A systematic review of severe morbidity in infants born late preterm

Practice variation in late-preterm deliveries: a physician survey

OBJECTIVE

Late-preterm (LPT) neonates account for over 70% of all preterm births in the US. Approximately 60% of LPT births are the result of non-spontaneous deliveries. The optimal timing of delivery for many obstetric conditions at LPT gestations is unclear, likely resulting in obstetric practice variation. The purpose of this study is to identify variation in the obstetrical management of LPT pregnancies.

STUDY DESIGN

We surveyed obstetrical providers in North Carolina identified from North Carolina Medical Board and North Carolina Obstetrical and Gynecological Society membership lists. Participants answered demographic questions and six multiple-choice vignettes on management of LPT pregnancies.

RESULT

We obtained 215/859 (29%) completed surveys which are as follows: 167 (78%) from obstetrics/gynecology, 27 (13%) from maternal-fetal medicine, and 21 (10%) from family medicine physicians. Overall, we found more agreement on respondents' management of chorioamnionitis (97% would proceed with delivery), mild pre-eclampsia (84% would delay delivery/expectantly manage) and fetal growth restriction (FGR) (80% would delay delivery/expectantly manage). We found less agreement on the management of severe preeclampsia (71% would proceed with delivery), premature preterm rupture of membranes (69% would proceed with delivery) and placenta previa (67% would delay delivery/expectantly manage). Management of LPT pregnancies complicated by preterm premature rupture of membranes, FGR and placenta previa vary by specialty.

CONCLUSION

Obstetrical providers report practice variation in the management of LPT pregnancies. Variation might be influenced by provider specialty. The absence of widespread agreement on best practice might be a source of modifiable LPT birth.

Levels of antibodies against tissue transglutaminase during pregnancy are associated with reduced fetal weight and birth weight

BACKGROUND & AIMS

Celiac disease in pregnant women has been associated with poor growth of the fetus, but little is known about how the level of celiac disease affects fetal growth or birth outcomes. We assessed the associations between levels of antibodies against tissue transglutaminase (anti-tTG, a marker of celiac disease) and fetal growth and birth outcomes for pregnant women.

METHODS

We performed a population-based prospective birth cohort study of 7046 pregnant women. Serum samples were collected during the second trimester of pregnancy and analyzed for levels of anti-tTG. Based on these levels, the women were categorized into 3 groups: negative anti-tTG (≤0.79 U/mL; n = 6702), intermediate anti-tTG (0.8 to ≤6 U/mL; n = 308), or positive anti-tTG (>6 U/mL; n = 36). Data on fetal growth and birth outcomes were collected from ultrasound measurements and medical records.

RESULTS

Fetuses of women in the positive anti-tTG group weighed 16 g less than those of women in the negative anti-tTG group (95% confidence interval [CI], -32 to -1 g) during the second trimester and weighed 74 g less (95% CI, -140 to -8 g) during the third trimester. Newborns of women in the intermediate and positive anti-tTG groups weighed 53 g (95% CI, -106 to -1 g) and 159 g (95% CI, -316 to -1 g) less at birth, respectively, than those of women in the negative anti-tTG group. The reduction in birth weight in offspring of mothers in the intermediate anti-tTG group was 2-fold greater among mothers who carried HLA-DQ2 or -DQ8 than among those without HLA-DQ2 or -DQ8.

CONCLUSIONS

Levels of anti-tTG in pregnant women are inversely associated with fetal growth. Growth was reduced to the greatest extent in fetuses of women with the highest levels of anti-tTG (>6 U/mL). Birth weight was also reduced in women with intermediate levels of anti-tTG (0.8 to ≤6 U/mL) and further reduced in those carrying HLA-DQ2 and -DQ8.

Low birth weight and very low birth weight neonates with congenital heart disease: timing of surgery, reasons for delaying or not delaying surgery

Conventional management of low birth weight and very low birth weight neonates was composed of deferring corrective surgery by aggressive medical management or palliative surgery which does not require cardiopulmonary bypass. However, while waiting for weight gain, these neonates are at risk for various comorbidities. In the current era, this "wait and let the baby grow" approach has not been shown to result in better clinical outcomes. Early primary repair hence has become the standard strategy for congenital heart disease requiring surgery in these neonates. However, there still exist some circumstances, which are considered to be unfavorable for corrective surgery due to medical, physiologic, surgeon's technical and institutional-systemic factors. We reviewed the recent literature and examined the reasons for delaying or not delaying surgery.

Postnatal catch-up fat after late preterm birth

BACKGROUND

Late preterm birth accounts for 70% of preterm births. The aim of the study was to investigate the postnatal weight gain and weight gain composition changes in a cohort of late preterm infants.

METHODS

A total of 49 late preterm infants (mean birth weight 2,496 ± 330 g and gestational age 35.2 ± 0.7 wks) underwent growth and body composition assessment by an air displacement plethysmography system on the fifth day of life, at term, and at 1 and 3 mo of corrected age. The reference group was composed of 40 healthy, full-term, breast-fed infants.

