Fecal microbiota and volatile metabolome pattern alterations precede late-onset meningitis in preterm neonates

OBJECTIVE

The fecal microbiota and metabolome are hypothesized to be altered before late-onset neonatal meningitis (LOM), in analogy to late-onset sepsis (LOS). The present study aimed to identify fecal microbiota composition and volatile metabolomics preceding LOM.

METHODS

Cases and gestational age-matched controls were selected from a prospective, longitudinal preterm cohort study (born <30 weeks' gestation) at nine neonatal intensive care units. The microbial composition (16S rRNA sequencing) and volatile metabolome (gas chromatography-ion mobility spectrometry (GC-IMS) and GC-time-of-flight-mass spectrometry (GC-TOF-MS)), were analyzed in fecal samples 1-10 days pre-LOM.

RESULTS

Of 1397 included infants, 21 were diagnosed with LOM (1.5%), and 19 with concomitant LOS (90%). Random Forest classification and MaAsLin2 analysis found similar microbiota features contribute to the discrimination of fecal pre-LOM samples versus controls. A Random Forest model based on six microbiota features accurately predicts LOM 1-3 days before diagnosis with an area under the curve (AUC) of 0.88 (n=147). Pattern recognition analysis by GC-IMS revealed an AUC of 0.70-0.76 (P<0.05) in the three days pre-LOM (n=92). No single discriminative metabolites were identified by GC-TOF-MS (n=66).

CONCLUSION

Infants with LOM could be accurately discriminated from controls based on preclinical microbiota composition, while alterations in the volatile metabolome were moderately associated with preclinical LOM.

Associations between Bronchopulmonary Dysplasia, Insulin-like Growth Factor I and Nutrition

Insulin-like growth factor I (IGF-I) has been suggested as an important factor in the pathogenesis of bronchopulmonary dysplasia (BPD). In turn, nutrition has been associated with IGF-I levels and could be of importance in the pathogenesis of BPD. This study aimed to explore the association between nutrition, the IGF-I axis and the occurrence of BPD. Eighty-six preterm infants (44 male, mean gestational age: 29.0 weeks (standard deviation: 1.7 weeks)) were enrolled in an observational study. Serum IGF-I (µg/L) and insulin-like growth factor binding protein 3 (IGFBP-3; mg/L) were measured at birth and at 2, 4 and 6 weeks postnatal age. BPD was diagnosed at 36 weeks postmenstrual age. Twenty-nine infants were diagnosed with BPD. For every µg/L per week increase in IGF-I, the odds of BPD decreased (0.68, 95% CI 0.48-0.96, corrected for gestational age). The change in IGF-I in µg/L/week, gestational age in weeks and a week of predominant donor human milk feeding were associated with the occurrence of BPD in the multivariable analysis (respectively, OR 0.63 (0.43-0.92), OR 0.44 (0.26-0.76) and 7.6 (1.2-50.4)). IGFBP-3 was not associated with the occurrence of BPD in the multivariable analysis. In conclusion, a slow increase in IGF-I levels and a lower gestational age increase the odds of BPD. Donor human milk might increase the odds of BPD and should be further explored.

Identifying effect modifiers of systemic hydrocortisone treatment initiated 7-14 days after birth in ventilated very preterm infants on long-term outcome: secondary analysis of a randomised controlled trial

OBJECTIVE

To explore clinical effect modifiers of systemic hydrocortisone in ventilated very preterm infants for survival and neurodevelopmental outcome at 2 years' corrected age (CA).

DESIGN

Secondary analysis of a randomised placebo-controlled trial.

SETTING

Dutch and Belgian neonatal intensive care units.

PATIENTS

Infants born <30 weeks' gestational age (GA), ventilator-dependent in the second week of postnatal life.

INTERVENTION

Infants were randomly assigned to systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190).

MAIN OUTCOME MEASURES

The composite of death or neurodevelopmental impairment (NDI) at 2 years' CA and its components. Candidate effect modifiers (GA, small for GA, respiratory index, sex, multiple births, risk of moderate/severe bronchopulmonary dysplasia or death) were analysed using regression models with interaction terms and subpopulation treatment effect pattern plots.

RESULTS

The composite outcome was available in 356 (96.0%) of 371 patients (one consent withdrawn). For this outcome, treatment effect heterogeneity was seen across GA subgroups (<27 weeks: hydrocortisone (n=141) vs placebo (n=156), 54.6% vs 66.2%; OR 0.61 (95% CI 0.38 to 0.98); ≥27 weeks: hydrocortisone (n=30) vs placebo (n=31), 66.7% vs 45.2%; OR 2.43 (95% CI 0.86 to 6.85); p=0.02 for interaction). This effect was also found for the component death (<27 weeks: 20.1% vs 32.1%; OR 0.53 (95% CI 0.32 to 0.90); ≥27 weeks: 28.1% vs 16.1%; OR 2.04 (95% CI 0.60 to 6.95); p=0.049 for interaction) but not for the component NDI. No differential treatment effects were observed across other subgroups.

CONCLUSION

This secondary analysis suggests that in infants <27 weeks' GA, systemic hydrocortisone may improve the outcome death or NDI, mainly driven by its component death. There was insufficient evidence for other selected candidate effect modifiers.

Doxapram versus placebo in preterm newborns: a study protocol for an international double blinded multicentre randomized controlled trial (DOXA-trial)

BACKGROUND

Apnoea of prematurity (AOP) is one of the most common diagnoses among preterm infants. AOP often leads to hypoxemia and bradycardia which are associated with an increased risk of death or disability. In addition to caffeine therapy and non-invasive respiratory support, doxapram might be used to reduce hypoxemic episodes and the need for invasive mechanical ventilation in preterm infants, thereby possibly improving their long-term outcome. However, high-quality trials on doxapram are lacking. The DOXA-trial therefore aims to investigate the safety and efficacy of doxapram compared to placebo in reducing the composite outcome of death or severe disability at 18 to 24 months corrected age.

METHODS

The DOXA-trial is a double blinded, multicentre, randomized, placebo-controlled trial conducted in the Netherlands, Belgium and Canada. A total of 396 preterm infants with a gestational age below 29 weeks, suffering from AOP unresponsive to non-invasive respiratory support and caffeine will be randomized to receive doxapram therapy or placebo. The primary outcome is death or severe disability, defined as cognitive delay, cerebral palsy, severe hearing loss, or bilateral blindness, at 18-24 months corrected age. Secondary outcomes are short-term neonatal morbidity, including duration of mechanical ventilation, bronchopulmonary dysplasia and necrotising enterocolitis, hospital mortality, adverse effects, pharmacokinetics and cost-effectiveness. Analysis will be on an intention-to-treat principle.

DISCUSSION

Doxapram has the potential to improve neonatal outcomes by improving respiration, but the safety concerns need to be weighed against the potential risks of invasive mechanical ventilation. It is unknown if the use of doxapram improves the long-term outcome. This forms the clinical equipoise of the current trial. This international, multicentre trial will provide the needed high-quality evidence on the efficacy and safety of doxapram in the treatment of AOP in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04430790 and EUDRACT 2019-003666-41. Prospectively registered on respectively June and January 2020.

Time to first passage of meconium and defecation frequency preceding necrotizing enterocolitis in preterm infants: a case-control study

Necrotizing enterocolitis (NEC) is associated with significant morbidity and mortality in preterm infants. Early recognition and treatment of NEC are critical to improving outcomes. Enteric nervous system (ENS) immaturity has been proposed as a key factor in NEC pathophysiology. Gastrointestinal dysmotility is associated with ENS immaturity and may serve as a predictive factor for the development of NEC. In this case-control study, preterm infants (gestational age (GA) < 30 weeks) were included in two level-IV neonatal intensive care units. Infants with NEC in the first month of life were 1:3 matched to controls based on GA (± 3 days). Odds ratios for NEC development were analyzed by logistic regression for time to first passage of meconium (TFPM), duration of meconial stool, and mean daily defecation frequency over the 72 h preceding clinical NEC onset (DF < T0). A total of 39 NEC cases and 117 matched controls (median GA 27 + 4 weeks) were included. Median TFPM was comparable in cases and controls (36 h [IQR 13-65] vs. 30 h [IQR 9-66], p = 0.83). In 21% of both cases and controls, TFPM was ≥ 72 h (p = 0.87). Duration of meconial stool and DF < T0 were comparable in the NEC and control group (median 4 and 3, resp. in both groups). Odds of NEC were not significantly associated with TFPM, duration of meconial stools, and DF < T0 (adjusted odds ratio [95% confidence interval]: 1.00 [0.99-1.03], 1.16 [0.86-1.55] and 0.97 [0.72-1.31], resp.).

CONCLUSION

In this cohort, no association was found between TFPM, duration of meconium stool, and DF < T0 and the development of NEC.

WHAT IS KNOWN

• Necrotizing enterocolitis (NEC) is a life-threatening acute intestinal inflammatory disease of the young preterm infant. Early clinical risk factors for NEC have been investigated in order to facilitate early diagnosis and treatment. • Signs of disrupted gastrointestinal mobility, such as gastric retention and paralytic ileus, have been established to support the diagnosis of NEC. Nevertheless, defecation patterns have insufficiently been studied in relation to the disease.

WHAT IS NEW

• Defecation patterns in the three days preceding NEC did not differ from gestational age-matched controls of corresponding postnatal age. Additionally, the first passage of meconium and the duration of meconium passage were comparable between cases and controls. Currently, defecation patterns are not useful as early warning signs for NEC. It remains to be elucidated whether these parameters are different based on the location of intestinal necrosis.

