Observational study on the neonatal outcome during the COVID-19 pandemic in Germany.

AIM: We aimed to determine stillbirth, preterm birth, perinatal complications, and the developmental outcome of children born preterm during the COVID-19 pandemic in Germany. METHODS: National data from the perinatal survey of preterm and term infants born in 2017-2020 between 22 March and 31 December were evaluated. Neurodevelopment of preterm infants at 2 years corrected age was tested with the Parent Report of Children's Abilities-Revised questionnaire and by clinical testing with Bayley scales, either before or during the COVID-19 pandemic. Statistical significance was calculated using a Pearson's chi-square-independence test and a linear regression model. RESULTS: In 2020, there was an increase of stillbirths of 0.02% (p = 0.01) and a decrease in preterm births by 0.38% (p < 0.001). No changes were found in a representative subgroup of infants with regard to neurodevelopmental scores (mental developmental index and psychomotor developmental index) or in parent survey data (non-verbal cognition scale and language development scale). CONCLUSION: Increasing rates of stillbirths and decreasing preterm births in Germany were observed. Existing networks might stabilise neurodevelopment of preterm infants during the COVID-19 pandemic.

Blood group AB increases risk for surgical necrotizing enterocolitis and focal intestinal perforation in preterm infants with very low birth weight.

Necrotizing enterocolitis (NEC) and focal intestinal perforation (FIP) are two of the most common emergencies of the gastrointestinal tract in preterm infants with very low birth weight (VLBW, birth weight < 1500 g). Identification of risk factors among these children is crucial for earlier diagnosis and prompt intervention. In this study, we investigated a relationship between ABO blood groups and the risk for surgical NEC/FIP. We genotyped the ABO locus (rs8176746 and rs8176719) in VLBW infants enrolled in a prospective, population-based cohort study of the German Neonatal Network (GNN). Of the 10,257 VLBW infants, 441 (4.3%) had surgical NEC/FIP. In univariate analyses, the blood group AB was more prevalent in VLBW infants with surgical NEC/FIP compared to non-AB blood groups (OR 1.51, 95% CI 1.07-2.13, p = 0.017; absolute risk difference 2.01%, 95% CI 0.06-3.96%). The association between blood group AB and surgical NEC/FIP was observed in a multivariable logistic regression model (OR of 1.58, 95% CI 1.10-2.26, p = 0.013) as well. In summary, our study suggests that the risk of surgical NEC and FIP is higher in patients with blood group AB and lower in those having non-AB blood groups.

Gut Dysbiosis With Bacilli Dominance and Accumulation of Fermentation Products Precedes Late-onset Sepsis in Preterm Infants.

BACKGROUND: Gut dysbiosis has been suggested as a major risk factor for the development of late-onset sepsis (LOS), a main cause of mortality and morbidity in preterm infants. We aimed to assess specific signatures of the gut microbiome, including metabolic profiles, in preterm infants <34 weeks of gestation preceding LOS. METHODS: In a single-center cohort, fecal samples from preterm infants were prospectively collected during the period of highest vulnerability for LOS (days 7, 14, and 21 of life). Following 16S rRNA gene profiling, we assessed microbial community function using microbial metabolic network modeling. Data were adjusted for gestational age and use of probiotics. RESULTS: We studied stool samples from 71 preterm infants with LOS and 164 unaffected controls (no LOS/necrotizing enterocolitis). In most cases, the bacteria isolated in diagnostic blood culture corresponded to the genera in the gut microbiome. LOS cases had a decelerated development of microbial diversity. Before onset of disease, LOS cases had specific gut microbiome signatures with higher abundance of Bacilli (specifically coagulase-negative Staphylococci) and a lack of anaerobic bacteria. In silico modeling of bacterial community metabolism suggested accumulation of the fermentation products ethanol and formic acid in LOS cases before the onset of disease. CONCLUSIONS: Intestinal dysbiosis preceding LOS is characterized by an accumulation of Bacilli and their fermentation products and a paucity of anaerobic bacteria. Early microbiome and metabolic patterns may become a valuable biomarker to guide individualized prevention strategies of LOS in highly vulnerable populations.

Regulatory T cell frequencies are increased in preterm infants with clinical early-onset sepsis.

