Fetal and neonatal outcomes of preterm infants born before 32 weeks of gestation according to antenatal vs postnatal assessments of restricted growth

Association between Endotype of Prematurity and Mortality: A Systematic Review, Meta-Analysis, and Meta-Regression

INTRODUCTION

Preterm birth represents the leading cause of neonatal mortality. Pathophysiological pathways, or endotypes, leading to prematurity can be clustered into infection/inflammation and dysfunctional placentation. We aimed to perform a systematic review and meta-analysis exploring the association between these endotypes and risk of mortality during first hospital admission Methods: PROSPERO ID: CRD42020184843. PubMed and Embase were searched for observational studies examining infants with gestational age (GA) ≤34 weeks. Chorioamnionitis represented the infectious-inflammatory endotype, while dysfunctional placentation proxies were hypertensive disorders of pregnancy (HDP) and small for GA (SGA)/intrauterine growth restriction (IUGR). A random-effects model was used to calculate odds ratios (ORs) and 95% confidence intervals. Heterogeneity was studied using random-effects meta-regression analysis.

RESULTS

Of 4,322 potentially relevant studies, 150 (612,580 infants) were included. Meta-analysis showed positive mortality odds for chorioamnionitis (OR: 1.43, 95% confidence interval: 1.25-1.62) and SGA/IUGR (OR: 1.68, 95% confidence interval: 1.38-2.04) but negative mortality odds for HDP (OR 0.74, 95% confidence interval: 0.64-0.86). Chorioamnionitis was associated with a lower GA, while HDP and SGA/IUGR were associated with a higher GA. Meta-regression showed a significant correlation between these differences in GA and mortality odds.

CONCLUSION

Our data suggest that the infectious/inflammatory endotype of prematurity has a greater overall impact on mortality risk as it is the most frequent endotype in the lower GAs. However, when the endotype of placental dysfunction is severe enough to induce growth restriction, it is strongly associated with higher mortality rates even though newborns are more mature.

[Medical termination of pregnancy for isolated intrauterine growth retardation beyond 24 weeks and more than 450g]

INTRODUCTION

Fetal growth restriction (FGR) is an obstetric complication responsible for increased perinatal morbidity and mortality. In some severe and early FGR situations, termination of pregnancy (TOP) may be considered. The main objective of our study was to describe the population of fetuses for whom a TOP was performed for isolated FGR beyond 24 days' gestation and for a birth weight>450g and to analyze the immediate outcome, at 2 and 5 years, of term- and weight-matched neonates born in a context of severe FGR after 24 weeks' gestation and over 450g.

MATERIAL AND METHODS

We conducted an observational, descriptive, retrospective, uni-centric study between 2008 and 2018. The primary endpoint was survival at maternity discharge, 2 years and 5 years in these children. Secondary endpoints were assessment of immediate and longer-term postnatal morbidity. Twenty-five patients (36%) were selected for the study with a fetus weight>450g and term>24 weeks. Each fetus with an TOP was matched (on gestational age and weight) with two live-born children from the perinatal network cohort to assess immediate discharge outcome, and then at 2 and 5 years.

RESULTS

The mortality rate was 24%. In neonatal management, for 67% (n=17) of the newborns the evolution was complicated by death or at least two sequelae (bronchopulmonary dysplasia, hyaline membrane disease stage≥2, intraventricular of grade 3 and 4, ulcerative colitis requiring surgery, retinopathy of prematurity stage 2 and more) at discharge. In 32% (n=8) of cases, there was at least one sequela at discharge. Regardless of gestational age at birth, development at 2 years was normal for 48% (n=11/23) of them and abnormal for 22% (n=5) and development at 5 years was normal for 56% (n=9/16) of them and abnormal for 19% (n=5).

CONCLUSION

An ultrasound evaluation in a reference center as well as additional information by the obstetrician and neonatologist ensures the most appropriate informed involvement of the couple in the medical decisions before and after birth.

Diagnostic Tests in the Prediction of Neonatal Outcome in Early Placental Fetal Growth Restriction

Background and Objectives: Monitoring pregnancies with fetal growth restriction (FGR) presents a challenge, especially concerning the time of delivery in cases of early preterm pregnancies below 32 weeks. The aim of our study was to compare different diagnostic parameters in growth-restricted preterm neonates with and without morbidity/mortality and to determine sensitivity and specificity of diagnostic parameters for monitoring preterm pregnancies with early preterm fetal growth restriction below 32 weeks. Materials and Methods: Our clinical study evaluated 120 cases of early preterm deliveries, with gestational age ≤ 32 + 0 weeks, with prenatally diagnosed placental FGR. All the patients were divided into three groups of 40 cases each based on neonatal condition,: I-Neonates with morbidity/mortality (NMM); II-Neonates without morbidity with acidosis/asphyxia (NAA); III-Neonates without neonatal morbidity/acidosis/asphyxia (NWMAA). Results: Amniotic fluid index (AFI) was lower in NMM, while NWMAA had higher biophysical profile scores (BPS). UA PI was lower in NWMAA. NWMAA had higher MCA PI and CPR and fewer cases with CPR <5th percentile. NMM had higher DV PI, and more often had ductus venosus (DV) PI > 95th‱ or absent/reversed A wave, and pulsatile blood flow in umbilical vein (UV). The incidence of pathological fetal heart rate monitoring (FHRM) was higher in NMM and NAA, although the difference was not statistically significant. ROC calculated by defining a bad outcome as NMM and a good outcome as NAA and NWMAA showed the best sensitivity in DV PIi. ROC calculated by defined bad outcome in NMM and NAA and good outcome in NWMAA showed the best sensitivity in MCA PI. Conclusions: In early fetal growth restriction normal cerebral blood flow strongly predicts good outcomes, while pathological venous blood flow is associated with bad outcomes. In fetal growth restriction before 32 weeks, individualized expectant management remains the best option for the optimal timing of delivery.

Bronchopulmonary Dysplasia in Extremely Premature Infants: A Scoping Review for Identifying Risk Factors

BACKGROUND

Over the years, bronchopulmonary dysplasia (BPD) affects the pulmonary function of infants, resulting in chronic health burdens for infants and their families. The aim of this scoping review was to screen available evidence regarding perinatal risk factors associated with the development and severity of BPD.