Neonatal pain score after use of paracetamol: Is there a relationship with serum trough concentration at steady state in preterm and term neonates?

OBJECTIVE

An easy to establish and patient-friendly biomarker to guide dosing of paracetamol in neonates is currently not available. The aim of this study was to determine the potential association between the serum trough concentration and area under the curve (AUC) of paracetamol at steady state and differences in pain scores in preterm and term neonates.

MATERIALS AND METHODS

A retrospective observational study was performed, using an academic hospital database to identify neonates treated with intravenous or rectal paracetamol for at least 48 hours. At steady state, serum trough concentrations and the 24-hour AUC were determined. Pain was measured by COMFORTneo scores, before the 1st and 6th dose. Linear regression was performed to assess the association between serum trough concentration and 24-hour AUC and differences in pain scores. Subgroup analyses were performed for patients who received paracetamol due to a COMFORTneo score ≥ 14 (group 1) or who received prophylactic paracetamol because of upcoming surgery (group 2).

RESULTS

21 neonates were included. The median (interquartile range (IQR)) serum trough concentration of paracetamol before the 6th dose was 4.5 mg/L (2.7 - 8.5 mg/L). In subgroup 1, the median (IQR) COMFORTneo scores before the 1st and 6th dose were 17 (16.5 - 20) and 12 (11 - 16.5), respectively. In subgroup 2, the median (IQR) scores were 9 (8 - 10) and 11 (9 - 12), respectively. The serum trough concentration and 24-hour AUC were not associated with reduced pain scores (p = 0.12 and p = 0.67, respectively).

CONCLUSION

No association was found between the serum trough concentration and 24-hour AUC of paracetamol at steady state and differences in pain scores in preterm and term neonates. Future research is needed to prospectively determine a patient-friendly biomarker to optimize the treatment with paracetamol.

Duration of Neonatal Antibiotic Exposure in Preterm Infants in Association with Health and Developmental Outcomes in Early Childhood

Over 90% of preterm neonates are, often empirically, exposed to antibiotics as a potentially life-saving measure against sepsis. Long-term outcome in association with antibiotic exposure (NABE) has insufficiently been studied after preterm birth. We investigated the association of NABE-duration with early-childhood developmental and health outcomes in preterm-born children and additionally assessed the impact of GA on outcomes. Preterm children (GA < 30 weeks) participating in a multicenter cohort study were approached for follow-up. General expert-reviewed health questionnaires on respiratory, atopic and gastrointestinal symptoms were sent to parents of children > 24 months' corrected age (CA). Growth and developmental assessments (Bayley Scales of Infant and Toddler Development (BSID) III) were part of standard care assessment at 24 months' CA. Uni- and multivariate regressions were performed with NABE (per 5 days) and GA (per week) as independent variables. Odds ratios (OR) for health outcomes were adjusted (aOR) for confounders, where appropriate. Of 1079 infants whose parents were approached, 347 (32%) responded at a mean age of 4.6 years (SD 0.9). In children with NABE (97%), NABE duration decreased by 1.6 days (p < 0.001) per week of gestation. Below-average gross-motor development (BSID-III gross-motor score < 8) was associated with duration of NABE (aOR = 1.28; p = 0.04). The aOR for constipation was 0.81 (p = 0.04) per gestational week. Growth was inversely correlated with GA. Respiratory and atopic symptoms were not associated with NABE, nor GA. We observed that prolonged NABE after preterm birth was associated with below-average gross-motor development at 24 months' CA, while a low GA was associated with lower weight and stature Z-scores and higher odds for constipation.

Fecal Volatile Metabolomics Predict Gram-Negative Late-Onset Sepsis in Preterm Infants: A Nationwide Case-Control Study

Early detection of late-onset sepsis (LOS) in preterm infants is crucial since timely treatment initiation is a key prognostic factor. We hypothesized that fecal volatile organic compounds (VOCs), reflecting microbiota composition and function, could serve as a non-invasive biomarker for preclinical pathogen-specific LOS detection. Fecal samples and clinical data of all preterm infants (≤30 weeks’ gestation) admitted at nine neonatal intensive care units in the Netherlands and Belgium were collected daily. Samples from one to three days before LOS onset were analyzed by gas chromatography—ion mobility spectrometry (GC-IMS), a technique based on pattern recognition, and gas chromatography—time of flight—mass spectrometry (GC-TOF-MS), to identify unique metabolites. Fecal VOC profiles and metabolites from infants with LOS were compared with matched controls. Samples from 121 LOS infants and 121 matched controls were analyzed using GC-IMS, and from 34 LOS infants and 34 matched controls using GC-TOF-MS. Differences in fecal VOCs were most profound one and two days preceding Escherichia coli LOS (Area Under Curve; p-value: 0.73; p = 0.02, 0.83; p < 0.002, respectively) and two and three days before gram-negative LOS (0.81; p < 0.001, 0.85; p < 0.001, respectively). GC-TOF-MS identified pathogen-specific discriminative metabolites for LOS. This study underlines the potential for VOCs as a non-invasive preclinical diagnostic LOS biomarker.

Effect of systemic hydrocortisone in ventilated preterm infants on parent-reported behavioural outcomes at 2 years' corrected age: follow-up of a randomised clinical trial

OBJECTIVE

To report the parent-reported behavioural outcomes of infants included in the Systemic Hydrocortisone To Prevent Bronchopulmonary Dysplasia in preterm infants study at 2 years' corrected age (CA).

DESIGN

Randomised placebo-controlled trial.

SETTING

Dutch and Belgian neonatal intensive care units.

PATIENTS

Infants born <30 weeks' gestation and/or birth weight <1250 g, and ventilator dependent in the second week of life.

INTERVENTION

Infants were randomly assigned to a 22-day course of systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190).

MAIN OUTCOME MEASURES

Parent-reported behavioural outcomes at 2 years' CA assessed with the Child Behavior Checklist (CBCL 1½-5).

RESULTS

Parents completed the CBCL of 183 (70% (183/262)) infants (hydrocortisone group, n=96; placebo group, n=87). Multiple imputation was used to account for missing data. Infants with critically elevated T-scores (>55) were found in 22.9%, 19.1% and 29.4% of infants for total, internalising and externalising problems, respectively; these scores were not significantly different between groups (mean difference -1.52 (95% CI -4.00 to 0.96), -2.40 (95% CI -4.99 to 0.20) and -0.81 (95% CI -3.40 to 1.77), respectively). In the subscales, we found a significantly lower T-score for anxiety problems in the hydrocortisone group (mean difference -1.26, 95% CI -2.41 to -0.12).

CONCLUSION

This study found high rates of behaviour problems at 2 years' CA following very preterm birth, but these problems were not associated with hydrocortisone treatment initiated between 7 and 14 days after birth in ventilated preterm infants.

TRIAL REGISTRATION NUMBER

NTR2768; EudraCT 2010-023777-19.

Clinical predictors of bacteraemia in neonates with suspected early-onset sepsis in Malawi: a prospective cohort study

OBJECTIVES

We studied neonates with suspected early-onset sepsis (EOS, sepsis developing in the first 72 hours after delivery) in Malawi to (1) describe clinical characteristics and microbiological findings, (2) identify which patient characteristics may be associated with pathogen positivity on blood culture, and (3) describe mortality and its potential determinants.

DESIGN

Prospective observational study (May 2018-June 2019).

SETTING

Neonatal ward in Queen Elizabeth Central Hospital, the largest government hospital in Malawi.

PATIENTS

All neonates with suspected EOS in whom a blood culture was obtained.

RESULTS

Out of 4308 neonatal admissions, 1244 (28.9%) had suspected EOS. We included 1149 neonates, of which 109 blood cultures had significant growth (9.5%). The most commonly isolated pathogens were Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter cloacae, Escherichia coli and Acinetobacter baumanii. Many of the Gram negatives were extended-spectrum beta lactamase-producing Enterobacteriaceae, and these were 40-100% resistant to first-line and second-line antimicrobials. Gestational age (GA) of <32 weeks was associated with pathogen-positive blood cultures (<28 weeks: adjusted OR (AOR) 2.72, 95% CI 1.04 to 7.13; 28-32 weeks: AOR 2.26, 95% CI 1.21 to 4.21; p=0.005). Mortality was 17.6% (202/1149) and associated with low birth weight (<1000 g: AOR 47.57, 95% CI 12.59 to 179.81; 1000-1500 g: AOR 11.31, 95% CI 6.97 to 18.36; 1500-2500 g: AOR 2.20, 95% CI 1.42 to 3.39; p<0.001), low Apgar scores at 5 min (0-3: AOR 18.60, 95% CI 8.81 to 39.27; 4-6: AOR 4.41, 95% CI 2.81 to 6.93; p<0.001), positive maternal venereal disease research laboratory status (AOR 2.53, 95% CI 1.25 to 5.12; p=0.001) and congenital anomalies (AOR 7.37, 95% CI 3.61 to 15.05; p<0.001). Prolonged rupture of membranes was inversely associated with mortality (AOR 0.43, 95% CI 0.19 to 0.98; p 0.007).

CONCLUSION

In Malawi, EOS was suspected in nearly a third of neonatal admissions and had a high mortality. Ten per cent were culture-confirmed and predicted by low GA. To reduce the impact of suspected neonatal sepsis in least developed countries, improved maternal and antenatal care and development of rapid point of care methods to more accurately guide antimicrobial use could simultaneously improve outcome and reduce antimicrobial resistance.