The predisposition of preterm neonates to invasive infection is, as yet, incompletely understood. Regulatory T cells (Tregs ) are potential candidates for the ontogenetic control of immune activation and tissue damage in preterm infants. It was the aim of our study to characterize lymphocyte subsets and in particular CD4(+) CD25(+) forkhead box protein 3 (FoxP3)(+) Tregs in peripheral blood of well-phenotyped preterm infants (n = 117; 23 + 0 - 36 + 6 weeks of gestational age) in the first 3 days of life in comparison to term infants and adults. We demonstrated a negative correlation of Treg frequencies and gestational age. Tregs were increased in blood samples of preterm infants compared to term infants and adults. Notably, we found an increased Treg frequency in preterm infants with clinical early-onset sepsis while cause of preterm delivery, e.g. chorioamnionitis, did not affect Treg frequencies. Our data suggest that Tregs apparently play an important role in maintaining maternal-fetal tolerance, which turns into an increased sepsis risk after preterm delivery. Functional analyses are needed in order to elucidate whether Tregs have potential as future target for diagnostics and therapeutics.

Length and weight of very low birth weight infants in Germany at 2 years of age: does it matter at what age they start complementary food?

BACKGROUND/OBJECTIVES: We analysed at what age parents start complementary food in very low birth weight infants, determined risk factors for early introduction of complementary food (post-term age) and analysed whether the age at introduction of complementary food influences height or weight at 2 years of age. SUBJECTS/METHODS: Parents of premature infants born in 2009-2011 answered questionnaires regarding introduction of complementary food in the first year of life (N=2262) and were followed up at a post-term age of 2 years (N=981). Length and weight were compared with full-term infants from the KiGGs study. Logistic and linear regression analyses were conducted to study predictors for early introduction of complementary food and the influence of age at introduction of complementary food on later height and weight. RESULTS: Average age at introduction of complementary food was 3.5 months post-term age. The lower the gestational age at birth, the earlier (post-term age) vegetables and meat were introduced. Age at introduction of complementary food was influenced by intrauterine growth restriction, gestational age at birth, maternal education and a developmental delay perceived by the parents. Length and weight at a post-term age of 2 years was not negatively influenced by early introduction of complementary food. CONCLUSIONS: VLBW infants are introduced to complementary food on average before a post-term age of 4 months. There was no negative effect of early introduction of complementary food on height and weight at 2 years of age.

Influence of smoking and alcohol during pregnancy on outcome of VLBW infants.

BACKGROUND: Nicotine and alcohol consumption have been associated with premature delivery and adverse neonatal outcome. We wanted to analyze the influence of self-reported nicotine and alcohol consumption on outcome of VLBW infants. MATERIAL AND METHODS: In an ongoing multicenter study 2475 parents of former very low birth weight (VLBW) infants born between January 2009 and December 2011 answered questionnaires about maternal smoking habits and alcohol consumption during pregnancy. 2463 (99.5%) completed questions on alcohol consumption and 2462 (99.5%) on smoking habits. These infants were stratified to reported maternal smoking and alcohol consumption during pregnancy. We compared the reasons for premature delivery, neonatal outcome and parental reports on bronchitis during the first year of life, as well as growth and development at age 2 years to pregnancy exposure. RESULTS: In nicotine exposed infants intrauterine growth restriction (31 vs. 21%, p<0.01), a birth weight below the 10th percentile (26 vs. 17%, p<0.01) and placenta abruption (9.2 vs. 5.8%, p<0.05) was seen more often. Premature rupture of membranes (24 vs. 30%, p<0.05) or HELLP syndrome (6 vs. 11%, p<0.01) was less frequent. A birth weight below the 3rd percentile was seen more frequently in mothers with reported alcohol consumption (13 vs. 6%, p<0.05). We noted an increased rate of BPD and ROP if mothers reported smoking during pregnancy (p<0.05). Growth parameters and scores on Bayley Sscales of infant development at age 2 years did not differ. CONCLUSION: Smoking during pregnancy results in a high rate of growth restricted VLBW infants. Prenatal exposition to nicotine seems to increase postnatal complications such as BPD und ROP.

Pregnancy risk factors for very premature delivery: what role do hypertension, obesity and diabetes play?

