEXT

Late preterm births (340/7-366/7 weeks) account for an increasing proportion of prematurity-associated short-term morbidities, particularly respiratory, that require specialized care and prolonged neonatal hospital stays.

OBJECTIVE

To assess short-term respiratory morbidity in late preterm births compared with term births in a contemporary cohort of deliveries in the United States.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective collection of electronic data from 12 institutions (19 hospitals) across the United States on 233,844 deliveries between 2002 and 2008. Charts were abstracted for all neonates with respiratory compromise admitted to a neonatal intensive care unit (NICU), and late preterm births were compared with term births in regard to resuscitation, respiratory support, and respiratory diagnoses. A multivariate logistic regression analysis compared infants at each gestational week, controlling for factors that influence respiratory outcomes.

MAIN OUTCOME MEASURES

Respiratory distress syndrome, transient tachypnea of the newborn, pneumonia, respiratory failure, and standard and oscillatory ventilator support.

RESULTS

Of 19,334 late preterm births, 7055 (36.5%) were admitted to a NICU and 2032 had respiratory compromise. Of 165,993 term infants, 11,980 (7.2%) were admitted to a NICU, 1874 with respiratory morbidity. The incidence of respiratory distress syndrome was 10.5% (390/3700) for infants born at 34 weeks' gestation vs 0.3% (140/41,764) at 38 weeks. Similarly, incidence of transient tachypnea of the newborn was 6.4% (n = 236) for those born at 34 weeks vs 0.4% (n = 155) at 38 weeks, pneumonia was 1.5% (n = 55) vs 0.1% (n = 62), and respiratory failure was 1.6% (n = 61) vs 0.2% (n = 63). Standard and oscillatory ventilator support had similar patterns. Odds of respiratory distress syndrome decreased with each advancing week of gestation until 38 weeks compared with 39 to 40 weeks (adjusted odds ratio [OR] at 34 weeks, 40.1; 95% confidence interval [CI], 32.0-50.3 and at 38 weeks, 1.1; 95% CI, 0.9-1.4). At 37 weeks, odds of respiratory distress syndrome were greater than at 39 to 40 weeks (adjusted OR, 3.1; 95% CI, 2.5-3.7), but the odds at 38 weeks did not differ from 39 to 40 weeks. Similar patterns were noted for transient tachypnea of the newborn (adjusted OR at 34 weeks, 14.7; 95% CI, 11.7-18.4 and at 38 weeks, 1.0; 95% CI, 0.8-1.2), pneumonia (adjusted OR at 34 weeks, 7.6; 95% CI, 5.2-11.2 and at 38 weeks, 0.9; 95% CI, 0.6-1.2), and respiratory failure (adjusted OR at 34 weeks, 10.5; 95% CI, 6.9-16.1 and at 38 weeks, 1.4; 95% CI, 1.0-1.9).

CONCLUSION

In a contemporary cohort, late preterm birth, compared with term delivery, was associated with increased risk of respiratory distress syndrome and other respiratory morbidity.

Late preterm birth and risk of developing asthma

OBJECTIVE

To evaluate the association between gestational age at birth (late preterm vs term) and risk for physician-diagnosed asthma.

STUDY DESIGN

We conducted a retrospective cohort study using the Third National Health and Nutrition Examination Survey (1988-1994) linked natality files. The study included children age 2-83 months from singleton births, born late preterm (n=537) or term (n=5650). Using survival analysis, we modeled time to diagnosis of asthma; children with no asthma diagnosis were censored at the age of their survey interview. We used Cox proportional hazard regression to estimate hazard ratios and 95% confidence intervals for gestational age and asthma risk, adjusting for maternal age, maternal education, parental history of asthma/hay fever, maternal smoking history during pregnancy, race/ethnicity, and sex of the child.

RESULTS

Adjusted analysis showed that physician-diagnosed asthma was modestly associated with late preterm birth (hazard ratio, 1.3; 95% confidence interval, 0.8-2.0), but this association was not statistically significant (P=.30).

CONCLUSIONS

Our study found that late preterm birth was not associated with a diagnosis of asthma in early childhood.