METHODS

The eligibility criteria of the studies were year of publication between 2016 and 2021; setting of a developed country; English or Japanese as the study language; and randomized controlled, cohort, or case-control design. The titles and abstracts of the studies were screened by independent reviewers.

RESULTS

Of 8189 eligible studies, 3 were included for severe BPD and 26 were included for moderate BPD. The risk factors for severe BPD were male sex, iatrogenic preterm birth, maternal hypertensive disorders of pregnancy (HDP), low gestational age, small-for-gestational-age (SGA) birth weight, mechanical ventilation on day 1, and need for patent ductus arteriosus (PDA) management. The risk factors for moderate or severe BPD included male sex, premature rupture of membranes, clinical chorioamnionitis, maternal HDP, SGA birth weight, bubbly/cystic appearance on X-ray, and PDA management.

CONCLUSIONS

We identified several risk factors for BPD. We plan to confirm the validity of the new classification using the existing dataset.

Severity of small-for-gestational-age and morbidity and mortality among very preterm neonates

OBJECTIVE

Evaluate the association between small for gestational age (SGA) severity and morbidity and mortality in a contemporary, population of very preterm infants.

STUDY DESIGN

This secondary analysis of a California statewide database evaluated singleton infants born during 2008-2018 at 24-32 weeks' gestation, with a birthweight <15th percentile. We analyzed neonatal outcomes in relation to weight for gestational age (WGA) and symmetry of growth restriction.

RESULTS

An increase in WGA by one z-score was associated with decreased major morbidity or mortality risk (aRR 0.73, 95% CI 0.68-0.77) and other adverse outcomes. The association was maintained across gestational ages and did not differ by fetal growth restriction diagnosis. Symmetric growth restriction was not associated with neonatal outcomes after standardizing for gestational age at birth.

CONCLUSIONS

Increasing SGA severity had a significant impact on neonatal outcomes among very preterm infants.

Non-reassuring fetal status and anesthetic impact on cesarean section-delivered very-low-birthweight infants

BACKGROUND

There is limited evidence concerning the impact on neonatal outcomes of different types of anesthesia used for cesarean delivery due to non-reassuring fetal status (NRFS). We aimed to assess the impact of NRFS and general anesthesia (GA) on neonatal outcomes in very-low-birthweight (VLBW) infants delivered by cesarean section.

METHODS

Data were collected relating to VLBW infants admitted to our institution. Infants were grouped into no-NRFS and NRFS groups and further subcategorized into GA and regional anesthesia (RA) subgroups. Neonatal outcomes were evaluated based on the presence of NRFS and the type of anesthesia.

RESULTS

A total of 356 infants were included. The GA subgroup in the no-NRFS group had higher requirements for respiratory support. However, GA was not associated with adverse neonatal outcomes based on the multivariable logistic regression analysis except for 5 min Apgar score <5. On the other hand, NRFS was associated with an increased risk of 5 min Apgar score <5 [adjusted odds ratio (aOR) 2.062, 95% confidence interval (CI) 1.064-3.997], use of high-frequency ventilation (aOR: 2.891, 95% CI: 1.477-5.658), and pulmonary hypertension (aOR: 2.890, 95% CI: 1.436-5.819).

CONCLUSIONS

In our cohort of VLBW infants, NRFS was a significant risk factor for a low 5 min Apgar score, increased respiratory support requirement, and pulmonary hypertension. Accurate assessment of fetal well-being, timely delivery, and presence of a resuscitation team fully aware of perinatal conditions and anesthetic impact is important.

Fetal growth restriction: underdiagnosed condition with non-optimal screening

BACKGROUND

Fetal Growth restriction (FGR) is the pathological failure of a fetus to reach its biologically determined growth potential. Detection of FGR fetuses is a universally agreed key objective of antenatal care. Antenatal detection of FGR has undeniable benefits, juggling between intensive fetal surveillance and optimized timing of delivery; it reduces adverse perinatal outcomes by up to four-fold. However, FGR is still widely underdiagnosed. We aimed to identify the prevalence of FGR diagnosis in our wards and study the impact of the 2013 published French guidelines on the detection rate of FGR. The secondary objective aimed to highlight the factors of suboptimal screening in the population of non-diagnosed FGR fetuses and emphasize the screening method that led to antenatal diagnosis of FGR.

MATERIALS AND METHODS

We conducted a retrospective study at a single tertiary maternity center in Lyon-France, the Femme Mère Enfant Hospital, including the exhaustive population of FGR born after 24 + 0 weeks of gestation from 1 January 2011 to 31 December 2017. FGR was defined combining the neonatal and antenatal consensus-based definitions for early and late FGR in absence of congenital anomalies, excluding small for gestational age fetuses. For all FGR fetuses, we compared the antenatal detection rate of FGR during 2011-2013 to 2015-2017, since the French guidelines were published in December 2013. When FGR fetuses underwent an antenatal diagnosis of FGR, we retrospectively collected the characteristics that led to the diagnosis. When fetuses were not diagnosed as FGR, we retrospectively reviewed the implementation of the recommended screening method, enabling to evaluate whether screening was optimal or not. Statistical analysis was performed in July 2018, and statistical significance was regarded as a p-value <.05.

RESULTS

Over the seven-year period, and among 31,052 newborns, 1020 (3.3%) infants were identified as FGR and met the inclusion criteria. The detection rate of FGR was similar before and after publication of the French Guidelines related to FGR in 2013. Indeed, 50.8% (201/395) FGR were diagnosed between 2011 and 2013 versus 52.6% (245/465) between 2015 and 2017 (p = .59). In the population of non-diagnosed FGR infants, screening was suboptimal in 80%. Symphysis-fundal height (SFH) was not measured in 10.7%, with no difference before and after 2014 (7.3 versus 11.8% p = .11). Ultrasound examination for fetal biometry had not been prescribed in spite of abnormal SFH in 47.7% of undiagnosed FGR infants. Diagnosis has been missed in 11.5% of infants because of misinterpretation of the estimated fetal weight's centile.