Getting a grip in the middle of chaos: Preparing for preterm parenthood during a high-risk pregnancy - Parental experiences and needs

Aim

Admitting an infant to a neonatal intensive care unit (NICU) is stressful for parents. A great source of stress is the loss of their desired parental role. This study explores parents’ experiences and needs during a high‐risk pregnancy in preparation for their role as parents of a preterm infant.

Methods

An exploratory qualitative study was conducted among parents with a preterm infant admitted to two level‐III NICUs in the Netherlands. A thematic analysis was performed.

Results

Nineteen interviews were conducted with parents of preterm infants (26–34 weeks gestational age). Getting a grip in the middle of chaos was identified as the central theme. In the pre‐admission phase, coping with potential preterm parenthood was a theme, with coping strategies as subthemes that changed over time from avoidance to being ready to parent a preterm infant. The theme envisioning the NICU emerged in the NICU admission phase, with subthemes preterm care journey and opportunities for involvement fostering parental empowerment.

Conclusion

Timing and content of information about a parental role in the NICU should be tailored to the individual expectant parent. A customisable intervention bundle may provide a vision of the NICU and the parents’ active role in care.

Care pathway for fetal joint contractures, Fetal Akinesia Deformation Sequence and Arthrogryposis Multiplex Congenita

Introduction The majority of arthrogryposis multiplex congenita (AMC) and lethal forms of AMC such as fetal akinesia deformation sequence (FADS) cases are missed prenatally. We have demonstrated the additional value of fetal motor assessment and evaluation in a multidisciplinary team for the period 2007-2016. An applied care pathway for fetuses presenting with joint contracture(s) in one anatomic region (e.g. talipes equinovares), more than one body part with non-progressive contractures and motility (AMC) and with deterioration over time (FADS). Methods The multidisciplinary team of Amsterdam University Medical Centre Expertise Centre FADS and AMC developed the care pathway. Additional tools are provided including a motor assessment by ultrasound examination and postmortem assessment form. Results An eight-step care pathway is presented with a proposed timing for prenatal sonographic examination, genetic examinations, multidisciplinary meetings, prenatal and postnatal counselling of the parents by specialist also treating after birth, follow-up of prenatal and postnatal findings with counselling for future pregnancies. Discussion/conclusion The scheduled serial structural and motor sonograpahic assessment together with follow-up examinations and genetic analysis, should be tailored per prenatal centre per available resources. The multidisciplinary care pathway may pave the way to increase detection rate and diagnosis of isolated contracture(s), talipes equinovares with underlying genetic causes and the rare phenotypes AMC/FADS and prompt treatment after birth within expertise teams.

Cortisol and Cortisone in Early Childhood in Very-Low-Birthweight Infants and Term-Born Infants

INTRODUCTION

Besides programming of the hypothalamic-pituitary-adrenal (HPA) axis, changes in the activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) could contribute to the later metabolic and cardiovascular consequences of preterm birth.

OBJECTIVE

We compared serum cortisol, cortisone, and cortisol/cortisone ratio in early childhood in very-low-birthweight (VLBW) infants and term appropriate for gestational age (AGA) born infants.

METHODS

We included 41 VLBW infants, participating in the randomized controlled Neonatal Insulin Replacement Therapy in Europe trial, and 64 term AGA-born infants. Cortisol and cortisone were measured in blood samples taken at 6 months and 2 years corrected age (VLBW children) and at 3 months and 1 and 2 years (term children). At 2 years of (corrected) age (HDL) cholesterol, triglycerides, glucose, and insulin were also measured.

RESULTS

During the first 2 years of life, cortisol/cortisone ratio is higher in VLBW children compared to term children. In the total group of children, cortisol/cortisone ratio is positively related to triglycerides at 2 years of (corrected) age. In VLBW children, over the first 2 years of life both cortisol and cortisone are higher in the early-insulin group compared to the standard care group.

CONCLUSIONS

In VLBW infants, lower 11β-HSD2 activity probably contributes to the long-term metabolic and cardiovascular risks. In VLBW infants, early insulin treatment could affect programming of the HPA axis, resulting in higher cortisol and cortisone levels during early childhood.

Profound Pathogen-Specific Alterations in Intestinal Microbiota Composition Precede Late-Onset Sepsis in Preterm Infants: A Longitudinal, Multicenter, Case-Control Study

BACKGROUND

The role of intestinal microbiota in the pathogenesis of late-onset sepsis (LOS) in preterm infants is largely unexplored but could provide opportunities for microbiota-targeted preventive and therapeutic strategies. We hypothesized that microbiota composition changes before the onset of sepsis, with causative bacteria that are isolated later in blood culture.

METHODS

This multicenter case-control study included preterm infants born under 30 weeks of gestation. Fecal samples collected from the 5 days preceding LOS diagnosis were analyzed using a molecular microbiota detection technique. LOS cases were subdivided into 3 groups: gram-negative, gram-positive, and coagulase-negative Staphylococci (CoNS).

RESULTS

Forty LOS cases and 40 matched controls were included. In gram-negative LOS, the causative pathogen could be identified in at least 1 of the fecal samples collected 3 days prior to LOS onset in all cases, whereas in all matched controls, this pathogen was absent (P = .015). The abundance of these pathogens increased from 3 days before clinical onset. In gram-negative and gram-positive LOS (except CoNS) combined, the causative pathogen could be identified in at least 1 fecal sample collected 3 days prior to LOS onset in 92% of the fecal samples, whereas these pathogens were present in 33% of the control samples (P = .004). Overall, LOS (expect CoNS) could be predicted 1 day prior to clinical onset with an area under the curve of 0.78.

CONCLUSIONS

Profound preclinical microbial alterations underline that gut microbiota is involved in the pathogenesis of LOS and has the potential as an early noninvasive biomarker.

IGF-I, Growth, and Body Composition in Preterm Infants up to Term Equivalent Age

Context

There are concerns that a higher fat mass in the early life of preterm infants is associated with adverse cardiometabolic outcomes in young adulthood.

Objective

To investigate the role of IGF-I and growth in determining body composition of preterm infants at term equivalent age.

Methods

An observational study was conducted from August 2015 to August 2018. From birth to term equivalent age, IGF-I levels were measured bi-weekly and growth was assessed weekly. At term equivalent age, body composition was assessed through air displacement plethysmography; 65 infants with a gestational age of 24 to 32 weeks were assessed at term equivalent age, of whom 58 completed body composition measurement. The main outcome measures were fat (free) mass (g) and fat (free) mass percentage at term equivalent age.

Results

In the first month of life, each 0.1 nmol/L per week increase in IGF-I was associated with a 465 g (SE 125 g) increase in fat free mass. A greater increase in weight SDS in the first month of life was associated with a higher fat free mass percentage (B 200.9; 95% CI, 12.1-389.6). A higher head circumference SDS was associated with more fat free mass (r = 0.46; 95% CI, 0.21-0.65). However, a greater increase in weight SDS up to term equivalent age was associated with a lower fat free mass percentage (B -55.7, SE 9.4).

Conclusion

These findings suggest that impaired growth in the first month of life is associated with a less favorable body composition at term equivalent age.

Early Nutrition during Hospitalization in Relation to Bone Health in Preterm Infants at Term Age and Six Months Corrected Age

Aim: to evaluate the potential association of macronutrient intake in the first postnatal weeks on bone mineral content (BMC) and bone mineral density (BMD) in extremely and very preterm infants. Methods: fifty-eight extremely and very preterm infants were included. Daily macronutrient intake was calculated in g kg⁻¹ day⁻¹ from birth up to 36 weeks postmenstrual age. A dual-energy X-ray absorptiometry whole body scan was used to assess BMC and BMD in preterm infants at term corrected age (TCA) and six months corrected age (CA). Results: fat intake (g kg⁻¹ day⁻¹) in the first four postnatal weeks was positively associated with BMC and BMD at TCA. At six months CA, protein and fat intake (g kg⁻¹ day⁻¹) in the first weeks of life were both individual predictors for BMD. Fat intake (g kg⁻¹ day⁻¹) in the first four postnatal weeks was significantly associated with BMC at six months CA. Conclusion: the association of macronutrient intake in the first postnatal weeks on BMC or BMD, at TCA and six months CA, suggest that early nutritional intervention immediately after birth and during early infancy is important for bone health in the first months of life.

Real-time continuous glucose monitoring in preterm infants (REACT): an international, open-label, randomised controlled trial

BACKGROUND

Hyperglycaemia and hypoglycaemia are common in preterm infants and have been associated with increased risk of mortality and morbidity. Interventions to reduce risk associated with these exposures are particularly challenging due to the infrequent measurement of blood glucose concentrations, with the potential of causing more harm instead of improving outcomes for these infants. Continuous glucose monitoring (CGM) is widely used in adults and children with diabetes to improve glucose control, but has not been approved for use in neonates. The REACT trial aimed to evaluate the efficacy and safety of CGM in preterm infants requiring intensive care.