The frequency, clinical significance, and pathological features of chronic chorioamnionitis: a lesion associated with spontaneous preterm birth

Acute chorioamnionitis is a well-established lesion of the placenta in cases with intra-amniotic infection. In contrast, the clinicopathological significance of chronic chorioamnionitis is unclear. This study was conducted to determine the frequency and severity of chronic chorioamnionitis in normal pregnancy and in various pregnancy complications. Placentas from the following patient groups were studied: (1) term not in labor (n=100), (2) term in labor (n=100), (3) preterm labor (n=100), (4) preterm prelabor rupture of membranes (n=100), (5) preeclampsia at term (n=100), (6) preterm preeclampsia (n=100), and (7) small-for-gestational-age at term (n=100). Amniotic fluid CXCL10 concentration was measured in 64 patients. CXCL9, CXCL10, and CXCL11 mRNA expressions in the chorioamniotic membranes were assessed using real-time quantitative reverse transcription-PCR. The frequency of chronic chorioamnionitis in the preterm labor group and the preterm prelabor rupture of membranes group was 34 and 39%, respectively, which was higher than that of normal-term placentas (term not in labor, 19%; term in labor, 8%; P<0.05 each). The frequency of chronic chorioamnionitis in the preeclampsia at term group, preterm preeclampsia group, and small-for-gestational-age group was 23, 16, and 13%, respectively. Concomitant villitis of unknown etiology was found in 38 and 36% of preterm labor cases and preterm prelabor rupture of membranes cases with chronic chorioamnionitis, respectively. Interestingly, the median gestational age of preterm chronic chorioamnionitis cases was higher than that of acute chorioamnionitis cases (P<0.05). The median amniotic fluid CXCL10 concentration was higher in cases with chronic chorioamnionitis than in those without, in both the preterm labor group and preterm prelabor rupture of membranes group (P<0.05 and P<0.01, respectively). CXCL9, CXCL10, and CXCL11 mRNA expression in the chorioamniotic membranes was also higher in cases with chronic chorioamnionitis than in those without chronic chorioamnionitis (P<0.05). We propose that chronic chorioamnionitis defines a common placental pathological lesion among the preterm labor and preterm prelabor rupture of membranes groups, especially in cases of late preterm birth. Its association with villitis of unknown etiology and the chemokine profile in amniotic fluid suggests an immunological origin, akin to transplantation rejection and graft-versus-host disease in the chorioamniotic membranes.

Respiratory morbidity and lung function in preterm infants of 32 to 36 weeks' gestational age

Normal lung development follows a series of orchestrated events. Premature birth interrupts normal in utero lung development, which results in significant alterations in lung function and physiology. Increasingly, there are reports documenting the broad range of complications experienced by infants aged 34 to 36 weeks' gestational age (GA). Our objective was to summarize the evidence demonstrating respiratory system vulnerability in infants aged 34 to 36 weeks' GA and to review the developmental and physiologic principles that underlie this vulnerability. A comprehensive search for studies that reported epidemiologic data and respiratory morbidity was conducted on the PubMed, Medline, Ovid Biosis, and Embase databases from 2000 to 2009 by using medical subject headings "morbidity in late preterm infants," "preterm infants and lung development," "prematurity and morbidity," and "prematurity and lung development." Because the number of studies exclusive to infants aged 34 to 36 weeks' GA was limited, selected studies also included infants aged 32 to 36 weeks' GA. Of the 24 studies identified, 16 were retrospective population-based cohort studies; 8 studies were observational. These studies consistently revealed that infants born at 32 to 36 weeks' GA, including infants of 34 to 36 weeks' GA, experience substantial respiratory morbidity compared with term infants. Levels of morbidity were, at times, comparable to those observed in very preterm infants. The developmental and physiologic mechanisms that underlie the increased morbidity rate and alterations in respiratory function are discussed. We also present evidence to demonstrate that the immaturity of the respiratory system of infants 34 to 36 weeks' GA at birth results in increased morbidity in infancy and leads to deficits in lung function that may persist into adulthood.

Neonatal outcomes of late-preterm birth associated or not with intrauterine growth restriction