CONCLUSION

FGR is widely underdiagnosed. However, the limited performances can partially be explained by the regular misuse of screening method in clinical practice. Despite the systematic third trimester ultrasound screening, the detection rate of FGR was similar to the one reported in the medical literature. The timing of routine third trimester ultrasound in low-risk women may be rethought.

Association of the dysfunctional placentation endotype of prematurity with bronchopulmonary dysplasia: a systematic review, meta-analysis and meta-regression

Background

Antenatal pathological conditions are key in the pathogenesis of bronchopulmonary dysplasia (BPD). Pathophysiological pathways or endotypes leading to prematurity and perinatal lung injury can be clustered into two groups: infection and dysfunctional placentation, which include hypertensive disorders of pregnancy (HDP) and intrauterine growth restriction (IUGR). We conducted a systematic review of observational studies exploring the association between the dysfunctional placentation endotype and BPD.

Methods

MEDLINE, Embase and Web of Science databases were searched up to February 2020 for studies reporting data on the diagnosis of HDP, IUGR or small for gestational age (SGA) and BPD risk. BPD was classified as BPD28 (supplemental oxygen on day 28), BPD36 (oxygen at 36 weeks postmenstrual age), severe BPD (≥ 30% oxygen or mechanical ventilation), BPD36/death and BPD-associated pulmonary hypertension.

Results

Of 6319 studies screened, 211 (347 963 infants) were included. Meta-analysis showed an association between SGA/IUGR and BPD36 (OR 1.56, 95% CI 1.37 to 1.79), severe BPD (OR 1.82, 95% CI 1.36 to 2.29) and BPD/death (OR 1.91, 95% CI 1.55 to 2.37). Exposure to HDP was not associated with BPD but was associated with decreased odds of BPD/death (OR 0.77, 95% CI 0.64 to 0.94). Both HDP (OR 1.41, 95% CI 1.10 to 1.80) and SGA/IUGR (OR 2.37, 95% CI 1.86 to 3.02) were associated with BPD-associated pulmonary hypertension.

Conclusion

When placental vascular dysfunction is accompanied by fetal growth restriction or being born SGA, it is associated with an increased risk of developing BPD and pulmonary hypertension. The placental dysfunction endotype of prematurity is strongly associated with the vascular phenotype of BPD.

Prospero registration number

Review protocol was registered in PROSPERO database (ID=CRD42018086877).

Parents' ratings of post-discharge healthcare for their children born very preterm and their suggestions for improvement: a European cohort study

BACKGROUND

Follow-up of very preterm infants is essential for reducing risks of health and developmental problems and relies on parental engagement. We investigated parents' perceptions of post-discharge healthcare for their children born very preterm in a European multi-country cohort study.

METHODS

Data come from a 5-year follow-up of an area-based cohort of births <32 weeks' gestation in 19 regions from 11 European countries. Perinatal data were collected from medical records and 5-year data from parent-report questionnaires. Parents rated post-discharge care related to their children's preterm birth (poor/fair/good/excellent) and provided free-text suggestions for improvements. We analyzed sociodemographic and medical factors associated with poor/fair ratings, using inverse probability weights to adjust for attrition bias, and assessed free-text responses using thematic analysis.

RESULTS

Questionnaires were returned for 3635 children (53.8% response rate). Care was rated as poor/fair for 14.2% [from 6.1% (France) to 31.6% (Denmark)]; rates were higher when children had health or developmental problems (e.g. cerebral palsy (34.4%) or epilepsy (36.9%)). From 971 responses, 4 themes and 25 subthemes concerning care improvement were identified.

CONCLUSIONS

Parents' experiences provide guidance for improving very preterm children's post-discharge care; this is a priority for children with health and developmental problems as parental dissatisfaction was high.

IMPACT

In a European population-based very preterm birth cohort, parents rated post-discharge healthcare as poor or fair for 14.2% of children, with a wide variation (6.1-31.6%) between countries. Dissatisfaction was reported in over one-third of cases when children had health or developmental difficulties, such as epilepsy or cerebral palsy. Parents' free-text suggestions for improving preterm-related post-discharge healthcare were similar across countries; these focused primarily on better communication with parents and better coordination of care. Parents' lived experiences are a valuable resource for understanding where care improvements are needed and should be included in future research.

Cause of preterm birth and late-onset sepsis in very preterm infants: the EPIPAGE-2 cohort study

BACKGROUND

The pathogenesis of late-onset sepsis (LOS) in preterm infants is poorly understood and knowledge about risk factors, especially prenatal risk factors, is limited. This study aimed to assess the association between the cause of preterm birth and LOS in very preterm infants.

METHODS

2052 very preterm singletons from a national population-based cohort study alive at 72 h of life were included. Survival without LOS was compared by cause of preterm birth using survival analysis and Cox regression models.

RESULTS

437 (20.1%) had at least one episode of LOS. The frequency of LOS varied by cause of preterm birth: 17.1% for infants born after preterm labor, 17.9% after preterm premature rupture of membranes, 20.3% after a placental abruption, 20.3% after isolated hypertensive disorders, 27.5% after hypertensive disorders with fetal growth restriction (FGR), and 29.4% after isolated FGR. In multivariate analysis, when compared to infants born after preterm labor, the risk remained higher for infants born after hypertensive disorders (hazard ratio HR = 1.7, 95% CI = 1.2-2.5), hypertensive disorders with FGR (HR = 2.6, 95% CI = 1.9-3.6) and isolated FGR (HR = 2.9, 95% CI = 1.9-4.4).

CONCLUSION

Very preterm infants born after hypertensive disorders or born after FGR had an increased risk of LOS compared to those born after preterm labor.

IMPACT

Late-onset sepsis risk differs according to the cause of preterm birth. Compared with those born after preterm labor, infants born very preterm because of hypertensive disorders of pregnancy and/or fetal growth restriction display an increased risk for late-onset sepsis. Antenatal factors, in particular the full spectrum of causes leading to preterm birth, should be taken into consideration to better prevent and manage neonatal infectious morbidity and inform the parents.