METHODS

This international, open-label, randomised controlled trial was done in 13 neonatal intensive care units in the UK, Spain, and the Netherlands. Infants were included if they were within 24 h of birth, had a birthweight of 1200 g or less, had a gestational age up to 33 weeks plus 6 days, and had parental written informed consent. Infants were randomly assigned (1:1) to real-time CGM or standard care (with masked CGM for comparison) using a central web randomisation system, stratified by recruiting centre and gestational age (<26 or ≥26 weeks). The primary efficacy outcome was the proportion of time sensor glucose concentration was 2·6-10 mmol/L for the first week of life. Safety outcomes related to hypoglycaemia (glucose concentrations <2·6 mmol/L) in the first 7 days of life. All outcomes were assessed on the basis of intention to treat in the full analysis set with available data. The study is registered with the International Standard Randomised Control Trials Registry, ISRCTN12793535.

FINDINGS

Between July 4, 2016, and Jan 27, 2019, 182 infants were enrolled, 180 of whom were randomly assigned (85 to real-time CGM, 95 to standard care). 70 infants in the real-time CGM intervention group and 85 in the standard care group had CGM data and were included in the primary analysis. Compared with infants in the standard care group, infants managed using CGM had more time in the 2·6-10 mmol/L glucose concentration target range (mean proportion of time 84% [SD 22] vs 94% [11]; adjusted mean difference 8·9% [95% CI 3·4-14·4]), equivalent to 13 h (95% CI 5-21). More infants in the standard care group were exposed to at least one episode of sensor glucose concentration of less than 2·6 mmol/L for more than 1 h than those in the intervention group (13 [15%] of 85 vs four [6%] of 70). There were no serious adverse events related to the use of the device or episodes of infection.

INTERPRETATION

Real-time CGM can reduce exposure to prolonged or severe hyperglycaemia and hypoglycaemia. Further studies using CGM are required to determine optimal glucose targets, strategies to obtain them, and the potential effect on long-term health outcomes.

FUNDING

National Institute for Health Research Efficacy and Mechanisms Evaluation Programme.

Predictive factors for surgical treatment in preterm neonates with necrotizing enterocolitis: a multicenter case-control study

Necrotizing enterocolitis (NEC) is one of the most common and lethal gastrointestinal diseases in preterm infants. Early recognition of infants in need for surgical intervention might enable early intervention. In this multicenter case-control study, performed in nine neonatal intensive care units, preterm born infants (< 30 weeks of gestation) diagnosed with NEC (stage ≥ IIA) between October 2014 and August 2017 were divided into two groups: (1) medical (conservative treatment) and (2) surgical NEC (sNEC). Perinatal, clinical, and laboratory parameters were collected daily up to clinical onset of NEC. Univariate and multivariate logistic regression analyses were applied to identify potential predictors for sNEC. In total, 73 preterm infants with NEC (41 surgical and 32 medical NEC) were included. A low gestational age (p value, adjusted odds ratio [95%CI]; 0.001, 0.91 [0.86-0.96]), no maternal corticosteroid administration (0.025, 0.19 [0.04-0.82]), early onset of NEC (0.003, 0.85 [0.77-0.95]), low serum bicarbonate (0.009, 0.85 [0.76-0.96]), and a hemodynamically significant patent ductus arteriosus for which ibuprofen was administered (0.003, 7.60 [2.03-28.47]) were identified as independent risk factors for sNEC.Conclusions: Our findings may support the clinician to identify infants with increased risk for sNEC, which may facilitate early decisive management and consequently could result in improved prognosis. What is Known: • In 27-52% of the infants with NEC, a surgical intervention is indicated during its disease course. • Absolute indication for surgical intervention is bowel perforation, whereas fixed bowel loop or clinical deterioration highly suggestive of bowel perforation or necrosi, is a relative indication. What is New: • Lower gestational age, early clinical onset, and no maternal corticosteroids administration are predictors for surgical NEC. • Low serum bicarbonate in the 3 days prior clinical onset and patent ductus arteriosus for which ibuprofen was administered predict surgical NEC.

Propofol for endotracheal intubation in neonates: a dose-finding trial

OBJECTIVE

To find propofol doses providing effective sedation without side effects in neonates of different gestational ages (GA) and postnatal ages (PNA).

DESIGN AND SETTING

Prospective multicentere dose-finding study in 3 neonatal intensive care units.

PATIENTS

Neonates with a PNA <28 days requiring non-emergency endotracheal intubation.

INTERVENTIONS

Neonates were stratified into 8 groups based on GA and PNA. The first 5 neonates in every group received a dose of 1.0 mg/kg propofol. Based on sedative effect and side effects, the dose was increased or decreased in the next 5 patients until the optimal dose was found.

MAIN OUTCOME MEASURES

The primary outcome was the optimal single propofol starting dose that provides effective sedation without side effects in each age group.

RESULTS

After inclusion of 91 patients, the study was prematurely terminated because the primary outcome was only reached in 13% of patients. Dose-finding was completed in 2 groups, but no optimal propofol dose was found. Effective sedation without side effects was achieved more often after a starting dose of 2.0 mg/kg (28%) than after 1.0 mg/kg (3%) and 1.5 mg/kg (9%). Propofol-induced hypotension occurred in 59% of patients. Logistic regression analyses showed that GA and PNA did not predict effective sedation or the occurrence of hypotension.

CONCLUSIONS

Effective sedation without side effects is difficult to achieve with propofol and the optimal dose in different age groups of neonates could not be determined. The sedative effect of propofol and the occurrence of hypotension are unpredictable and show large inter-individual variability in the neonatal population.

The prognostic value of NIRS in preterm infants with (suspected) late-onset sepsis in relation to long term outcome: A pilot study

Late-onset sepsis is frequently seen in preterm infants and is associated with poor neurodevelopmental outcome. White matter damage is proposed as substrate of poor outcome, with contributing factors as regional hypoxia and effects of cytokines on oligodendrocytes. We investigated the relation between cerebral oxygenation during (suspected) late-onset sepsis and neurodevelopmental outcome. Prospective cohort study, including preterm infants (gestational age <32 weeks and/or birthweight <1500 grams) with (suspected) late-onset sepsis underwent NIRS registration during the first 72 hours of suspected late-onset sepsis. At two years corrected age neurodevelopment was scored using the Bayley Scales of Infant Development-II. Thirty-two infants were included. Twenty-seven infants were identified with proven late-onset sepsis and five infants had clinical sepsis without positive blood culture. In this study, late-onset sepsis was predominantly caused by coagulase negative staphylococci (CoNS) (72%). All NIRS values were within normal limits. No association was found between NIRS and impaired neurodevelopmental outcome (n = 4) at corrected age two years: composite cognitive score 105 (80-115), composite motor score 103 (82-118) (median and range). In this pilot study, late-onset sepsis (predominantly caused by CoNS with a relatively mild clinical course), was not associated with aberrant NIRS values, nor with impaired neurodevelopmental outcome. Further research might establish our findings and elucidate effects of other micro-organisms on cerebral perfusion.

Blood pressure of 12-year-old children born after foetal growth restriction due to hypertensive disorders of pregnancy; relation to neonatal, life style, and family characteristics

INTRODUCTION

Children born from pregnancies that were complicated by hypertensive disorders of pregnancy (HDP, i.e. pre-eclampsia or HELLP syndrome) are at risk for elevated systolic and diastolic blood pressure (SBP/DBP) in childhood.

AIM

To examine which neonatal, life style, and family characteristics are associated with SBP/DBP.

METHODS

Study design: Prospective cohort.

SUBJECTS

12-years-old preterm and growth restricted children born to women with severe early-onset HDP.

OUTCOME MEASURES

SBP/DBP standard deviation scores (SDS), corrected for age, gender and height.

RESULTS

Ninety-two of the 174 mother-child pairs participated at age 12 years (mean gestational age 32 weeks, range 27 to 38 weeks, mean birth weight ratio (BWR) 0.68, range 0.33 to 0.99). Mean SBP SDS was 0.70 ± 0.81 and mean DBP SDS was 0.14 ± 0.78. SBP SDS was positively associated with very preterm birth (beta 0.53, p = .002), with child BMI SDS (beta 0.25, p = .035), and maternal BMI ≥ 25 kg/m² at 12 years (beta 0.49, p = .003), and not with pre-pregnancy maternal BMI ≥ 25 kg/m². DBP SDS was positively associated with maternal BMI ≥ 25 kg/m² (beta 0.35, p 0.002). BWR was not associated with blood pressure.

CONCLUSIONS

In 12-years old children born to women with HDP, higher systolic blood pressure values were associated with very preterm birth and child BMI. Higher blood pressure values were also associated with current maternal BMI ≥ 25 kg/m². Life style adaptations may benefit long-term cardio vascular health in mother and child.

Fetal akinesia deformation sequence, arthrogryposis multiplex congenita, and bilateral clubfeet: Is motor assessment of additional value for in utero diagnosis? A 10-year cohort study

Objective

The diagnosis of fetal akinesia deformation sequence (FADS) is a challenge. Motor assessment is of additional value to advanced ultrasound examinations (AUE) for in utero FADS diagnosis before 24 weeks of gestation.

Methods

All consecutive fetuses with greater than or equal to two contractures on the 20 week structural anomaly scan (2007–2016) were included. Findings at AUE, including motor assessment were analysed and related to outcome.

Results

Sixty‐six fetuses fulfilled the inclusion criteria. On the basis of the first AUE, FADS was suspected in 13 of 66, arthrogryposis multiplex congenita (AMC) in 12 of 66, bilateral pes equinovares (BPEV) in 40 of 66, and Holt‐Oram syndrome in one of 66. On the basis of the first motor assessment, the suspected diagnosis changed in 19 of 66, in 13 of 66 worsening to FADS, six of 66 amelioration from FADS, and confirmed FADS in seven of 13. The result was 20 FADS, seven AMC, and 38 BPEV. Second AUE in 44 fetuses showed additional contractures in two of eight FADS, and one intrauterine fetal death (IUFD). The second motor assessment changed the diagnosis in three of 43, one worsening from BPEV into FADS, two ameliorations from FADS, and confirmed FADS in seven by deterioration of motility. The result was nine FADS, six AMC, and 29 BPEV.