Objective. To compare neonatal morbidity and mortality between late-preterm intrauterine growth-restricted (IUGR) and appropriate-for-gestational-age (AGA) infants of the comparable gestational ages (GAs). Methods. We retrospectively analyzed neonatal morbidity and mortality of 50 singleton pregnancies involving fetuses with IUGR delivered between 34 and 36 6/7 weeks of GA due to maternal and/or fetal indication. The control group consisted of 36 singleton pregnancies with spontaneous preterm delivery at the same GA, in which the infant was AGA. Categorical data were compared between IUGR and AGA pregnancies by X² analysis and Fisher's exact test. Ordinal measures were compared using the Kruskal-Wallis test. Results. The length of stay of newborns in the nursery, as well as the need for and duration of hospitalization in the neonatal intensive care unit, was longer in the group with IUGR. Transient tachypnea of the newborn or apnea rates did not differ significantly between the IUGR and AGA groups. IUGR infants were found to be at a higher risk of intraventricular hemorrhage. No respiratory distress syndrome, pulmonary hemorrhage or bronchopulmonary dysplasia was observed in either group. The frequency of sepsis, thrombocytopenia and hyperbilirubinemia was similar in the two groups. Hypoglycemia was more frequent in the IUGR group. No neonatal death was observed. Conclusion. Our study showed that late-preterm IUGR infants present a significantly higher risk of neonatal complications when compared to late-preterm AGA infants.

Role of the pediatric nurse practitioner in promoting breastfeeding for late preterm infants in primary care settings

The preterm birth rate has been increasing steadily during the past two decades. Up to two thirds of this increase has been attributed to the increasing rate of late preterm births (34 to < 37 gestational weeks). The advantages of breastfeeding for premature infants appear to be even greater than for term infants; however, establishing breastfeeding in late-preterm infants is frequently more problematic. Because of their immaturity, late preterm infants may have less stamina; difficulty with latch, suck, and swallow; temperature instability; increased vulnerability to infection; hyperbilirubinemia, and more respiratory problems than the full-term infant. Late preterm infants usually are treated as full term and discharged within 48 hours of birth, so pediatric nurse practitioners in primary care settings play a critical role in promoting breastfeeding through early assessment and detection of breastfeeding difficulties and by providing anticipatory guidance related to breastfeeding and follow-up. The purpose of this article is to describe the developmental and physiologic immaturity of late preterm infants and to highlight the role of pediatric nurse practitioners in primary care settings in supporting and promoting breastfeeding for late preterm infants.

Variation in child cognitive ability by week of gestation among healthy term births

The authors investigated variations in cognitive ability by gestational age among 13,824 children at age 6.5 years who were born at term with normal weight, using data from a prospective cohort recruited in 1996-1997 in Belarus. The mean differences in the Wechsler Abbreviated Scales of Intelligence were examined by gestational age in completed weeks and by fetal growth after controlling for maternal and family characteristics. Compared with the score for those born at 39-41 weeks, the full-scale intelligence quotient (IQ) score was 1.7 points (95% confidence interval (CI): -2.7, -0.7) lower in children born at 37 weeks and 0.4 points (95% CI: -1.1, 0.02) lower at 38 weeks after controlling for confounders. There was also a graded relation in postterm children: a 0.5-points (95% CI: -2.6, 1.6) lower score at 42 weeks and 6.0 points (95% CI: -15.1, 3.1) lower at 43 weeks. Compared with children born large for gestational age (>90th percentile), children born small for gestational age (<10th percentile) had the lowest IQ, followed by those at the 10th-50th percentile and those at the >50th-90th percentile. These findings suggest that, even among healthy children born at term, cognitive ability at age 6.5 years is lower in those born at 37 or 38 weeks and those with suboptimal fetal growth.

Maternal and fetal genetic associations of PTGER3 and PON1 with preterm birth

OBJECTIVE

The purpose of this study was to identify associations between maternal and fetal genetic variants in candidate genes and spontaneous preterm birth (PTB) in a Norwegian population and to determine the effect size of those associations that corroborate a previous study of PTB.

METHODS

DNA from 434 mother-baby dyads (214 cases and 220 controls) collected from the Norwegian Mother and Child Cohort (MoBa) was examined for association between 1,430 single nucleotide polymorphisms in 143 genes and PTB. These results were compared to a previous study on European Americans (EA) from Centennial Women's Hospital in Nashville, TN, USA. Odds ratios for SNPs that corroborated the Cenntennial study were determined on the combined MoBa and Centennial studies.

RESULTS

In maternal samples the strongest results that corroborated the Centennial study were in the prostaglandin E receptor 3 gene (PTGER3; rs977214) (combined genotype p = 3x10(-4)). The best model for rs977214 was the AG/GG genotypes relative to the AA genotype and resulted in an OR of 0.55 (95% CI = 0.37-0.82, p = 0.003), indicating a protective effect. In fetal samples the most significant association in the combined data was rs854552 in the paraoxonase 1 gene (PON1) (combined allele p = 8x10(-4)). The best model was the TT genotype relative to the CC/CT genotypes, and resulted in an OR of 1.32 (95% CI = 1.13-1.53, p = 4x10(-4)).