Small for Gestational Age Preterm Neonates Exhibit Defective GH/IGF1 Signaling Pathway

Objective: To investigate the impact of fetal growth restriction (FGR) on hormonal regulation of post-natal growth and glucose metabolism [via insulin and growth hormone (GH)/Insulin-like Growth factor 1 (IGF1) axis pathways] in small for gestational age (SGA) neonates. Methods: We conducted a monocentric observational prospective comparative study on 73 singleton babies born with a weight inferior to 2,000 g. We analyzed auxological (weight, height and head circumference), and hormonal (GH, IGF1, and insulin plasma concentrations) data comparing SGA and appropriate for gestational age (AGA) neonates, between day 1 and 60. Results: One third (23/73) of the neonates were SGA. Twenty-five percent (18/73) required insulin for idiopathic hyperglycemia of prematurity and were smaller in weight and head circumference at discharge. In the SGA group compared with the AGA group, GH plasma concentrations were higher at day 3 (70.1 vs. 38.0 mIU/L) and IGF1 plasma concentrations were higher at day 10 (29.0 vs. 18.7 ng/ml). Conclusions: SGA neonates displayed resistance to GH and IGF1, concomitant to insulin resistance. This could partially explain the initial defective catch-up growth and, later in life, the higher prevalence of metabolic syndrome in this population.

Society for Maternal-Fetal Medicine Consult Series #52: Diagnosis and management of fetal growth restriction: (Replaces Clinical Guideline Number 3, April 2012)

Fetal growth restriction can result from a variety of maternal, fetal, and placental conditions. It occurs in up to 10% of pregnancies and is a leading cause of infant morbidity and mortality. This complex obstetrical problem has disparate published diagnostic criteria, relatively low detection rates, and limited preventative and treatment options. The purpose of this Consult is to outline an evidence-based, standardized approach for the prenatal diagnosis and management of fetal growth restriction. The recommendations of the Society for Maternal-Fetal Medicine are as follows: (1) we recommend that fetal growth restriction be defined as an ultrasonographic estimated fetal weight or abdominal circumference below the 10th percentile for gestational age (GRADE 1B); (2) we recommend the use of population-based fetal growth references (such as Hadlock) in determining fetal weight percentiles (GRADE 1B); (3) we recommend against the use of low-molecular-weight heparin for the sole indication of prevention of recurrent fetal growth restriction (GRADE 1B); (4) we recommend against the use of sildenafil or activity restriction for in utero treatment of fetal growth restriction (GRADE 1B); (5) we recommend that a detailed obstetrical ultrasound examination (current procedural terminology code 76811) be performed with early-onset fetal growth restriction (<32 weeks of gestation) (GRADE 1B); (6) we recommend that women be offered fetal diagnostic testing, including chromosomal microarray analysis, when fetal growth restriction is detected and a fetal malformation, polyhydramnios, or both are also present regardless of gestational age (GRADE 1B); (7) we recommend that pregnant women be offered prenatal diagnostic testing with chromosomal microarray analysis when unexplained isolated fetal growth restriction is diagnosed at <32 weeks of gestation (GRADE 1C); (8) we recommend against screening for toxoplasmosis, rubella, or herpes in pregnancies with fetal growth restriction in the absence of other risk factors and recommend polymerase chain reaction for cytomegalovirus in women with unexplained fetal growth restriction who elect diagnostic testing with amniocentesis (GRADE 1C); (9) we recommend that once fetal growth restriction is diagnosed, serial umbilical artery Doppler assessment should be performed to assess for deterioration (GRADE 1C); (10) with decreased end-diastolic velocity (ie, flow ratios greater than the 95th percentile) or in pregnancies with severe fetal growth restriction (estimated fetal weight less than the third percentile), we suggest weekly umbilical artery Doppler evaluation (GRADE 2C); (11) we recommend Doppler assessment up to 2-3 times per week when umbilical artery absent end-diastolic velocity is detected (GRADE 1C); (12) in the setting of reversed end-diastolic velocity, we suggest hospitalization, administration of antenatal corticosteroids, heightened surveillance with cardiotocography at least 1-2 times per day, and consideration of delivery depending on the entire clinical picture and results of additional evaluation of fetal well-being (GRADE 2C); (13) we suggest that Doppler assessment of the ductus venosus, middle cerebral artery, or uterine artery not be used for routine clinical management of early- or late-onset fetal growth restriction (GRADE 2B); (14) we suggest weekly cardiotocography testing after viability for fetal growth restriction without absent/reversed end-diastolic velocity and that the frequency be increased when fetal growth restriction is complicated by absent/reversed end-diastolic velocity or other comorbidities or risk factors (GRADE 2C); (15) we recommend delivery at 37 weeks of gestation in pregnancies with fetal growth restriction and an umbilical artery Doppler waveform with decreased diastolic flow but without absent/reversed end-diastolic velocity or with severe fetal growth restriction with estimated fetal weight less than the third percentile (GRADE 1B); (16) we recommend delivery at 33-34 weeks of gestation for pregnancies with fetal growth restriction and absent end-diastolic velocity (GRADE 1B); (17) we recommend delivery at 30-32 weeks of gestation for pregnancies with fetal growth restriction and reversed end-diastolic velocity (GRADE 1B); (18) we suggest delivery at 38-39 weeks of gestation with fetal growth restriction when the estimated fetal weight is between the 3rd and 10th percentile and the umbilical artery Doppler is normal (GRADE 2C); (19) we suggest that for pregnancies with fetal growth restriction complicated by absent/reversed end-diastolic velocity, cesarean delivery should be considered based on the entire clinical scenario (GRADE 2C); (20) we recommend the use of antenatal corticosteroids if delivery is anticipated before 33 6/7 weeks of gestation or for pregnancies between 34 0/7 and 36 6/7 weeks of gestation in women without contraindications who are at risk of preterm delivery within 7 days and who have not received a prior course of antenatal corticosteroids (GRADE 1A); and (21) we recommend intrapartum magnesium sulfate for fetal and neonatal neuroprotection for women with pregnancies that are <32 weeks of gestation (GRADE 1A).