Conclusion

The results suggest that motor assessment has additional value to distinguish between FADS, AMC, and BPEV.

Systematic motor assessment for differentiation, quality, and quantity of the movements has been performed in a high risk population for FADS.¹

This analysis revealed abnormal quality in all fetuses with deterioration in a 2‐week period, reduced differentiation in the majority and only half showed abnormal quantity.

This study evaluates whether motor assessment in addition to advanced ultrasound examination in case of multiple contractures, supports the timely diagnosis of FADS.

Medication Use During Pregnancy and Lactation in a Dutch Population

BACKGROUND:

Medication use during pregnancy and lactation can be unavoidable, but knowledge on safety for the fetus or breastfed infant is limited among patients and healthcare providers.

RESEARCH AIM:

This study aimed to determine (a) the prevalence of medication use in pregnant and lactating women in a tertiary academic center, (b) the types and safety of these medicines, and (c) the influence of medication use on initiation of breastfeeding.

METHODS:

This study used a cross-sectional survey among women ( N = 292) who underwent high-risk or low-risk deliveries. Data about their use of prescribed, over-the-counter, and homeopathic medication during pregnancy were obtained through a structured interview, followed by a questionnaire during lactation. Safety was classified according to the risk classification system from the Dutch Teratological Information Service.

RESULTS:

Overall, 95.5% of participants used medication. One third of participants used at least one medicine with an unknown risk for the fetus. Teratogenic medication was used by 6.5% of participants, whereas 29.5% used medication with a (suspected) pharmacological effect on the fetus. Lactation was initiated by 258 (88.7%) participants, of which 84.2% used medication while breastfeeding. In 3.8% of participants, this medication was classified unsafe, but none used medication with an unknown risk. One-third of the nonlactating participants decided not to initiate breastfeeding because of medication use. In 70% of participants, this decision was appropriate.

CONCLUSION:

The prevalence of overall use of medication in Dutch pregnant and lactating women admitted to a tertiary center was high. There is an urgent need for pharmacometric studies for determination of the safe use of the most frequently used medicines during pregnancy or lactation.

Risk Factors for Late-Onset Sepsis in Preterm Infants: A Multicenter Case-Control Study

BACKGROUND

Late-onset sepsis (LOS) in preterm infants is a leading cause of mortality and morbidity. Timely recognition and initiation of antibiotics are important factors for improved outcomes. Identification of risk factors could allow selection of infants at an increased risk for LOS.

OBJECTIVES

The aim was to identify risk factors for LOS.

METHODS

In this multicenter case-control study, preterm infants born at ≤30 weeks of gestation were included at 9 neonatal intensive care units. Detailed demographical and clinical data were collected daily up to day 28 postnatally. Clinical and demographic risk factors were identified using univariate and multivariate regression analyses in a 1: 1 matched case-control cohort.

RESULTS

In total, 755 infants were included, including 194 LOS cases (41 gram-negative cases, 152 gram-positive cases, and 1 fungus). In the case-control cohort, every additional day of parenteral feeding increased the risk for LOS (adjusted OR = 1.29; 95% CI 1.07-1.55; p = 0.006), whereas antibiotics administration decreased this risk (OR = 0.08; 95% CI 0.01-0.88; p = 0.039). These findings could largely be attributed to specific LOS-causative pathogens, since these predictive factors could be identified for gram-positive, but not for gram-negative, LOS cases. Specifically cephalosporins administration prior to clinical onset was inversely related to coagulase-negative staphylococcus LOS (CoNS-LOS) development. Formula feeding was an independent risk factor for development of CoNS-LOS (OR = 3.779; 95% CI 1.257-11.363; p = 0.018).

CONCLUSION

The length of parenteral feeding was associated with LOS, whereas breastmilk administration was protective against CoNS-LOS. A rapid advancement of enteral feeding, preferably with breastmilk, may proportionally reduce the number of parenteral feeding days and consequently the risk for LOS.

Protocol of a randomised controlled trial of real-time continuous glucose monitoring in neonatal intensive care 'REACT'

INTRODUCTION

Hyperglycaemia is common in the very preterm infant and has been associated with adverse outcomes. Preventing hyperglycaemia without increasing the risk of hypoglycaemia has proved challenging. The development of real-time continuous glucose monitors (CGM) to inform treatment decisions provides an opportunity to reduce this risk. This study aims to assess the feasibility of CGM combined with a specifically designed paper guideline to target glucose control in the preterm infant.

METHODS AND ANALYSES

The Real Time Continuous Glucose Monitoring in Neonatal Intensive Care (REACT) trial is an international multicentre randomised controlled trial. 200 preterm infants ≤1200 g and ≤24 hours of age will be randomly allocated to either real-time CGM or standard care (with blinded CGM data collection). The primary outcome is time in target 2.6-10 mmol/L during the study intervention assessed using CGM. Secondary outcomes include efficacy relating to glucose control, utility including staff acceptability, safety outcomes relating to incidence and prevalence of hypoglycaemia and health economic analyses.

ETHICS AND DISSEMINATION

The REACT trial has been approved by the National Health Service Health Research Authority National Research Ethics Service Committee East of England (Cambridge Central); Medical Ethics Review Committee, VU University Medical Centre, Amsterdam, The Netherlands and the Research Ethics Committee, Sant Joan de Déu Research Foundation, Barcelona, Spain. Recruitment began in July 2016 and will continue until mid-2018. The trial has been adopted by the National Institute of Health Research Clinical Research Network portfolio (ID: 18826) and is registered with anInternational Standard Randomised Control Number (ISRCTN registry ID: 12793535). Dissemination plans include presentations at scientific conferences, scientific publications and efforts at stakeholder engagement.

TRIAL REGISTRATION NUMBER

ISRCTN12793535; Pre-results.

Evaluation of a real-time PCR assay for detection and quantification of bacterial DNA directly in blood of preterm neonates with suspected late-onset sepsis

Background

Rapid and accurate diagnosis of neonatal sepsis is highly warranted because of high associated morbidity and mortality. The aim of this study was to evaluate the performance of a novel multiplex PCR assay for diagnosis of late-onset sepsis and to investigate the value of bacterial DNA load (BDL) determination as a measure of infection severity.

Methods

This cross-sectional study was conducted in a neonatal intensive care unit. Preterm and/or very low birth weight infants suspected for late-onset sepsis were included. Upon suspicion of sepsis, a whole blood sample was drawn for multiplex PCR to detect the eight most common bacteria causing neonatal sepsis, as well as for blood culture. BDL was determined in episodes with a positive multiplex PCR.

Results

In total, 91 episodes of suspected sepsis were investigated, and PCR was positive in 53 (58%) and blood culture in 60 (66%) episodes, yielding no significant difference in detection rate (p = 0.17). Multiplex PCR showed a sensitivity of 77%, specificity of 81%, positive predictive value of 87%, and negative predictive value of 68% compared with blood culture. Episodes with discordant results of PCR and blood culture included mainly detection of coagulase-negative staphylococci (CoNS). C-reactive protein (CRP) level and immature to total neutrophil (I/T) ratio were lower in these episodes, indicating less severe disease or even contamination. Median BDL was high (4.1 log₁₀ cfu Eq/ml) with a wide range, and was it higher in episodes with a positive blood culture than in those with a negative blood culture (4.5 versus 2.5 log₁₀ cfu Eq/ml; p < 0.0001). For CoNS infection episodes BDL and CRP were positively associated (p = 0.004), and for Staphylococcus aureus infection episodes there was a positive association between BDL and I/T ratio (p = 0.049).

Conclusions

Multiplex PCR provides a powerful assay to enhance rapid identification of the causative pathogen in late-onset sepsis. BDL measurement may be a useful indicator of severity of infection.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2010-4) contains supplementary material, which is available to authorized users.

NEOnatal Central-venous Line Observational study on Thrombosis (NEOCLOT): evaluation of a national guideline on management of neonatal catheter-related thrombosis

BACKGROUND

In critically ill (preterm) neonates, central venous catheters (CVCs) are increasingly used for administration of medication or parenteral nutrition. A serious complication, however, is the development of catheter-related thrombosis (CVC-thrombosis), which may resolve by itself or cause severe complications. Due to lack of evidence, management of neonatal CVC-thrombosis varies among neonatal intensive care units (NICUs). In the Netherlands an expert-based national management guideline has been developed which is implemented in all 10 NICUs in 2014.

METHODS

The NEOCLOT study is a multicentre prospective observational cohort study, including 150 preterm and term infants (0-6 months) admitted to one of the 10 NICUs, developing CVC-thrombosis. Patient characteristics, thrombosis characteristics, risk factors, treatment strategies and outcome measures will be collected in a web-based database. Management of CVC-thrombosis will be performed as recommended in the protocol. Violations of the protocol will be noted. Primary outcome measures are a composite efficacy outcome consisting of death due to CVC-thrombosis and recurrent thrombosis, and a safety outcome consisting of the incidence of major bleedings during therapy. Secondary outcomes include individual components of primary efficacy outcome, clinically relevant non-major and minor bleedings and the frequency of risk factors, protocol variations, residual thrombosis and post thrombotic syndrome.