CONCLUSIONS

These studies identify single locus associations with preterm birth for both maternal and fetal genotypes in two populations of European ancestry.

Preterm premature rupture of membranes: clinical outcomes of late-preterm infants

OBJECTIVE

To determine gestational age-specific neonatal outcomes of late preterm infants delivered as a consequence of premature rupture of membranes (PROM).

METHODS

Retrospective cohort study of infants born to women delivered electively due to preterm PROM between 34(0/7) and 36(6/7) weeks of gestation. Neonatal outcomes were compared between those delivered at 34(0/7) to 34( 6/7) weeks, at 35(0/7) to 35(6/7) weeks, and at 36( 0/7) to 36(6/7) weeks.

RESULTS

192 infants were identified. The 34(0/7) to 34(6/7) week infants had significantly higher neonatal intensive care admission rate (72.5%) compared to those at 35( 0/7) to 35(6/7) weeks (22.8%) and at 36 to 36(6/7) weeks (17.8%) (P < .05). Neonatal respiratory distress syndrome was significantly higher at 34(0/7) to 34(6/7) weeks (35.4%) compared with 35(0/7) to 35(6/7) week and 36(0/7) to 36( 6/7) week infants (10.5% and 4.1%; P < .05). The longest hospitalization occurred in the 34(0/7) to 34(6/7) week infants (248.5 +/- 20.0 hours).

CONCLUSION

Substantial short-term morbidity occurred in late preterm infants. The greatest number of complications affected infants born at 34(0/7) to 34(6/7) weeks.

Feeding challenges in the late preterm infant

A late preterm infant is defined as one born between 34 and 36 6/7 weeks of completed gestation. The rate of late preterm births has risen 18 percent since the late 1990s. Data are beginning to emerge concerning morbidity rates and the risks these newborns face with regard to feeding difficulties, temperature instability, hypoglycemia, and hyperbilirubinemia. Feeding challenges place these vulnerable infants at risk for prolonged hospital stays and readmission after discharge. To better address the unique needs of late preterm infants, providers should establish individual feeding orders. This article offers research-based suggestions for caring for these infants in the newborn nursery and the postpartum unit as well as parent teaching guidelines.

Reconsideration of the costs of convenience: quality, operational, and fiscal strategies to minimize elective labor induction

Elective induction of labor is at an all-time high in the United States despite known associated risks. It can lead to birth of an infant too early, a long labor, exposure to a high-alert medication with its potential side effects, unnecessary cesarean birth, and maternal and neonatal morbidity. There is a cascade of interventions related to elective induction such as an intravenous line, continuous electronic fetal monitoring, confinement to bed, amniotomy, pharmacologic labor stimulating agents, parental pain medications, and regional anesthesia, each with their own set of potential complications and risk of iatrogenic harm. These risks apply to all women having the procedure, however for nulliparous women before 41 weeks of gestation with an unfavorable cervix, the main risk is cesarean birth after unsuccessful labor induction with the potential for maternal and neonatal morbidity and increased healthcare costs. When cesarean occurs, subsequent births are likely to be via cesarean as well. Elective labor induction before 41 weeks is inconsistent with quality perinatal care, and performance of this unnecessary procedure should be minimized. Convenience as the reason for labor induction is contrary to a culture focused on patient safety. A review of current evidence, followed by changes in practice, is warranted to support the safest care possible during labor and birth. Various strategies to reduce the rate of elective induction in the United States are presented.

Academic, social, and behavioral outcomes at age 12 of infants born preterm

The effects of gradient levels of perinatal morbidity on school outcomes have been investigated at age 12 in four preterm groups, classified as healthy (no medical or neurological illness), medical morbidity, neurological morbidity, and small-for-gestational-age (SGA), and a full-term comparison group. Teachers report on academic competence, social skills, and problem behaviors. Data on school type, classroom setting, and school service use are gathered from school records. Preterm groups are found to be equivalent to full-term peers in social skills and problem behavior. Preterm groups with neurological and SGA morbidity have the lowest academic competence scores. Unexpectedly, preterm infants with medical morbidity have higher academic competence scores compared with the other preterm groups. School service use increases with greater perinatal morbidity and is contingent on multiple rather than single indicators of perinatal morbidity. Continued monitoring of preterm infants through early adolescence will ensure that appropriate school services and resources are available to maximize their school success.