Pregnancy-specific transcriptional changes upon endotoxin exposure in mice

Objectives Pregnant women are more susceptible to certain infections; however, this increased susceptibility is not fully understood. Herein, systems biology approaches were utilized to elucidate how pregnancy modulates tissue-specific host responses to a bacterial product, endotoxin. Methods Pregnant and non-pregnant mice were injected with endotoxin or saline on 16.5 days post coitum (n=8-11 per group). The uterus, cervix, liver, adrenal gland, kidney, lung, and brain were collected 12 h after injection and transcriptomes were measured using microarrays. Heatmaps and principal component analysis were used for visualization. Differentially expressed genes between groups were assessed using linear models that included interaction terms to determine whether the effect of infection differed with pregnancy status. Pathway analysis was conducted to interpret gene expression changes. Results We report herein a multi-organ atlas of the transcript perturbations in pregnant and non-pregnant mice in response to endotoxin. Pregnancy strongly modified the host responses to endotoxin in the uterus, cervix, and liver. In contrast, pregnancy had a milder effect on the host response to endotoxin in the adrenal gland, lung, and kidney. However, pregnancy did not drastically affect the host response to endotoxin in the brain. Conclusions Pregnancy imprints organ-specific host immune responses upon endotoxin exposure. These findings provide insight into the host-response against microbes during pregnancy.

Small for gestational age very preterm infants present a higher risk of developing bronchopulmonary dysplasia

INTRODUCTION

Several studies assessed the influence of a low birth weight on bronchopulmonary dysplasia (BPD), but not all could find a significant association. Our aim was to assess the association between low birth weight and BPD in preterm infants, prospectively recruited at 11 level III Portuguese neonatal centers.

METHODS

Obstetrical and neonatal data on mothers and preterm infants with gestational ages between 24 and 30 weeks, born during 2015 and 2016 after a surveilled pregnancy, were analyzed. Neonates were considered small for gestational age (SGA) when their birthweight was below the 10th centile of Fenton's growth chats and BPD was defined as the dependency for oxygen therapy until 36 weeks of corrected age. Statistical analysis was performed using IBM SPSS® statistics 23 and a p-value <0.05 was considered statistically significant.

RESULTS

Out of 614, a total of 494 preterm infants delivered from 410 women were enrolled in the study; 40 (8.0%) infants with SGA criteria. SGA were more often associated with a single pregnancy, had greater use of antenatal corticosteroids, increased prevalence of gestational hypertensive disorders, C-section, rupture of membranes below 18 hours, rate of intubation in the delivery room, use of surfactant treatment, oxygen therapy, mechanical ventilation need, BPD, cystic periventricular leukomalacia, nosocomial sepsis and pneumonia; had lower prevalence of chorioamnionitis, and lower Apgar scores. The multivariate analysis by logistic regression, adjusted for BPD risk factors revealed a significant association between SGA and BPD: OR = 5.2 [CI: 1.46-18.58]; p = 0.01.

CONCLUSION

The results of this study increase the scientific evidence that SGA is an independent risk factor for BPD.

HSP70: an alarmin that does not induce high rates of preterm birth but does cause adverse neonatal outcomes

Objective: Preterm labor and birth are strongly associated with sterile intra-amniotic inflammation, a clinical condition that is proposed to be initiated by danger signals, or alarmins. The aim of this study was to investigate whether the intra-amniotic administration of the alarmin heat shock protein 70 (HSP70) induces preterm labor/birth and adverse neonatal outcomes.Methods: Pregnant mice received an intra-amniotic injection of 200 ng (n = 8), 400 ng (n = 6), 500 ng (n = 10), or 1 µg of HSP70 (n = 6). Control mice were injected with saline (n = 10). Following injection, the rates of preterm labor/birth and neonatal mortality were recorded. Neonatal weights at weeks 1, 2, and 3 were also recorded.Results: The intra-amniotic injection of 400 ng [late preterm birth 16.7 ± 16.7% (1/6)], 500 ng [early and late preterm birth 10 ± 10% (1/10) each], or 1 µg [early preterm birth 16.7 ± 16.7% (1/6)] of HSP70 induced low rates of preterm/birth. However, the intra-amniotic injection of 500 ng or 1 µg of HSP70 induced significantly higher rates of neonatal mortality compared to controls [saline 14.2% (10/74), 200 ng 9.8% (6/61), 400 ng 17.9% (9/45), 500 ng 28.8% (23/78), and 1 µg 21.4% (13/49)]. Neonates born to dams injected with 200, 500 ng, or 1 µg HSP70 were leaner than controls (p ≤ .05).Conclusion: Intra-amniotic administration of the alarmin HSP70 did not induce high rates of preterm labor/birth; yet, it did indeed result in adverse neonatal outcomes.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

Ultrasound measurement of fetal abdominal subcutaneous tissue thickness as a predictor of large versus small fetuses for gestational age

Background

Commonly used ultrasound fetal weight estimation formulas show variable degrees of error which is more evident in fetuses with nutritional and metabolic issues; better accuracy of fetal weight estimation can be obtained by incorporation of fetal soft tissue parameters like the fetal subcutaneous tissue in the weight estimation process. The aim of this study was to assess the accuracy of fetal abdominal subcutaneous tissue thickness (FASTT) as an indicator of fetal birth weight.

Results

FASTT showed a high significant statistical correlation with fetal birth weight (r = 0.94, P value = 0.00); it showed higher sensitivity for large for gestational age (LGA) than small for gestational age (SGA) (90.9% and 86.9%, respectively). The best cutoff value for the detection of LGA was ≥ 9.2 mm and ≤ 4.5 for SGA. FASTT showed lower accuracy than abdominal circumference (AC) as an indicator of LGA (92% versus 96%, respectively). Used alone, FASTT is less sensitive than Hadlock formula in both LGA and SGA (90.9% versus 94.5% in LGA and 86.9% versus 88.9% for SGA, respectively). There was no statistical correlation between FASTT and mode of delivery (r = 0.09, P value = 0.23) nor fetal gender (r = 0.15, P value = 0.11)

Conclusion

FASTT is a good indicator of fetal birth weight especially LGA, yet it is less sensitive than AC in the prediction of LGA. It cannot be used as a predictor of mode of delivery and not affected by fetal gender.