DISCUSSION

The NEOCLOT study will evaluate the efficacy and safety of the new, national, neonatal CVC-thrombosis guideline. Furthermore, risk factors as well as long-term consequences of CVC-thrombosis will be analysed.

TRIAL REGISTRATION

Trial registration: Nederlands Trial Register NTR4336 . Registered 24 December 2013.

Development of severe bronchopulmonary dysplasia is associated with alterations in fecal volatile organic compounds

BackgroundThe aim of this study was to evaluate the potential of fecal volatile organic compounds (VOCs), obtained by means of an electronic nose device (Cyranose 320), as early non-invasive biomarker for BPD.MethodsIn this nested case-control study performed at three Neonatal Intensive Care Units, fecal samples obtained at postnatal age of 7, 14, 21, and 28 days from preterm infants with severe bronchopulmonary dysplasia (BPD) were compared with fecal VOC profiles from matched controls. Microbiota analysis was performed by means of IS-pro technique on fecal samples collected at 28 days postnatally.ResultsVOC profiles of infants developing severe BPD (n=15) could be discriminated from matched controls (n=15) at postnatal age of 14 days (area under the curve (±95% confidence interval), P-value, sensitivity, specificity; 0.72 (0.54-0.90), 0.040, 60.0%, 73.3%), 21 days (0.71 (0.52-0.90), 0.049, 66.7%, 73.3%) and 28 days (0.77 (0.59-0.96), 0.017, 69.2%, 69.2%) but not at 7 days. Intestinal microbiota did not differ between BPD subjects and controls.ConclusionFecal VOC profiles of infants developing BPD could be differentiated from controls at postnatal day 14, 21, and 28. VOC differences could not be directed to intestinal microbiota alterations but presumably reflect local and systemic metabolic and inflammatory pathways associated with BPD.

Risk Factors for Necrotizing Enterocolitis: A Prospective Multicenter Case-Control Study

BACKGROUND

The identification of independent clinical risk factors for necrotizing enterocolitis (NEC) may contribute to early selection of infants at risk, allowing for the development of targeted strategies aimed at the prevention of NEC.

OBJECTIVE

The objective of this study was to identify independent risk factors contributing to the development of NEC in a large multicenter cohort.

METHODS

This prospective cohort study was performed in 9 neonatal intensive care units. Infants born at a gestational age ≤30 weeks were included. Demographic and clinical data were collected daily until day 28 postnatally. Factors predictive of the development of NEC were identified using univariate and multivariable analyses in a 1: 5 matched case-control cohort.

RESULTS

In total, 843 infants (56 NEC cases) were included in this study. In the case-control cohort, univariate analysis identified sepsis prior to the onset of NEC and formula feeding to be associated with an increased risk of developing NEC, whereas the administration of antibiotics directly postpartum was inversely associated with NEC. In a multivariable logistic regression model, enteral feeding type and the number of days parenterally fed remained statistically significantly associated with NEC, whereas the administration of antibiotics directly after birth was associated with a lower risk of developing NEC.

CONCLUSIONS

Formula feeding and prolonged (duration of) parenteral feeding were associated with an increased risk of NEC. Contrary to expectations, the initiation of treatment with antibiotics within 24 h after birth was inversely associated with NEC.

Growth throughout childhood of children born growth restricted

OBJECTIVE

Many studies that examine growth in growth-restricted children at birth do not discriminate between fetal growth restriction (FGR) and small for gestational age (SGA). These terms however are not synonymous. In SGA, stunting and increased weight gain have been reported. We do not know if this holds true for FGR. Our aim was to study postnatal growth until age 12.5 years in a cohort of children born FGR due to early onset placental insufficiency, and its relation to FGR severity.

DESIGN

Prospective cohort study, follow-up of an antenatal randomised controlled trial in two tertiary centres.

PATIENTS

Children aged 12.5 years born after FGR, with mothers who had severe early onset hypertensive pregnancy disorders (N=96).

MAIN OUTCOME MEASURES

Anthropometry at age 12.5 years in SD scores (SDS).

RESULTS

Mean height SDS (SD) corrected for target height was -0.09 (0.94), mean body mass index (BMI) SDS was 0.00 (1.16) and mean head circumference SDS was -0.37 (1.11). Catch-up growth was at fastest rate between term age and 3 months and similar for height (0.55 SDS/months) and weight (0.49 SDS/months). Neither FGR severity nor gestational age was related to height and BMI at age 12.5 years.

CONCLUSIONS

Children born growth restricted due to early onset placental insufficiency have height and BMI scores comparable to their age-matched peers at age 12.5 years. FGR severity was not related to height and BMI at age 12.5 years. These reassuring results differ from most studies that examine SGA children.

IGF-I and relation to growth in infancy and early childhood in very-low-birth-weight infants and term born infants

Background

In very-low-birth-weight infants IGF-I plays an important role in postnatal growth restriction and is probably also involved in growth restriction in childhood. We compared IGF-I and its relation to growth in early childhood in very-low-birth-weight infants and term appropriate for gestational age born infants.

Methods

We included 41 very-low-birth-weight and 64 term infants. Anthropometry was performed at all visits to the outpatient clinic. IGF-I and insulin were measured in blood samples taken at 6 months and 2 years corrected age (very-low-birth-weight children) and at 3 months, 1 and 2 years (term children).

Results

Over the first 2 years of life growth parameters are lower in very-low-birth-weight children compared to term children, but the difference in length decreases significantly. During the first 2 years of life IGF-I is higher in very-low-birth-weight children compared to term children. In both groups there is a significant relationship between IGF-I and (change in) length and weight over the first 2 years of life and between insulin and change in total body fat.

Conclusions

Considering the relation of IGF-I to growth and the decrease in difference in length, higher IGF-I levels in very-low-birth-weight infants in early childhood probably have an important role in catch-up growth in length.

Outcome of isolated gastroschisis; an international study, systematic review and meta-analysis

OBJECTIVE

To determine outcome of children born with isolated gastroschisis (no extra-gastrointestinal congenital abnormalities).

STUDY DESIGN

International cohort study and meta-analysis.

PRIMARY OUTCOME

time to full enteral feeding (TFEF); secondary outcomes: Duration of mechanical ventilation, length of stay (LOS), mortality and differences in outcome between simple and complex gastroschisis (complex; born with bowel atresia, volvulus, perforation or necrosis). To compare the cohort study results with literature three databases were searched. Studies were eligible for inclusion if cases were born in developed countries with isolated gastroschisis after 1990, number of cases >20 and TFEF was reported.

RESULTS

The cohort study included 204 liveborn cases of isolated gastroschisis. The TFEF, median duration of ventilation and LOS was, 26days (range 6-515), 2days (range 0-90) and 33days (range 11-515), respectively. Overall mortality was 10.8%. TFEF and LOS were significantly longer (P<0.0001) and mortality was fourfold higher in the complex group. Seventeen studies, amongst the current study, were included for further meta-analysis comprising a total of 1652 patients. Mean TFEF was 35.3±4.4days, length of ventilation was 5.5±2.0days, LOS was 46.4±5.2days and mortality risk was 0.06 [0.04-0.07 95%CI]. Outcome of simple and complex gastroschisis was described in five studies. TFEF, ventilation time, LOS were significant longer and mortality rate was 3.64 [1.95-6.83 95%CI] times higher in complex cases.

CONCLUSIONS

These results give a good indication of the expected TFEF, ventilation time and LOS and mortality risk in children born with isolated gastroschisis, although ranges remain wide. This study shows the importance of dividing gastroschisis into simple and complex for the prediction of outcome.

Severe Neonatal Anaemia, MRI Findings and Neurodevelopmental Outcome

BACKGROUND AND OBJECTIVE

Severe neonatal anaemia can impair cerebral oxygen supply. Data on long-term outcomes following severe neonatal anaemia are scarce.

METHODS

Clinical data and neurodevelopmental outcome of 49 (near) term infants with haemoglobin concentration after birth <6.0 mmol/l were retrospectively collected and analysed. In a subgroup of 28 patients, amplitude-integrated EEG was available and in 25 infants cerebral MRI was obtained. Infants were followed up at 14-35 months of age and assessed with the Griffiths Scale of Mental Development or Bayley Scale of Infant Development.

RESULTS

Eighteen patients (37%) died during the neonatal period. In 25 patients MRI was performed. A predominant pattern of injury on MRI was seen in the basal ganglia and thalami in 7 patients (28%), whereas some form of white matter injury was present in 16 (64%) and a combination in 3 (12%). Follow-up data were available for 26 patients (84% of survivors). Formal assessment of neurodevelopmental outcome was performed in 20 of 31 (65%) infants who survived (median age: 19 months, range: 14-35). Sixteen infants (80%) had a developmental quotient appropriate for age in the first 2 years after birth. On motor outcome, 1 patient (5%) scored below average (Z-score -1.10). One patient developed cerebral palsy.

CONCLUSION

Early neurodevelopmental outcome in surviving patients with severe neonatal anaemia was within the normal range in the majority of the survivors. MRI showed mild-to-moderate white matter injury in two thirds of the infants. Prospectively collected data with a longer follow-up period are needed.