Early and late onset sepsis in late preterm infants

BACKGROUND

Preterm birth is increasing worldwide, and late preterm births, which comprise more than 70% of all preterm births, account for much of the increase. Early and late onset sepsis results in significant mortality in extremely preterm infants, but little is known about sepsis outcomes in late preterm infants.

METHODS

This is an observational cohort study of infants <121 days of age (119,130 infants less than or equal to 3 days of life and 106,142 infants between 4 and 120 days of life) with estimated gestational age at birth between 34 and 36 weeks, admitted to 248 neonatal intensive care units in the United States between 1996 and 2007.

RESULTS

During the study period, the cumulative incidence of early and late onset sepsis was 4.42 and 6.30 episodes per 1000 admissions, respectively. Gram-positive organisms caused the majority of early and late onset sepsis episodes. Infants with early onset sepsis caused by Gram-negative rods and infants with late onset sepsis were more likely to die than their peers with sterile blood cultures (odds ratio [OR]: 4.39, 95% CI: 1.71-11.23, P = 0.002; and OR: 3.37, 95% CI: 2.35-4.84, P < 0.001, respectively).

CONCLUSION

Late preterm infants demonstrate specific infection rates, pathogen distribution, and mortality associated with early and late onset sepsis. The results of this study are generalizable to late preterm infants admitted to the special care nursery or neonatal intensive care unit.

Visuospatial and verbal fluency relative deficits in 'complicated' late-preterm preschool children

BACKGROUND

Late-preterm children constitute a majority of all preterm deliveries (75%). Their immature brain development at birth has been associated with an increased risk for morbidities. Data have been sparse regarding neuropsychological outcomes in the preschool years.

AIM

To examine general cognition, attention/working memory, language, manual coordination/motor dexterity, visuomotor, visuospatial, and executive functions in preschoolers born late-preterm (LPT; 34-36 gestational weeks) who required NICU admission compared to term-born participants.

DESIGN

Single-center retrospective cohort study of 95 three-year-old children; 60 born LPT in 2004-2005 and admitted to the NICU compared to 35 healthy term-born participants born > or =37 gestational weeks and > or =2500 g.

RESULTS

LPT birth was associated with visuospatial (p=.005), visuomotor (p=.012), and executive function (noun [p=.018] and action-verb [p=.026] fluency) relative deficits, but not attention/working memory, receptive or expressive language, nonverbal reasoning, or manual coordination/dexterity deficit.

CONCLUSIONS

Late-preterm birth is likely to be associated with negative neuropsychological sequelae, although subtle and selective compared to effects reported for children born at an earlier gestational age. Visuospatial function appears to be especially vulnerable to disruption even at preschool age, and verbal fluency may be useful as an early predictor of executive dysfunction in childhood. Routine preschool neuropsychological evaluation is recommended to identify delay or deficit in LPT children preparing for school entry, and may highlight underlying vulnerable neural networks in LPT children.

Comparison of short-term outcomes of late preterm singletons and multiple births: an institutional experience

We compare 4 short-term outcomes--namely admission to special care nursery (SCN), length of stay (LOS), age at full feeds (AFF) and respiratory morbidity/need for ventilation--in 1015 late preterm singletons and 366 twins and triplets born at our institution over a 4-year period. Birth weight (BW) and gestational age (GA) rather than plurality of birth determined need for admission to SCN, LOS, AFF, and need for respiratory support. When matched for GA, compared to singletons, twins and triplets needed less admission to SCN and respiratory support at 36 weeks, whereas at 34 weeks, they had longer LOS and took longer to get to full feeds. We conclude that the outcomes of interest are affected by GA and BW rather than plurality.

Late preterm birth: how often is it avoidable?

OBJECTIVE

Our objective was to describe indications for late preterm birth (LPTB) and estimate the frequency of potentially avoidable LPTB deliveries.

STUDY DESIGN

Singleton pregnancies delivered between 34(0/7)-36(6/7) weeks over a 1-year period at a tertiary care medical center were studied. Indications for delivery were categorized as spontaneous (spontaneous preterm birth or premature rupture of membranes) or iatrogenic (elective or medically indicated). Potentially avoidable deliveries were defined as those with elective or medical stable, but high-risk indications.