RESULTS

The late preterm infants showed a Δ fat mass gain between birth and term-corrected age equal to 182%. As compared with full-term infants, at term and 1 mo of corrected age mean weight (3,396 ± 390 vs. 3,074 ± 409 g and 4,521 ± 398 vs. 4,235 ± 673 g, respectively) and percentage of fat mass (16.1 ± 4.6 vs. 8.9 ± 2.9 and 22.6 ± 4.2 vs. 17.4 ± 4.0, respectively) were significantly higher in late preterm infants, whereas no difference among groups was found at 3 mo.

CONCLUSION

Rapid postnatal catch-up fat was found in these infants. Further studies are needed to investigate whether this short-term increase in fat mass may modulate the risk of chronic diseases or represent an adaptive mechanism to extrauterine life.

Neonatal stabilization and postresuscitation care

Neonatal mortality is a major health care concern worldwide. Neonatal resuscitation alone does not address most causes of neonatal mortality; caregivers need to be trained in both neonatal resuscitation and stabilization. Neonatal stabilization requires caregivers to evaluate whether babies are at-risk or unwell, to decide what interventions are required, and to act on those decisions. Several programs address neonatal stabilization in a variety of levels of care in both well-resourced and limited health care environments. This article suggests a shift in clinical, educational, and implementation science from a focus on resuscitation to one on the resuscitation-stabilization continuum.

Performance of an automatic quantitative ultrasound analysis of the fetal lung to predict fetal lung maturity

OBJECTIVE

The objective of the study was to evaluate the performance of automatic quantitative ultrasound analysis (AQUA) texture extractor to predict fetal lung maturity tests in amniotic fluid.

STUDY DESIGN

Singleton pregnancies (24.0-41.0 weeks) undergoing amniocentesis to assess fetal lung maturity (TDx fetal lung maturity assay [FLM]) were included. A manual-delineated box was placed in the lung area of a 4-chamber view of the fetal thorax. AQUA transformed the information into a set of descriptors. Genetic algorithms extracted the most relevant descriptors and then created and validated a model that could distinguish between mature or immature fetal lungs using TDx-FLM as a reference.

RESULTS

Gestational age at enrollment was (mean [SD]) 32.2 (4.5) weeks. According to the TDx-FLM results, 41 samples were mature and 62 were not. The imaging biomarker based on AQUA presented a sensitivity 95.1%, specificity 85.7%, and an accuracy 90.3% to predict a mature or immature lung.

CONCLUSION

Fetal lung ultrasound textures extracted by AQUA provided robust features to predict TDx-FLM results.

A common problem for neonatal intensive care units: late preterm infants, a prospective study with term controls in a large perinatal center

Compared with term infants, late preterm infants are immature physiologically and metabolically, and have higher risks for medical complications such as respiratory distress, hypoglycemia, hyperbilirubinemia, sepsis, feeding difficulty and poor neurodevelopmental outcomes. The incidence of late preterm birth is increasing. We evaluated the clinical and demographic characteristics, short-term outcomes and clinical courses of late preterm infants admitted to our neonatal intensive care unit (NICU). Data from NICU admissions of 605 late preterm and 1477 term infants in the 1-year period between June 2010 and May 2011 were analyzed. There were 2004 late preterm deliveries and 18,854 total deliveries. Of late preterm infants, 30% were admitted to the NICU. The mean gestational age and birth weight were 35(1/7) weeks and 2352 g, respectively. The admission diagnoses were respiratory distress (46.5%), low birth weight (17.5%), jaundice (13.7%), feeding difficulty (13.1%), polycythemia (8.1%) and hypoglycemia (4%); these morbidity rates were higher than those in term infants (p < 0.001). The overall mean hospitalization period was 7.5 ± 9.1 days. The respective mortality and rehospitalization rates were 2.1% and 4.4%, which were higher than those for term infants (p < 0.001). In conclusion, late preterm infants should be followed closely for the complications just after birth, and preventive strategies should be developed.

Risks associated with delivering infants 2 to 6 weeks before term--a review of recent data

BACKGROUND

There is an increasing trend towards delivery before 39 weeks of gestational age. The short- and long-term effects of early delivery on the infant have only recently received scientific attention.

METHODS

Selective review of the literature

RESULTS

Delivery at any time before 39 weeks is associated with significantly higher infant mortality and with an increase of the risk of impairments after birth from 8% to 11%. The increase in risks of various kinds is disproportionately more pronounced the earlier the child is delivered. For example, the risk of needing respiratory support or artificial ventilation after birth increases from 0.3% with delivery at 39-41 weeks of gestational age to 1.4% at 37 weeks and 10% at 35 weeks, while the risk of death or neurological complications increases from 0.15% at 39-41 weeks of gestation to 0.66% at 35 weeks. Delivery at 34.0 to 36.6 weeks of gestation also has long-term effects. Compared to delivery at term, the frequency of cerebral palsy rises threefold, from 0.14% to 0.43%; the risk of death in early adulthood rises by about half, from 0.046 to 0.065%; and the risk of dependence on government benefits in early adulthood also rises by about half, from 1.7% to 2.5%.