PURPOSE: Very premature delivery is a major cause of infant morbidity and mortality. Obesity, diabetes and pregnancy hypertension are known risk factors for pregnancy complications. The study aimed to scrutinize differences of pregnancy complications in a cohort of very premature deliveries compared to a national group. METHODS: In a multicenter study performed between January 2009 and December 2010 including 1,577 very low birth weight (VLBW) infants, we compared parental reported pregnancy problems of VLBW infants with a national cohort (KIGGS). We compared reported pregnancy complications to reasons for premature delivery and neonatal outcome within the group of VLBW infants. RESULTS: While parents of the national cohort reported pregnancy-induced hypertension in 8 %, parents of VLBW infants reported this complication more frequently (27 %). Mothers of the national cohort were significantly younger (1 year), suffered less from obesity, anaemia, diabetes. Regression analysis showed that hypertension (OR = 5.11) and advanced maternal age (OR = 1.03) increased the risk for premature birth. Women with hypertension were likely to experience a clinically indicated premature delivery, had more VLBW infants with a moderate growth restriction, but less multiples and their infants had less intraventricular haemorrhages grade 3 or 4. Otherwise, neonatal outcome was correlated with gestational age but not with the pregnancy complications diabetes, hypertension or obesity. CONCLUSION: Premature birth seems to be correlated to gestational hypertension and associated problems in about » of VLBW infants. Further studies should focus on preventing and treating gestational hypertension to avoid premature delivery and associated neonatal morbidity.

Major contributors to hospital mortality in very-low-birth-weight infants: data of the birth year 2010 cohort of the German Neonatal Network.

The German Neonatal Network (GNN) is a prospective cohort study with the focus on long term development of very-low-birth-weight infants. It was the aim of this study to determine detailed information on causes of mortality in the GNN birth cohort 2010.Major contributors to hospital mortality were recorded by the attending neonatologists for the cohort of very-low-birth-weight (VLBW) infants born in centres of the German Neonatal Network (GNN) in 2010. The data quality was approved by on-site monitoring.2 221 VLBW infants were born in GNN centres in 2010, and death occurred in 221 infants. Male infants carried a higher risk than females (58.8% males among non-survivors vs. 51.7% among survivors, p=0.047). In 11 infants, the major contributor to death was not determined by the attending neonatologist. In 25 infants born at the limit of viability, comfort palliative care was primarily initiated and 14 infants had lethal malformations. The majority of non-survivors suffered from inflammatory diseases including sepsis- or necrotizing enterocolitis (NEC)-associated death (n=56). Respiratory pathology was a major contributor to death in 65 infants including 11 infants who died from pulmonary haemorrhage.Potentially preventable complications of preterm birth such as sepsis, NEC and pulmonary haemorrhage predominate the major contributors to mortality in the GNN 2010 cohort. In order to decrease the rate of these associated deaths, future trials should focus on prophylaxis and therapy optimization strategies for these outcomes.

Galectin-3 in cord blood of term and preterm infants.

In recent years galectin-3 has gained attention as a signalling molecule, mainly in inflammatory diseases. Data on galectin-3 expression in neonates, however, are limited, and expression of this lectin in cord blood has not yet been reported. The aim of this study was to determine galectin-3 levels in cord blood of term and preterm neonates as well as galectin-3 levels in cord blood of term neonates after stimulation with the prevalent pathogen Streptococcus agalactiae. Cord blood samples were incubated for 24 h and galectin-3 levels were assessed by enzyme-linked immunosorbent assay. There is a positive correlation between gestational age and galectin-3 levels in cord blood. Expression of galectin-3 is significantly higher in cord blood of small-for-gestational-age infants compared to appropriate-for-gestational-age infants. Stimulation with an invasive but not with a colonizing strain of S. agalactiae induced expression of galectin-3. Galectin-3 is expressed constitutively in cord blood of neonates and seems to play a role in the innate immunity of this population.

Pandemic A/H1N1(2009) influenza infections in very-low-birth-weight infants--a case series from the German Neonatal Network.