RESULTS

During the study period there were 514 LPTB (spontaneous preterm birth 36.2%, preterm premature rupture of membranes 17.7%, medically indicated 37.9%, and elective 8.2%). Potentially avoidable LPTB accounted for 17% of LPTB and were associated with later gestational age (odds ratio [OR], 4.7; 95% confidence interval [CI], 2.5-8.6), nonfaculty physician status (OR, 2.8; 95% CI, 1.5-5.1), and prior cesarean delivery (OR, 1.5; 95% CI, 1.0-2.1).

CONCLUSION

At our institution, <10% of LPTB are purely elective and >80% are clearly unavoidable.

Outcomes of late-preterm infants: a retrospective, single-center, Canadian study

OBJECTIVE

To study the prevalence of major morbidities and mortality of inborn, late-preterm infants. Methods. A retrospective review was conducted from 2004 to 2008. Descriptive outcomes were compared with predefined aggregate outcomes of term infants during the same period.

RESULTS

Data on 1193 late-preterm and 8666 term infants were compared. Majority of late-preterm infants were 36 weeks (43.6%), followed by 35 weeks (29.2%) and 34 weeks (27.2%), respectively. The prevalence of intensive care admission, respiratory support, pneumothorax, and mortality in late preterm infants was significantly higher compared with term infants. Mechanical ventilation and continuous positive airway pressure rates substantially decreased with increased gestational age. Although only 1.0% had positive cultures, 28.5% received parenteral antibiotics. The late-preterm group had a 12-fold higher risk of death with an overall mortality rate of 0.8%.

CONCLUSION

This study confirmed the high-risk status of late-preterm infants with worse mortality and morbidities compared with term infants.

Rethinking IUGR in preeclampsia: dependent or independent of maternal hypertension?

OBJECTIVE

Chronic hypertension (CHTN) is a risk factor for both intrauterine growth restriction (IUGR) as well as preeclampsia. This study was performed to: (1) describe the prevalence of IUGR in women with preeclampsia (with and without CHTN) compared with controls, (2) investigate the relationship between preeclampsia and maternal CHTN with IUGR, and (3) investigate the relationship between IUGR and severity of preeclampsia.

STUDY DESIGN

A case-control study was performed. Cases were patients identified with preeclampsia. Controls were patients presenting for delivery at term (>or=37 weeks). IUGR prevalence by case-control status, or severity of disease was evaluated using Pearson chi(2) tests. Multivariable logistic regression was used to control for confounders.

RESULT

In all, 430 cases and 568 controls were studied. Preeclamptic women have a 2.7 (CI (1.94 to 3.86)) and 4.3 (CI (2.58 to 7.17)) times increased odds of having a fetus with IUGR at <10 and <5% compared with controls in adjusted analyses. There was a significant interaction between CHTN and IUGR. Therefore, in women without CHTN, women with PEC had increased odds of IUGR, whereas in women with CHTN, there was no difference in odds of IUGR in women with or without preeclampsia. Within the cases, severe preeclampsia was associated with IUGR<10% (AOR=1.82 (1.11 to 2.97)) but not IUGR<5% (AOR=1.6 (0.85 to 2.86)).

CONCLUSION

Preeclampsia is independently associated with the development of IUGR. As suggested earlier, women with CHTN do not have the highest prevalence of IUGR, suggesting disparate pathways by which IUGR develops in women with superimposed preeclampsia compared with preeclampsia alone.

So, he's a little premature...what's the big deal?

Health care providers have recently recognized that a large segment of the morbidity associated with preterm birth is disproportionately due to the late preterm infant (LPI). One explanation is that this population is the fastest-growing sector of all preterm births. This article describes the epidemiology and etiology of the LPI, and discusses why the LPI is at an increased risk for complications, such as thermal instability, hypoglycemia, feeding difficulties, respiratory distress, hyperbilirubinemia, and sepsis. The need for emergency department visits after hospital discharge and what is currently known regarding neurodevelopmental outcomes are also presented.

Hydration status of exclusively and partially breastfed near-term newborns in the first week of life

An in-hospital prospective, observational cohort study was conducted to assess the effects of type of feeding (exclusively breastfed [EBF] vs partially breastfed [PBF]) on the hydration status of near-term newborns in the first week of life. A total of 205 babies of 35 to 37 weeks of completed gestation were enrolled (82 in the EBF group and 123 in the PBF group). The overall incidence of significant weight loss (>or=10%) was 18% with no significant difference between EBF and PBF groups (18.3% vs 17.9%, P=.94). The incidence of hypernatremia (serum NA>or=150 meq/L) was 2.4% in the EBF group and 5.7% in the PBF group (P=.32). The factors associated with significant weight loss in the total cohort were having a mother with previous negative breastfeeding experience (adjusted odds ratio [OR]=16.5, 95% confidence interval [CI]=2.1-115.7), exposure to phototherapy (adjusted OR=9.0, 95% CI=2.5-31.8), and cesarean delivery (adjusted OR=6.7, 95% CI=2.3-19.7).