Early-Onset Severe Encephalopathy with Epilepsy: The BRAT1 Gene Should Be Added to the List of Causes

A variety of pathologies can underlie early-onset severe encephalopathy with epilepsy. To aid the diagnostic process in such patients we present an overview of causes, including the rapidly expanding list of genes involved. When no explanation is found, whole-exome sequencing (WES) can be used in an attempt to identify gene defects in patients suspected to suffer from a genetic form. We describe three siblings, born to consanguineous parents, with a lethal severe epileptic encephalopathy with early-infantile onset, including their magnetic resonance imaging, electroencephalography and, in one case, neuropathological findings. Using WES a homozygous frameshift mutation in the BRAT1 gene, c.638dup p.(Val214Glyfs*189), was identified. We present our cases in the context of all published cases with mutations in the BRAT1 gene and conclude that BRAT1 should be added to the growing list of genes related to early-onset severe encephalopathy with epilepsy.

Effect of (minor or major) maternal trauma on fetal motility: A prospective study

BACKGROUND

Fetal motility represents the spontaneous activity of the central nervous system and as such can be used to evaluate its functional integrity. Maternal mechanical trauma in pregnancy is a risk factor for hypoxic ischemic brain injury and can potentially affect the CNS and fetal motility.

AIM

To study motility in fetuses after maternal trauma.

STUDY DESIGN

Prospective study; 1-h sonographic observations at 2-8h (T1), 24-72h (T2) and >72h (T3) after trauma.

SUBJECTS

Fetuses exposed to trauma after 20weeks gestational age.

OUTCOME MEASURES

Motor aspects; differentiation into specific movement patterns, quality and quantity of general movements were compared to a normal population. Obstetrical outcome; neurological outcome at term and 1year of age.

RESULTS

Sixteen fetuses were examined between 2012 and 2014. Median gestational age at time of trauma was 25+6 (range 20-38) weeks. Most traumas were traffic accidents or falls, injuries were mainly minor. Motility assessment showed abnormal differentiation in 2/16; 2/14 and 0/16; abnormal quality in 2/16; 3/14 and 6/16; and abnormal quantity in 6/16, 9/14 and 9/16 at T1, T2 and T3 respectively. Preterm delivery occurred once. Neurological development was normal in 13/14 infants at term and 14/14 at one year.

CONCLUSIONS

This study shows that maternal trauma affected fetal motility in the majority of the fetuses. The changes in motility support the concern that even minor mechanical trauma may have influence on the functional integrity of the central nervous system, although no neurological sequelae were present at 1year.

Long-term motor and behavioral outcome after perinatal hypoxic-ischemic encephalopathy

BACKGROUND

A cohort of children born with perinatal hypoxic-ischemic encephalopathy (HIE) was followed prospectively until school age.

AIMS

To describe motor outcome and behavioral functioning of school-age children after perinatal HIE and the relationship with neonatal MRI and outcome at age 2.

METHODS

Twenty-five children (19 males), born at term with perinatal HIE, were assessed at a mean age of 7 y 6 m (range 6 y 4 m-8 y 2 m). Motor ability was assessed with the Movement Assessment Battery for Children (2nd version) and behavioral functioning was assessed with the Child Behavior Checklist. Neonatal MRI was scored according to Barkovich classification.

RESULTS

Of the 25 included children, eight had cerebral palsy (CP). Of the 17 children without CP, nine had impaired motor ability (of which 3 scored definitely abnormal), and four had behavioral problems. There was a significant difference in motor performance (p = 0.008) between children with normal and children with abnormal neonatal MRI. Two (of four) children with normal motor ability and seven (of 14) children with normal neurological examination at age 2 showed impaired motor ability at school age.

CONCLUSIONS

Half of the children without CP had impaired motor ability at school age. A normal outcome after HIE at young age does not necessarily imply a good outcome at school age, even when neonatal MRI does not show any abnormalities. More research is needed on the behavioral and cognitive consequences of HIE at school age and on the consequences for quality of life for children with and without CP.

Components of the metabolic syndrome in early childhood in very-low-birth-weight infants

BACKGROUND/AIMS

Term small-for-gestational-age and preterm born infants have an increased prevalence of metabolic syndrome components already in childhood. Data in very-low-birth-weight (VLBW) children are limited. We investigated the prevalence of metabolic syndrome components in VLBW infants at 2 years of corrected age.

METHODS

We included 38 children, participating in the Neonatal Insulin Replacement Therapy in Europe (NIRTURE) trial, a randomized controlled trial of early insulin therapy in VLBW infants. Metabolic syndrome components were defined as: body mass index SDS >2; blood pressure (systolic and/or diastolic) ≥ 90th percentile; triglycerides ≥ 0.98 mmol/l; high-density lipoprotein (HDL) cholesterol ≤ 1.03 mmol/l; glucose ≥ 5.6 mmol/l.

RESULTS

Two children (5%) had three metabolic syndrome components, 13 children (34%) had two components, and 11 children (29%) one component. 63% had raised blood pressure (prevalence higher in boys), 32% low HDL, and 30% high triglycerides (prevalence lower in early insulin group). In children with body mass index SDS <0, insulin-treated children had higher HDL than children with standard care. Systolic blood pressure was correlated with growth between term and 2 years of corrected age.

CONCLUSIONS

VLBW infants already have a high prevalence of metabolic syndrome components at 2 years of corrected age. Early insulin treatment could have long-term benefits for some of these components.

Procollagen type I N-terminal peptide in preterm infants is associated with growth during the first six months post-term

OBJECTIVE

To identify growth-related collagen and bone parameters in small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) preterm infants during the first six months post-term. In SGA preterm infants, increased growth and decreased bone acquisition, which we demonstrated previously, may be reflected by these markers.

DESIGN

Observational study within a randomized controlled trial.

PATIENTS

Thirty-three SGA (weight, length or both at birth <-2 SDS) and 98 AGA preterm infants (gestational age [median (IQR)]: 31·1 (1·6) vs 30·3 (2·0) weeks; 72·7% vs 42·9% boys).

MEASUREMENTS

Weight (g), length (cm), procollagen type I N-terminal peptide (PINP; μg/l), urinary helical peptide (UHP; μg/mmol creatinine) and alkaline phosphatase (ALP; U/l) expressed as standard deviation scores (SDS) at term age, three and six months post-term.

RESULTS

Weight and length gain during the first six months post-term and PINP SDS at term age, three months and six months post-term were higher in SGA compared with AGA infants. UHP SDS and ALP SDS were similar in SGA and AGA infants. PINP SDS and UHP SDS at term age and PINP SDS at three months were associated with subsequent weight and length gain until six months post-term.

CONCLUSIONS

Increased growth in SGA compared with AGA preterm infants is reflected by increased collagen type I synthesis during the first six months post-term, suggesting that PINP and UHP correspond with growth in preterm infants. An explanation for decreased bone acquisition of SGA preterm infants may be that increased collagen type I synthesis is not directly followed by increased bone mineralization.

Development of a multiplex real-time PCR assay for the rapid diagnosis of neonatal late onset sepsis

The diagnosis of late onset sepsis (LOS), a severe condition with high prevalence in preterm infants, is hampered by the suboptimal sensitivity and long turnaround time of blood culture. Detection of the infecting pathogen directly in blood by PCR would provide a much more timely result. Unfortunately, PCR-based assays reported so far are labor intensive and often lack direct species identification. Therefore we developed a real-time multiplex PCR assay tailored to LOS diagnosis which is easy-to-use, is applicable on small blood volumes and provides species-specific results within 4h. Species-specific PCR assays were selected from literature or developed using bioinformatic tools for the detection of the most prevalent etiologic pathogens: Enterococcus faecalis, Staphylococcus aureus, Staphylococcus spp., Streptococcus agalactiae, Escherichia coli, Pseudomonas aeruginosa, Klebsiella spp. and Serratia marcescens. The PCR assays showed 100% specificity, full coverage of the target pathogens and a limit of detection (LOD) of ≤10CFUeq./reaction. These LOD values were maintained in the multiplex format or when bacterial DNA was isolated from blood. Clinical evaluation showed high concordance between the multiplex PCR and blood culture. In conclusion, we developed a multiplex PCR that allows the direct detection of the most important bacterial pathogens causing LOS in preterm infants.

Growth in preterm infants until six months postterm: the role of insulin and IGF-I

BACKGROUND/AIMS

Since insulin-like growth factor type I (IGF-I) and insulin regulate growth in term infants, they were studied in relation to nutrient intake and growth until 6 months corrected age (CA) in preterm infants.

METHODS

In 138 preterm infants (51% male, gestational age (expressed as median (IQR)) 30.6 (1.9) weeks, birth weight 1,368 (389) g) weight SDS, length SDS, IGF-I, and insulin were measured at term age, 3 and 6 months CA.

RESULTS

IGF-I and insulin at term age were associated with weight SDS and length SDS at term age and 3 months CA. IGF-I and insulin at 3 months CA were associated with weight SDS and length SDS at 3 and 6 months CA. IGF-I and insulin at term age were negatively associated with gain in weight SDS and gain in length SDS between term age and 6 months CA (IGF-I: β = -1.03, 95% CI -1.65;-0.41, p = 0.001 and β = -0.78, 95% CI -1.32;-0.23, p = 0.005; insulin: β = -0.19, 95% CI -0.37;-0.01, p = 0.044 and β = -0.18, 95% CI -0.35;-0.01, p = 0.035). Nutrient intake was not associated with IGF-I or insulin.

CONCLUSIONS

The present study suggests that IGF-I and insulin are important growth regulators in preterm infants until 6 months CA, independent of nutrient intake.