Fetal T Cell Activation in the Amniotic Cavity during Preterm Labor: A Potential Mechanism for a Subset of Idiopathic Preterm Birth

Prematurity is the leading cause of perinatal morbidity and mortality worldwide. In most cases, preterm birth is preceded by spontaneous preterm labor, a syndrome that is associated with intra-amniotic inflammation, the most studied etiology. However, the remaining etiologies of preterm labor are poorly understood; therefore, most preterm births are categorized as idiopathic. In this study, we provide evidence showing that the fetal immune system undergoes premature activation in women with preterm labor without intra-amniotic inflammation, providing a potential new mechanism of disease for some cases of idiopathic preterm birth. First, we showed that fetal T cells are a predominant leukocyte population in amniotic fluid during preterm gestations. Interestingly, only fetal CD4+ T cells were increased in amniotic fluid of women who underwent idiopathic preterm labor and birth. This increase in fetal CD4+ T cells was accompanied by elevated amniotic fluid concentrations of T cell cytokines such as IL-2, IL-4, and IL-13, which are produced by these cells upon in vitro stimulation, but was not associated with the prototypical cytokine profile observed in women with intra-amniotic inflammation. Also, we found that cord blood T cells, mainly CD4+ T cells, obtained from women with idiopathic preterm labor and birth displayed enhanced ex vivo activation, which is similar to that observed in women with intra-amniotic inflammation. Finally, we showed that the intra-amniotic administration of activated neonatal CD4+ T cells induces preterm birth in mice. Collectively, these findings provide evidence suggesting that fetal T cell activation is implicated in the pathogenesis of idiopathic preterm labor and birth.

Cellular immune responses in amniotic fluid of women with preterm labor and intra-amniotic infection or intra-amniotic inflammation

PROBLEM

Preterm birth is commonly preceded by preterm labor, a syndrome that is causally linked to both intra-amniotic infection and intra-amniotic inflammation. However, the stereotypical cellular immune responses in these two clinical conditions are poorly understood.

METHOD OF STUDY

Amniotic fluid samples (n = 26) were collected from women diagnosed with preterm labor and intra-amniotic infection (amniotic fluid IL-6 concentrations ≥2.6 ng/mL and culturable microorganisms, n = 10) or intra-amniotic inflammation (amniotic fluid IL-6 concentrations ≥2.6 ng/mL without culturable microorganisms, n = 16). Flow cytometry was performed to evaluate the phenotype and number of amniotic fluid leukocytes. Amniotic fluid concentrations of classical pro-inflammatory cytokines, type 1 and type 2 cytokines, and T-cell chemokines were determined using immunoassays.

RESULTS

Women with spontaneous preterm labor and intra-amniotic infection had (a) a greater number of total leukocytes, including neutrophils and monocytes/macrophages, in amniotic fluid; (b) a higher number of total T cells and CD4⁺ T cells, but not CD8⁺ T cells or B cells, in amniotic fluid; and (c) increased amniotic fluid concentrations of IL-6, IL-1β, and IL-10, compared to those with intra-amniotic inflammation. However, no differences in amniotic fluid concentrations of T-cell cytokines and chemokines were observed between these two clinical conditions.

CONCLUSION

The cellular immune responses observed in women with preterm labor and intra-amniotic infection are more severe than in those with intra-amniotic inflammation, and neutrophils, monocytes/macrophages, and CD4⁺ T cells are the main immune cells responding to microorganisms that invade the amniotic cavity. These findings provide insights into the intra-amniotic immune mechanisms underlying the human syndrome of preterm labor.

Obstetric and pediatric growth charts for the detection of fetal growth restriction and neonatal adverse outcomes in preterm newborns before 34 weeks of gestation

INTRODUCTION

Identification of fetal growth-restricted (FGR) infants depends on the fetal or newborn charts used to identify them. We aimed to compare the prenatal and postnatal diagnosis of FGR and their ability to predict adverse perinatal outcomes.

METHODS

Observational retrospective cohort study of 95 consecutive mother-infant pairs with preterm birth between 24 and 34 weeks (study period: January 2014 to December 2015). Prenatal sonographic diagnosis of FGR, based on customized fetal growth standards and fetal Doppler, was compared with the postnatal diagnosis of FGR based on a birthweight < 3rd percentile according to newborn charts (International Newborn size references for the Intergrowth twenty-first century program, and Olsen's charts). Neonatal mortality and adverse neonatal outcomes were compared among groups.

RESULTS

In 23/95 (24%) cases a prenatal diagnosis of early FGR was made. Postnatal FGR was confirmed in 11/23 (48%) cases using Olsen's charts and 8/23 (35%) using Intergrowth 21st charts. One postnatal FGR case was missed by prenatal ultrasound. Bronchopulmonary dysplasia, sepsis and hypoglycemia were more frequent in pre- and postnatal FGR versus non-FGR. After adjusting for gestational age and sex, only an increased relative risk of hypoglycemia (2.0, 95%CI 1.0-2.8) was observed in infants with pre- and postnatal FGR diagnosis. Nonsignificant differences on neonatal outcomes were identified between prenatal FGR cases with normal birthweight and the non-FGR group.

CONCLUSION

Only prenatal FGR cases in which a birthweight below the third percentile is confirmed by means of postnatal charts (Olsen or Intergrowth standard) are at higher risk of adverse postnatal outcome.