6 cases of clinical influenza A/H1N1(2009) infections were reported within the multi-center German Neonatal Network (GNN) during the primary hospital stay in the pandemic season 2009/2010 and 2010/2011. Clinical symptoms varied from transient hyperthermia to apnea and severe respiratory distress. 1 fatal course with systemic inflammatory response after perinatal transmission of A/H1N1(2009) was observed. Oseltamivir treatment in 3/6 infants was without side effects. The reported cases have major implications for the management of VLBW infants: i) fatal courses after perinatal transmission are possible, ii) postnatal A/H1N1(2009) infection may result in life threatening events at a time when the infant is otherwise stable, iii) vaccination should be recommended for parents and medical staff to avoid nosocomial transmission, iv) more data are needed on the benefit and harm of antiviral drugs in preterm infants, v) neonatologists should suspect A/H1N1(2009) infection when unexplained sepsis-like or respiratory symptoms occur in VLBW infants.

Polymorphisms of interleukin 18 in the genetics of preterm birth and bronchopulmonary dysplasia.

Interleukin 18 (IL-18) is an important cytokine and involved in the pathogenesis and genetics of many diseases. The authors studied two different populations of preterm infants to test whether polymorphisms within IL-18 are in association with prematurity itself or with typical pulmonary disease or measurements seen in preterm infants, such as bronchopulmonary dysplasia, pneumothoraces and application of surfactant, inhalation or mechanical ventilation. Whereas the first population of 228 preterm infants showed strong association of IL-18 with preterm birth (p<0.001), this was not confirmed in the second population of 346 preterm infants. In addition, no association with any lung condition of prematurity was observed. The authors conclude that IL-18 does not play an important role in the genetics of preterm birth nor in the development of bronchopulmonary dysplasia and other lung complications in preterm infants. Caution must be taken in the interpretation of the results of genetic association studies performed in one population.

Surfactant without intubation in preterm infants with respiratory distress: first multi-center data.

BACKGROUND: Recently in a report of a single center a method has been described to apply surfactant via a thin endotracheal catheter to very low birth weight infants spontaneously breathing with nasal continuous positive airway pressure. We now analyzed available multicenter data. PATIENTS AND METHODS: In a multicenter study investigating genetic risk factors, clinical and outcome data and data of antenatal and postnatal treatment of infants with a birth weight below 1,500 g were prospectively recorded. The measures of infants treated with the new method of surfactant application were compared to those of infants who received standard care. The analysis was restricted to infants with a gestational age below 31 weeks (n=1,541). RESULTS: 319 infants were treated with the new method and 1,222 with standard care. The need for mechanical ventilation during the first 72 h (29% vs. 53%, p<0.001), the rate of bronchopulmonary dysplasia defined as oxygen at 36 weeks of postmenstrual age (10.9 % vs. 17.5%, p=0.004) and the rate of death or bronchopulmonary dysplasia were significantly lower in the treatment group than in the standard care group. Surfactant, theophyllin, caffeine and doxapram were significantly more often and analgetics, catecholamines and dexamethasone were significantly less frequently used in the treatment group. CONCLUSIONS: A new method of surfactant application was associated with a lower prevalence of mechanical ventilation and better pulmonary outcome. A prospective controlled trial is required to determine whether this approach is superior to standard care.

Polymorphisms in the Renin-Angiotensin system and outcome of very-low-birthweight infants.

BACKGROUND: The insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE-ins/del) and the angiotensin II type 1 receptor 1166A/C polymorphism (ATR1166A/C) were reported to be associated with several unfavorable outcome parameters in preterm infants like bronchopulmonary dysplasia, persistent ductus arteriosus and impaired insulin sensitivity. OBJECTIVE: To confirm the above-mentioned associations in a large cohort of very-low-birthweight (VLBW) infants. METHOD: Clinical data of VLBW infants were prospectively recorded. The ACE-ins/del polymorphism and the ATR1166A/C polymorphism were determined by polymerase chain reaction in 1,209 and 1,168 infants, respectively. RESULTS: There was no significant association between ACE-ins/del or ATR1166A/C genotype and outcome parameters (death, intraventricular hemorrhage, sepsis, bronchopulmonary dysplasia, ventilation, supplemental oxygen at discharge, postnatal treatment with insulin, surgery for intestinal perforation/necrotizing enterocolitis/retinopathy of prematurity/persistent ductus arteriosus. CONCLUSION: Both known functional polymorphisms of the renin-angiotensin system do not seem to be associated with the outcome of VLBW infants.