[Late preterm infants: A population at underestimated risk]

BACKGROUND AND OBJECTIVE

There has been a gradual rise in prematurity rates recent years, almost exclusively at the expense of the late preterm (34 to 36 weeks). This population, although with less risk than smaller preterm gestational age, has a morbidity rate significantly higher than term infants. However, there is some underestimation regarding developments in the short and long term. The aim of this study was to look at the incidence of prematurity in our institution and to analyze morbidity and mortality in late preterm compared with term infants

SUBJECTS AND METHODS

We performed a retrospective review of newborns in our Hospital from January 1992 until December 31, 2008. Late preterm group was defined as between 34(0/7) and 36(6/7) weeks gestation (N=2003) and term infants from 37 to 42 weeks gestation (N=32015). We formed 2 subgroups according two time periods (1992-1998 and 2000-2008). The morbidity and mortality for each of the groups and subgroups, and the morbidity from week 34 to 42, were analysed and compared.

RESULTS

During the period studied, the prematurity rate increased from 3.9% to 9.8%, exclusively at the expense of the late preterm (79%). The rate of mortality in late preterm was 5 per thousand compared to 1.1 per thousand in the term (P <0.0001, OR 4.71, 95% CI 2.3-9.5). The incidence of admission to the Neonatal Unit, Cesarean rate, twin, respiratory disorders, need for respiratory support in the form of nasal CPAP or mechanical ventilation, incidence of apnea, jaundice requiring phototherapy, hypoglycaemia and need for parenteral nutrition were significantly higher (P<0.0001) in the late preterm group compared with term infants. The morbidity rate decreased significantly as gestational age increased, with the lowest value from 39 weeks.

CONCLUSIONS

Morbidity and mortality in late preterm infants is significantly higher than in term infants. The guidelines for these near term premature babies need to be reviewed, looking for possible causes of prematurity, and trying to reduce their impact, as well as developing a protocol for their care and close monitoring to minimize the associated morbidity. There should be long-term monitoring to find out the consequences on their psychomotor development. The obstetrics group should be made aware of the true risks of births in the near-term gestational ages.

Delivery indications at late-preterm gestations and infant mortality rates in the United States

OBJECTIVE

The rate of preterm births has been increasing in the United States, especially for births 34 to 36 weeks of gestation (late preterm), which now constitute 71% of all preterm births. The causes for these trends remain unclear. We characterized the delivery indications for late preterm births and their potential impact on neonatal and infant mortality rates.

PATIENTS AND METHODS

Using the 2001 US Birth Cohort Linked birth/death files of 3 483 496 singleton births, we categorized delivery indications as follows: (1) maternal medical conditions; (2) obstetric complications; (3) major congenital anomalies; (4) isolated spontaneous labor: vaginal delivery without induction and without associated medical/obstetric factors; and (5) no recorded indication.

RESULTS

Of the 292 627 late-preterm births, the first 4 categories (those with indications and isolated spontaneous labor) accounted for 76.8%. The remaining 23.2% (67 909) were classified as deliveries with no recorded indication. Factors significantly increasing the chance of no recorded indication were older maternal age; non-Hispanic, white mother; >/=13 years of education; Southern, Midwestern, and Western region; multiparity; or previous infant with a >/=4000-g birth weight. The neonatal and infant mortality rates were significantly higher among deliveries with no recorded indication compared with deliveries secondary to isolated spontaneous labor but lower compared with deliveries with an obstetric indication or congenital anomaly.

CONCLUSIONS

A total of 23% of late preterm births had no recorded indication for delivery noted on birth certificates. Patient factors may be playing a role in these deliveries. It is concerning that these infants had higher mortality rates compared with those born after spontaneous labor at similar gestational ages. Given the excess risk of mortality, patients and providers need to discuss the risks of delivering a preterm infant in the absence of medical indications at 34 to 36 weeks.