The Possible Role of Placental Morphometry in the Detection of Fetal Growth Restriction

Fetal growth restriction (FGR) is often the result of placental insufficiency and is characterized by insufficient transplacental transport of nutrients and oxygen. The main underlying entities of placental insufficiency, the pathophysiologic mechanism, can broadly be divided into impairments in blood flow and exchange capacity over the syncytiovascular membranes of the fetal placenta villi. Fetal growth restriction is not synonymous with small for gestational age and techniques to distinguish between both are needed. Placental insufficiency has significant associations with adverse pregnancy outcomes (perinatal mortality and morbidity). Even in apparently healthy survivors, altered fetal programming may lead to long-term neurodevelopmental and metabolic effects. Although the concept of fetal growth restriction is well appreciated in contemporary obstetrics, the appropriate detection of FGR remains an issue in clinical practice. Several approaches have aimed to improve detection, e.g., uniform definition of FGR, use of Doppler ultrasound profiles and use of growth trajectories by ultrasound fetal biometry. However, the role of placental morphometry (placental dimensions/shape and weight) deserves further exploration. This review article covers the clinical relevance of placental morphometry during pregnancy and at birth to help recognize fetuses who are growth restricted. The assessment has wide intra- and interindividual variability with various consequences. Previous studies have shown that a small placental surface area and low placental weight are associated with a slower growth of the fetus. Parameters such as placental surface area, placental volume and placental weight in relation to birth weight can help to identify FGR. In the future, a model including sophisticated antenatal placental morphometry may prove to be a clinically useful method for screening or diagnosing growth restricted fetuses, in order to provide optimal monitoring.

Neonatal Morbidities of Fetal Growth Restriction: Pathophysiology and Impact

Being born small lays the foundation for short-term and long-term implications for life. Intrauterine or fetal growth restriction describes the pregnancy complication of pathological reduced fetal growth, leading to significant perinatal mortality and morbidity, and subsequent long-term deficits. Placental insufficiency is the principal cause of FGR, which in turn underlies a chronic undersupply of oxygen and nutrients to the fetus. The neonatal morbidities associated with FGR depend on the timing of onset of placental dysfunction and growth restriction, its severity, and the gestation at birth of the infant. In this review, we explore the pathophysiological mechanisms involved in the development of major neonatal morbidities in FGR, and their impact on the health of the infant. Fetal cardiovascular adaptation and altered organ development during gestation are principal contributors to postnatal consequences of FGR. Clinical presentation, diagnostic tools and management strategies of neonatal morbidities are presented. We also present information on the current status of targeted therapies. A better understanding of neonatal morbidities associated with FGR will enable early neonatal detection, monitoring and management of potential adverse outcomes in the newborn period and beyond.

Intrauterine Growth Restriction and Patent Ductus Arteriosus in Very and Extremely Preterm Infants: A Systematic Review and Meta-Analysis

It is generally accepted that intrauterine growth restriction (IUGR) increases morbidity and mortality among very preterm neonates. However, evidence is hampered by the widespread practice of using the terms small for gestational age (SGA) and IUGR as synonyms. We conducted a systematic review of studies reporting on the association between IUGR/SGA and patent ductus arteriosus (PDA). PubMed/MEDLINE and EMBASE databases were searched. Of 993 studies reviewed, 47 (50,790 infants) were included. Studies were combined using a random effects model and sources of heterogeneity were determined by subgroup and meta-regression analyses. Meta-analysis of all included studies showed a significantly reduced risk of PDA in the SGA/IUGR group with an odds ratio (OR) of 0.82, and a 95% confidence interval (CI) of 0.70 to 0.96 (p = 0.015). Of the 47 studies, only 7 used a definition for growth restriction that went beyond birth weight (BW) for gestational age (GA). When pooled, meta-analysis could not demonstrate a significant effect size (OR 1.31, 95% CI 0.75 to 2.27, p = 0.343). Moreover, the significantly reduced risk of PDA was found in the 25 studies defining SGA as BW <10th percentile (OR 0.81, 95% CI 0.66 to 0.98, p = 0.032), but not in the 6 studies defining SGA as BW <3rd (OR 1.09, 95% CI 0.70 to 1.71, p = 0.694), or in the 27 studies using a more refined definition of PDA (i.e., hemodynamically significant PDA or PDA requiring treatment, OR 0.87, 95% CI 0.72 to 1.04, p = 0.133). In addition, we found that GA was significantly higher in the SGA/IUGR group (18 studies, mean difference 0.63 weeks, 95% CI 0.24 to 1.03, p = 0.002). Meta-regression analysis confirmed the correlation between this difference in GA and PDA risk. In summary, we observed marked heterogeneity across studies in the definition of growth restriction and PDA, and we found differences between the control and growth-restricted groups in relevant baseline characteristics, such as GA. Therefore, our meta-analysis could not provide conclusive evidence on the association between growth restriction and PDA.

Acute Kidney Injury in Pregnancy: The Need for Higher Awareness. A Pragmatic Review Focused on What Could Be Improved in the Prevention and Care of Pregnancy-Related AKI, in the Year Dedicated to Women and Kidney Diseases

Pregnancy-related acute kidney injury (pAKI), preeclampsia (PE), and the hypertensive disorders of pregnancy are closely related conditions, which are, in turn, frequently linked to pre-existing and often non-diagnosed chronic kidney disease (CKD). The current literature and research mainly underline the effects of pregnancy complications on the offspring; this review strongly emphasizes the maternal health as well. These conditions not only negatively affect pregnancy outcomes, but have a relevant effect on the future health of affected mothers and their children. Therefore, dedicated diagnostic and follow-up programs are needed, for optimizing materno-foetal health and reducing the impact of pregnancy-related problems in the mothers and in the new generations. This narrative review, performed on the occasion of the 2018 World Kidney Day dedicated to women’s health, focuses on three aspects of the problem. Firstly, the risk of AKI in the hypertensive disorders of pregnancy (the risk is the highest in developing countries; however PE is the main cause of pregnancy related AKI worldwide). Secondly, the effect of AKI and the hypertensive disorders of pregnancy on the development of CKD in the mother and offspring: long-term risks are increased; the entity and the trajectories are still unknown. Thirdly, the role of CKD in the pathogenesis of AKI and the hypertensive disorders of pregnancy: CKD is a major risk factor and the most important element in the differential diagnosis; pregnancy is a precious occasion for early diagnosis of CKD. Higher awareness on the importance of AKI in pregnancy is needed to improve short and long term outcomes in mothers and children.