Higher vitamin D intake in preterm infants fed an isocaloric, protein- and mineral-enriched postdischarge formula is associated with increased bone accretion

During the first half of infancy, bone accretion in preterm infants fed an isocaloric, protein- and mineral-enriched postdischarge formula (PDF) is higher compared with those fed term formula (TF) or human milk (HM). This may be related to higher protein, calcium, phosphorus, and vitamin D intakes. This study investigated serum calcium, phosphate, and 25-hydroxyvitamin D [25(OH)D] in relation to bone mineral content (BMC) in PDF-, TF-, and HM-fed preterm infants between term age (40 wk postmenstrual age) and 6 mo corrected age (CA). Between term age and 6 mo CA, 52 preterm infants were fed PDF (per 100 mL: 67 kcal, 1.7 g protein, 65 mg calcium, 38 mg phosphorus, 56 IU vitamin D), 41 were fed TF (per 100 mL: 67 kcal, 1.47 g protein, 50 mg calcium, 30 mg phosphorus, 48 IU vitamin D), and 46 were fed HM. Serum calcium, phosphorus, and 25(OH)D were measured at term age and at 3 and 6 mo CA. BMC (g) was measured by whole-body dual-energy X-ray absorptiometry at term age and at 6 mo CA. Between term age and 6 mo CA, intakes of calcium, phosphorus, and vitamin D were significantly higher in PDF- compared with TF-fed infants, and PDF-fed infants reached significantly higher serum 25(OH)D concentrations at 6 mo CA (103 ± 24.3 vs. 92.8 ± 15.5 nmol/L, P = 0.003). Between term age and 6 mo CA, increases in serum 25(OH)D were associated with an increase in BMC (β = 0.001; 95% CI: 0.00, 0.003; P = 0.046). In conclusion, during the first 6 mo postterm, higher vitamin D intake and greater increase in serum 25(OH)D concentration in PDF-fed preterm infants were associated with increased bone accretion.

Incidence and risk factors for catheter-associated bloodstream infections in neonatal intensive care

AIM

To determine the incidence and potential novel risk factors for catheter-associated bloodstream infections (CABSI) in neonates.

METHODS

A retrospective study was conducted for infants admitted to the VU University Medical Center neonatal intensive care unit in 2007.

RESULTS

One hundred and ninety six infants with a total of 369 central catheters were included. The CABSI rate was 18.1 infections/1000 catheter-days (95% CI 13.7-23.8) according to adjusted criteria used by the Centers for Disease Control and Prevention prior to 2008. Umbilical catheters had a higher infection rate than nonumbilical central catheters: rate ratio (rate ratio 2.4, 95% CI 1.2-4.9). Longer umbilical catheter dwell-time also increased infection rate (p < 0.05). Gestational age, birth weight, duration of parenteral nutrition and the administration of all-in-one feeding mixture versus parenteral nutrition administered in separate components were not related to infection rate in multivariate analysis.

CONCLUSION

Of all catheter types, umbilical catheters carried the highest infection rate. Longer umbilical catheter dwell-time also increased infection rate. The present data suggest that the impact of gestational age and birth weight on infection rate is mainly due to a prolonged hospital stay. The composition, way of preparation and duration of parenteral nutrition did not seem to influence infection rate.

Urine gonadotropin and estradiol levels in female very-low-birth-weight infants

BACKGROUND

The postnatal activation of the hypothalamic-pituitary-gonadal axis is more exaggerated in preterm than in full-term born infants and may be important for future reproductive function.

AIM

The objective of this study was to investigate the postnatal activation of the hypothalamic-pituitary-gonadal axis in female very-low-birth-weight infants.

STUDY DESIGN

We performed serial measurements of gonadotropin and estradiol levels in urine samples of female very-low-birth-weight infants collected at 1 and 4weeks postnatal age, at 32weeks postmenstrual age, at expected date of delivery and at the corrected age of three and six months.

SUBJECTS

Twenty-two very-low-birth-weight infants (gestational age 25.4-30.1weeks), participating in the Neonatal Insulin Replacement Therapy in Europe trial, were included in this study.

OUTCOME MEASURES

Gonadotropin and estradiol levels were measured in serial urine samples.

RESULTS

Longitudinal analysis shows that after birth FSH and LH levels increase until 32weeks postmenstrual age (4weeks postnatal age) and then decrease until 3months corrected age (26weeks postnatal age). Estradiol levels decrease from 28weeks postmenstrual age (1week postnatal age) until 6months corrected age (39weeks postnatal age).

CONCLUSIONS

Serial urine sampling for measurement of gonadotropin and estradiol levels provides an accurate description of the postnatal activation of the hypothalamic-pituitary-gonadal axis in very-low-birth-weight girls. Levels of FSH and LH peak at a mean postmenstrual age of 32weeks (postnatal age of 4weeks) whereas estradiol levels are highest shortly after birth.

Small-for-gestational-age preterm-born infants already have lower bone mass during early infancy

BACKGROUND

In preterm-born infants, low birth weight and diminished bone accretion deteriorate peak bone mass. Whether low birth weight is already associated with decreased bone mass during infancy is unknown.

OBJECTIVE

To study the effect of birth weight on bone accretion between term age (40 weeks postmenstrual age) and six months post-term in preterm-born infants.

DESIGN

In 139 preterm-born infants (51% male, gestational age 30.3±1.5 weeks, birth weight 1341±288g) weight and whole-body bone mineral content (BMC, gram) were measured at term age and six months post-term. At birth, infants were small-for-gestational-age (SGA, n=33, weight and/or length<-2 SDS) or appropriate-for-gestational-age (AGA, n=98, weight and length≥-2 SDS).

RESULTS

At term age and six months post-term, BMC adjusted for gender and gestational age was lower in SGA than AGA infants (term age: 38.1±9.5 versus 48.6±10.1g, β=-0.26, 95% CI -0.37; -0.16, p<0.001; six months: 130.1±25.7 versus 145.4±22.9g, β=-0.16, 95% CI -0.25; -0.08, p<0.001). At six months post-term, BMC remained lower in SGA infants after adjustment for actual weight and length. Between term age and six months post-term, BMC gain adjusted for gender and gestational age was lower in SGA than AGA infants (91.7±22.8 versus 98.2±20.7g; β=-0.12, 95% CI -0.24; -0.003, p=0.044). BMC gain remained lower in SGA infants after adjustment for weight and length gain.

CONCLUSION

The first six months post-term, SGA preterms have lower bone accretion, independent of body size, suggesting that prenatal conditions for bone accretion cannot be replicated postnatally.

Pharmacokinetics and pharmacodynamics of medication in asphyxiated newborns during controlled hypothermia. The PharmaCool multicenter study

Background

In the Netherlands, perinatal asphyxia (severe perinatal oxygen shortage) necessitating newborn resuscitation occurs in at least 200 of the 180–185.000 newly born infants per year. International randomized controlled trials have demonstrated an improved neurological outcome with therapeutic hypothermia. During hypothermia neonates receive sedative, analgesic, anti-epileptic and antibiotic drugs. So far little information is available how the pharmacokinetics (PK) and pharmacodynamics (PD) of these drugs are influenced by post resuscitation multi organ failure and the metabolic effects of the cooling treatment itself. As a result, evidence based dosing guidelines are lacking. This multicenter observational cohort study was designed to answer the question how hypothermia influences the distribution, metabolism and elimination of commonly used drugs in neonatal intensive care.

Methods/Design

Multicenter cohort study. All term neonates treated with hypothermia for Hypoxic Ischemic Encephalopathy (HIE) resulting from perinatal asphyxia in all ten Dutch Neonatal Intensive Care Units (NICUs) will be eligible for this study. During hypothermia and rewarming blood samples will be taken from indwelling catheters to investigate blood concentrations of several antibiotics, analgesics, sedatives and anti-epileptic drugs. For each individual drug the population PK will be characterized using Nonlinear Mixed Effects Modelling (NONMEM). It will be investigated how clearance and volume of distribution are influenced by hypothermia also taking maturation of neonate into account. Similarly, integrated PK-PD models will be developed relating the time course of drug concentration to pharmacodynamic parameters such as successful seizure treatment; pain assessment and infection clearance.

Discussion

On basis of the derived population PK-PD models dosing guidelines will be developed for the application of drugs during neonatal hypothermia treatment. The results of this study will lead to an evidence based drug treatment of hypothermic neonatal patients. Results will be published in a national web based evidence based paediatric formulary, peer reviewed journals and international paediatric drug references.

Trial registration

NTR2529.

Birth Weight Corrected for Gestational Age is Related to the Incidence of Down's Syndrome Pregnancies

Three recent studies reported that early depletion of the primordial follicle pool is likely to be an independent risk factor for Down's syndrome pregnancies. The size of the primordial follicle pool at birth is determined by oogenesis and by the rate of follicle atresia during the intra uterine period. Since intra uterine growth retardation was reported to be associated with a significantly reduced primordial follicle pool at birth, we investigated the possibility of a relation between low birth weight for gestational age and the risk of a Down's syndrome pregnancy. In a case control study, 95 women with a history of a Down's syndrome pregnancy and 85 controls provided information on their own birth weight and length of gestation. Birth weight standard deviation scores, indicating the difference in birth weight from a reference group, were significantly lower in Down's syndrome mothers than in controls. These findings illustrate that the risk of a Down's syndrome pregnancy is related to a low birth weight corrected for gestational age, possibly by a causal relation between intra uterine growth retardation and the size of the primordial follicle pool