[Impact of assisted reproduction on obstetrics and neonatology]. / Einfluss der assistierten Reproduktion auf Geburtshilfe und Neonatologie.

BACKGROUND: In industrialised countries, 1-4% of all children are born as a result of assisted reproductive therapies (ART), such as IVF and ICSI. Possible associations of these ARTs with obstetric and neonatal risk constellations are analysed critically in the context of this review. METHODS: A selective literature search was conducted to examine the influence of ART on obstetric and neonatal aspects. RESULTS: Multiple gestations, occurring more frequently after ART, are of special significance with regard to their associated risks. In comparison to spontaneous pregnancies, singleton gestations after ART are associated with higher rates of complications, such as preeclampsia, prematurity, low birth weight, foetal malformations and a higher rate of Caesarean sections. Although causal associations between extracorporeal fertilisation methods and health risks for mothers and infants in singleton pregnancies cannot be ruled out, these complications are rather attributed to the underlying causes of infertility than to the methods of assisted reproduction themselves. CONCLUSIONS: Pregnancies after ART are to be regarded as risk constellations with a need for closer surveillance during gestation - irrespective of the number of developing foetuses. Couples seeking advice about infertility should be informed in detail before the onset of ART.

Characterisation of the host inflammatory response to Staphylococcus epidermidis in neonatal whole blood.

BACKGROUND: Coagulase-negative staphylococci (CoNS) are the most prevalent pathogens causing late-onset sepsis, and gestational age is the most important risk factor for these infections. OBJECTIVE: To characterise innate immune responses to S epidermidis by assessment of whole blood in vitro cytokine production in a large group of preterm and term infants. RESULTS: The S epidermidis-induced in vitro production of proinflammatory cytokines such as intracytoplasmic interleukin (IL) 6 and tumour necrosis factor alpha in cord blood samples was found to be dependent on gestational age (R = 0.279, 95% CI 0.10 to 0.44, p = 0.002; R = 0.251, 95% CI 0.07 to 0.41, p = 0.005, respectively; n = 121). In contrast, the production of anti-inflammatory cytokines such as IL10 and transforming growth factor beta was not associated with gestational age. When different stimulation strategies were compared, a strong correlation was noted for cytokine responses after lipopolysaccharide and S epidermidis exposure--that is, IL6 (R = 0.431, 95% CI 0.29 to 0.55, p<0.001, n = 161) and IL10 (R = 0.332, 95% CI 0.18 to 0.47, p<0.001, n = 161). In addition, a lower IL6 production was found in supernatants of whole blood cultures infected with a clinically isolated IcaABD-positive (biofilm production) strain compared with a control IcaABD-negative ATCC strain (p = 0.009). CONCLUSIONS: These in vitro data suggest that proinflammatory responses to S epidermidis are dependent on gestational age in preterm infants, whereas the counteracting anti-inflammatory response to S epidermidis may not be directly related to gestational age. Individual host factors may have a role as well as bacterial determinants, such as biofilm production. Further studies are encouraged to investigate the different aspects of innate immune responses to CoNS in vivo.

Interleukin-6-174-genotype, sepsis and cerebral injury in very low birth weight infants.

We investigated the association between the interleukin 6 (IL-6)-174-genotype and unfavorable outcomes in preterm infants since it has been reported that the IL-6-174GG-genotype is associated with increased susceptibility to sepsis, and the IL-6-174CC-genotype is more common in preterm infants with severe intraventricular hemorrhage (IVH). We studied 1206 preterm infants with a birth weight below 1500 g. In contrast to previously published data, the frequency of IVH grade IV, periventricular leukomalacia, ventricular-peritoneal-shunting or death was not different between infants with different IL-6-genotypes: IL-6-174GG (n = 430) 8%, IL-6-174GC (n = 605) 9% and IL-6-174CC (n = 167) 12% (P = 0.2 for IL-6-174CC vs GG + GC). Furthermore, we were not able to confirm previously reported association between sepsis and the IL-6-174GG-genotype. Blood-culture-proven sepsis occurred in 19% of IL-6-174GG-carriers (n = 157), 26% of IL-6-174GC-carriers (n = 193) and 27% of infants carrying the IL-6-174CC-genotype (n = 67). We were not able to confirm previously reported associations between sepsis, cerebral injury and the IL-6-174-genotype in VLBW-infants.