Innate lymphoid cells at the human maternal-fetal interface in spontaneous preterm labor

PROBLEM

Pathological inflammation is causally linked to preterm labor and birth, the leading cause of neonatal morbidity and mortality worldwide. Our aims were to investigate whether (i) the newly described family of innate lymphoid cells (ILCs) was present at the human maternal-fetal interface and (ii) ILC inflammatory subsets were associated with the pathological process of preterm labor.

METHODS OF STUDY

Decidual leukocytes were isolated from women with preterm or term labor as well as from gestational age-matched non-labor controls. ILCs (CD15- CD14- CD3- CD19- CD56- CD11b- CD127+ cells) and their subsets (ILC1, T-bet+ ILCs; ILC2, GATA3+ ILCs; and ILC3, RORγt+ ILCs) and cytokine expression were identified in the decidual tissues using immunophenotyping.

RESULTS

(i) The proportion of total ILCs was increased in the decidua parietalis of women with preterm labor; (ii) ILC1s were a minor subset of decidual ILCs during preterm and term gestations; (iii) ILC2s were the most abundant ILC subset in the decidua during preterm and term gestations; (iv) the proportion of ILC2s was increased in the decidua basalis of women with preterm labor; (v) the proportion of ILC3s was increased in the decidua parietalis of women with preterm labor; and (vi) during preterm labor, ILC3s had higher expression of IL-22, IL-17A, IL-13, and IFN-γ compared to ILC2s in the decidua.

CONCLUSION

ILC2s were the most abundant ILC subset at the human maternal-fetal interface during preterm and term gestations. Yet, during preterm labor, an increase in ILC2s and ILC3s was observed in the decidua basalis and decidua parietalis, respectively. These findings provide evidence demonstrating a role for ILCs at the maternal-fetal interface during the pathological process of preterm labor.

Planning management and delivery of the growth-restricted fetus

A uniform approach to management of fetal growth restriction (FGR) improves outcome, prevents stillbirth, and allows appropriately timed delivery. An estimated fetal weight below the tenth percentile with coexisting abnormal umbilical artery (UA), middle cerebral artery (MCA), or cerebroplacental ratio Doppler index best identifies the small fetus requiring surveillance. Placental perfusion defects are more common earlier in gestation; accordingly, early-onset (≤32 weeks of gestation) and late-onset (>32 weeks) FGR differ in clinical phenotype. In early-onset FGR, progression of UA Doppler abnormality determines clinical acceleration, while abnormal ductus venosus (DV) Doppler precedes deterioration of biophysical variables and stillbirth. Accordingly, late DV Doppler changes, abnormal biophysical variables, or an abnormal cCTG require delivery. In late-onset FGR, MCA Doppler abnormalities precede deterioration and stillbirth. However, from 34 to 38 weeks, randomized evidence on optimal delivery timing is lacking. From 38 weeks onward, the balance of neonatal versus fetal risks favors delivery.

Risk of fetal death in growth-restricted fetuses with umbilical and/or ductus venosus absent or reversed end-diastolic velocities before 34 weeks of gestation: a systematic review and meta-analysis

OBJECTIVE

The objective of the study was to establish the risk of fetal death in early-onset growth-restricted fetuses with absent or reversed end-diastolic velocities in the umbilical artery or ductus venosus.

DATA SOURCES

A systematic search was performed to identify relevant studies published in English, Spanish, French, Italian, or German using the databases PubMed, ISI Web of Science, and SCOPUS, without publication time restrictions.

STUDY ELIGIBILITY CRITERIA

The study criteria included observational cohort studies and randomized controlled trials of early-onset growth-restricted fetuses (diagnosed before 34 weeks of gestation), with information on the rate of fetal death occurring before 34 weeks of gestation and absent or reversed end-diastolic velocities in the umbilical artery and/or ductus venosus.

STUDY APPRAISAL AND SYNTHESIS METHODS

For quality assessment, 2 reviewers independently assessed the risk of bias using the Newcastle-Ottawa Scale for observational studies and the Cochrane Collaboration's tool for randomized trials. For the meta-analysis, odds ratio for both fixed and random-effects models (weighting by inverse of variance) were used. Heterogeneity between studies was assessed using tau², χ2 (Cochrane Q), and I² statistics. Publication bias was assessed by a funnel plot for meta-analyses and quantified by the Egger method.

RESULTS

A total of 31 studies were included in this meta-analysis. The odds ratios for fetal death (random-effects models) were 3.59 (95% confidence interval, 2.3-5.6), 7.27 (95% confidence interval, 4.6-11.4), and 11.6 (95% confidence interval, 6.3-19.7) for growth-restricted fetuses with umbilical artery absent end-diastolic velocities, umbilical artery reversed end-diastolic velocities, and ductus venosus absent or reversed end-diastolic velocities, respectively. There was no substantial heterogeneity among studies for any of the analyses.

CONCLUSION

Early-onset growth-restricted fetuses with either umbilical artery or ductus venosus absent or reserved end-diastolic velocities are at a substantially increased risk for fetal death.

Individualized growth assessment: conceptual framework and practical implementation for the evaluation of fetal growth and neonatal growth outcome

Fetal growth abnormalities can pose significant consequences on perinatal morbidity and mortality of nonanomalous fetuses. The most widely accepted definition of fetal growth restriction is an estimated fetal weight less than the 10th percentile for gestational age according to population-based criteria. However, these criteria do not account for the growth potential of an individual fetus, nor do they effectively separate constitutionally small fetuses from ones that are malnourished. Furthermore, conventional approaches typically evaluate estimated fetal weight at a single time point, rather than using serial scans, to evaluate growth. This article provides a conceptual framework for the individualized growth assessment of a fetus/neonate based on measuring second-trimester growth velocity of fetal size parameters to estimate growth potential. These estimates specify size models that generate individualized third-trimester size trajectories and predict birth characteristics. Comparisons of measured and predicted values are used to separate normally growing fetuses from those with growth abnormalities. This can be accomplished with individual anatomical parameters or sets of parameters. A practical and freely available software (Individualized Growth Assessment Program) has been developed to allow implementation of this approach for clinical and research purposes.