CONCLUSION

Studies from the USA have shown that the number of medically indicated deliveries before 39 weeks can be lowered by 70% to 80% through consistently applied measures for quality improvement. If similar results could be achieved in Germany, the iatrogenic complications of delivery would become less common in this country as well.

Neonatology and the caesarean section

The origins of the use of the Caesarean section date far back in human history. Traces of this procedure can be found in Greek mythology and in the history of Ancient Rome. Many documents about the history of religion make reference to a delivery from the abdomen.

Trends in planned early birth: a population-based study

OBJECTIVE

The purpose of this study was to describe trends and outcomes of planned births.

STUDY DESIGN

Data from linked birth and hospital records for 779,521 singleton births at ≥33 weeks' gestation from 2001-2009 were used to determine trends in planned births (prelabor cesarean section and labor inductions). Adverse outcomes were composite indicators of maternal and neonatal morbidity/death.

RESULTS

From 2001-2009, there were increases in labor inductions and prelabor cesarean deliveries at <40 weeks' gestation, but no decrease in the stillbirth rate (trend P = .34). By 2009, 14.9% of live births at ≥33 weeks' gestation were prelabor cesarean deliveries before the due date; 11.4% were inductions. As planned births increased, maternal risks shifted, which included a decline in inductions with maternal hypertension from 31.9-23.9%. Earlier birth was contemporaneous with increases (trend P < .001) in neonatal and maternal morbidity rates from 3.0-3.2% and 1.1-1.5%, respectively.

CONCLUSION

Planned birth before the due date is increasing without a contemporaneous reduction of stillbirths.

Late preterm birth: a review of medical and neuropsychological childhood outcomes

Late preterm (LP) birth (34 0/7 - 36 6/7 weeks' gestation) accounts for nearly three-fourths of all preterm births, making this population a sizeable public health concern. The immature fetal development associated with LP delivery increases the risk of mortality and short-term medical complications. Which combination of maternal, fetal, or neonatal risk factors may be most critical has only recently begun to be addressed, and whether LP birth's disruptive impact on brain development will exert adverse effects on neuropsychological functioning in childhood and adolescence has been understudied. Early data have shown a graded response, with LP children often functioning better than very preterm children but worse than term children, and with subtle intellectual and neuropsychological deficits in LP children compared with healthy children born at term gestational age. Further characterization of the neuropsychological profile is required and would be best accomplished through prospective longitudinal studies. Moreover, since moderate and LP births result in disparate medical and psychological outcomes, the common methodology of combining these participants into a single research cohort to assess risk and outcome should be reconsidered. The rapidly growing LP outcomes literature reinforces a critical principle: fetal development occurs along a dynamic maturational continuum from conception to birth, with each successive gestational day likely to improve overall outcome.

National, regional, and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications

BACKGROUND

Preterm birth is the second largest direct cause of child deaths in children younger than 5 years. Yet, data regarding preterm birth (<37 completed weeks of gestation) are not routinely collected by UN agencies, and no systematic country estimates nor time trend analyses have been done. We report worldwide, regional, and national estimates of preterm birth rates for 184 countries in 2010 with time trends for selected countries, and provide a quantitative assessment of the uncertainty surrounding these estimates.

METHODS

We assessed various data sources according to prespecified inclusion criteria. National Registries (563 datapoints, 51 countries), Reproductive Health Surveys (13 datapoints, eight countries), and studies identified through systematic searches and unpublished data (162 datapoints, 40 countries) were included. 55 countries submitted additional data during WHO's country consultation process. For 13 countries with adequate quality and quantity of data, we estimated preterm birth rates using country-level loess regression for 2010. For 171 countries, two regional multilevel statistical models were developed to estimate preterm birth rates for 2010. We estimated time trends from 1990 to 2010 for 65 countries with reliable time trend data and more than 10,000 livebirths per year. We calculated uncertainty ranges for all countries.

FINDINGS

In 2010, an estimated 14·9 million babies (uncertainty range 12·3-18·1 million) were born preterm, 11·1% of all livebirths worldwide, ranging from about 5% in several European countries to 18% in some African countries. More than 60% of preterm babies were born in south Asia and sub-Saharan Africa, where 52% of the global livebirths occur. Preterm birth also affects rich countries, for example, USA has high rates and is one of the ten countries with the highest numbers of preterm births. Of the 65 countries with estimated time trends, only three (Croatia, Ecuador, and Estonia), had reduced preterm birth rates 1990-2010.

INTERPRETATION

The burden of preterm birth is substantial and is increasing in those regions with reliable data. Improved recording of all pregnancy outcomes and standard application of preterm definitions is important. We recommend the addition of a data-quality indicator of the per cent of all live preterm births that are under 28 weeks' gestation. Distinguishing preterm births that are spontaneous from those that are provider-initiated is important to monitor trends associated with increased caesarean sections. Rapid scale up of basic interventions could accelerate progress towards Millennium Development Goal 4 for child survival and beyond.

FUNDING

Bill & Melinda Gates Foundation through grants to Child Health Epidemiology Reference Group (CHERG) and Save the Children's Saving Newborn Lives programme; March of Dimes; the Partnership for Maternal Newborn and Childe Health; and WHO, Department of Reproductive Health and Research.