Fatty acid patterns early after premature birth, simultaneously analysed in mothers' food, breast milk and serum phospholipids of mothers and infants

Background

The supply of long-chain polyunsaturated fatty acids via the placenta is interrupted in premature infants, making them exclusively dependent on breast milk, which varies in fatty acid (FA) concentrations depending on the mother's diet.

Objective

To in a longitudinal study explore the relation between FA status in mothers and infants from an unselected cohort of prematures, not requiring intensive care.

Design

Breast milk and mothers' and infants' plasma phospholipid FA concentrations from birth to 44 weeks of gestational age were analysed and compared with mothers' food intake, assessed using a 3-day diary. Fatty acids were analysed by capillary gas-liquid chromatography.

Results

The energy intake was low in 75% of mothers, and 90% had low intake of essential FAs (EFAs). Dietary linoleic acid (LA, 18:2w6), but not w3 FAs, correlated to concentrations in breast milk. Infants' plasma and breast milk correlated for arachidonic (AA, 20:4w6), eicosapentaenoic (EPA, 20:5w3) and docosahexaenoic (DHA, 22:6w3) acids. A high concentration of mead acid (20:3w9) in the infants at birth correlated negatively to the concentrations of LA, AA and w3 FAs. Infants of mothers who stopped breastfeeding during the study period showed decreased DHA concentrations and increased w6/w3 ratios, with the opposite FA pattern seen in the mothers' plasma.

Conclusion

Although dietary w3 FAs were insufficient in an unselected cohort of mothers of premature infants, breastfeeding resulted in increased levels of DHA in the premature infants at the expense of the mothers, suggesting a general need to increase dietary w3 FAs during pregnancy and lactation.

Neurodevelopmental outcome of the premature infant

Advances in antenatal medicine and neonatal intensive care have successfully resulted in improved survival rates of preterm infants. These improvements have been most dramatic in infants born extremely low birth weight (ELBW, <or=1000 g) and at the limits of viability (22 to 25 weeks). But improvements in survival have not been accompanied by proportional reductions in the incidence of disability in this population. Thus, survival is not an adequate measure of success in these infants who remain at high risk for neurodevelopmental and behavioral morbidities. There is now increasing evidence of sustained adverse outcomes into school age and adolescence, not only for ELBW infants but for infants born late preterm.

Health issues of the late preterm infant

"Late preterm" birth is not such an unusual occurrence; in fact these infants were the first group of premature infants who pediatricians learned to treat, and did so with such remarkable success that physicians no longer consider them to be of high risk. So, why the sudden interest in this group? There is now enough evidence that this population is not as benign as previously thought. They have increased mortality when compared to term infants and are at increased risk for complications including transient tachypnea of newborn (TTN), respiratory distress syndrome (RDS), persistent pulmonary hypertension (PPHN), respiratory failure, temperature instability, jaundice, feeding difficulties and prolonged neonatal intensive care unit (NICU) stay. Evidence is currently emerging that late preterm infants make up a majority of preterm births, take up significant resources, have increased mortality/morbidity, and may even have long-term neurodevelopmental consequences secondary to their late prematurity.

Weight for gestational age affects the mortality of late preterm infants

BACKGROUND

Late preterm infant mortality is higher than that for term newborns. The association between weight for gestational age (WGA) category and late preterm mortality has not been well described.

OBJECTIVES

Our objectives for this research were as follows: (1) to compare neonatal and infant mortality rates of SGA, AGA, and LGA late preterm, early term, and term newborns; (2) to determine the relative risk of neonatal and infant death for each WGA category; and (3) to examine causes of neonatal and infant death.

METHODS

We reviewed linked birth and death certificate data for all infants from Utah born between 1999 and 2005 with a GA > or =34 weeks. We calculated neonatal and infant mortality rates for each GA/birth weight stratum and estimated mortality rate ratios using AGA term infants as the reference. International Classification of Diseases, Ninth Revision, codes were used to classify cause of death.

RESULTS

There were 343322 newborns with GA > or =34 weeks from 1999 to 2005. Late preterm SGA infants were approximately 44 times more likely than term AGA newborns to die in their first month and 22 times more likely to die in their first year. When infants dying from congenital conditions were excluded, the differences in mortality rate ratios persisted for SGA infants, especially those born in the late preterm period.

CONCLUSIONS

Being SGA substantially increases the already higher mortality of late preterm and early term newborns. This increased risk cannot be fully explained by an increased prevalence of lethal congenital conditions among SGA late preterm newborns. Clinicians caring for late preterm and early term newborns should be cognizant of their WGA category.