Polymorphisms of genes involved in innate immunity: association with preterm delivery.

An altered inflammatory activity due to functionally relevant polymorphisms of the innate immune system may influence pathways leading to labour and, therefore, impact on the frequency of preterm birth. We examined five polymorphisms of the innate immune system in a large cohort of preterm very-low-birth-weight (VLBW, n = 909) and term-born infants (n = 491) and their mothers (n = 747). The primary outcome was preterm versus term birth. Frequencies of polymorphisms in mothers of term-born infants versus mothers of VLBW infants and term infants versus preterm VLBW infants (singletons) are given. Homozygous CD14-159T: 18.5 versus 21.8% (mothers) and 19.6 versus 21.2% (infants). Homozygous interleukin IL-6-174G: 28.8 versus 38% (P = 0.018, mothers) and 30 versus 32.7% (infants). Homozygous or heterozygous nuclear oligomerization domain NOD2-3020insC: 6.9 versus 6.1% (mothers) and 5.7 versus 5.1% (infants). Heterozygous or homozygous toll-like-receptor TLR2-Arg753Gln: 6.9 versus 6.1% (mothers) and 5.7 versus 5.1% (infants). Homozygous or heterozygous TLR4-896G: 8.1 versus 11.5% (mothers) and 11.6 versus 10.5% (infants). Although the homozygous maternal IL-6-174G genotype was found to be independently associated with preterm delivery in multivariate regression analysis, the incidence of intrauterine infection was not significantly increased in mothers of preterm VLBW-infants, carrying this or other polymorphisms of the innate immune system. The overall influence of the investigated polymorphisms on the development of preterm delivery seems moderate, since only the maternal IL6-174G genotype was associated with preterm birth and none of the polymorphisms were associated with intrauterine infection as the cause of preterm birth.

Immature anti-inflammatory response in neonates.

The inflammatory response plays a major role in the induction of several neonatal diseases. We hypothesize that an imbalance between the pro- and anti-inflammatory response is crucial for the previously shown enhanced production of proinflammatory cytokines in term and preterm infants during infection. To test this hypothesis, we compared the capacity to produce the main anti-inflammatory cytokines IL-10 and TGF-beta in term infants, preterm infants and adults at different levels of synthesis by quantitative real time reverse-transcribed PCR, flow cytometry, as well as enzyme-linked immunoassay. Term and preterm infants showed a profoundly diminished IL-10 mRNA-expression and IL-10 production after stimulation. In addition, the amount of TGF-beta-positive lymphocytes was significantly less in neonates than adults. Furthermore, there was a considerably lower inhibition of production of IL-1alpha, IL-6, IL-8 and TNF-alpha by the use of recombinant IL-10 in term and preterm infants compared with adults. These results demonstrate not only a diminished anti-inflammatory capacity but also a reduced response to anti-inflammatory stimuli in term and preterm infants. From these data we conclude that neonates display an immature compensatory anti-inflammatory response syndrome (CARS) which may predispose preterm infants to harmful effects of proinflammatory cytokines resulting in severe organ sequelae during infection.

Selection pressure for the factor-V-Leiden mutation and embryo implantation.

The factor-V-Leiden mutation is seen in high frequencies in white people, despite its contribution to second-trimester abortion, preterm birth, and deep-vein thrombosis. The reason for its high frequency is not known. We investigated 102 mother-child pairs who had had successful in-vitro fertilisation by intracytoplasmic sperm injection as a model for human implantation. In 90% (9 of 10) of mother-child pairs who carried factor-V-Leiden mutation, the first embryo transfer was successful, compared with 49% (45 of 92) in factor-V-Leiden negative pairs (p=0.018, Fisher's exact test). Furthermore, the median number of unsuccessful transfers was lower in pairs who were positive for the mutation (0, range 0-2) than those who were negative (1, 0-8) (p=0.02, Mann Whitney U test) suggesting that improved implantation rate is an important genetic advantage of the factor-V-Leiden mutation.

Low prevalence of large intraventricular haemorrhage in very low birthweight infants carrying the factor V Leiden or prothrombin G20210A mutation.

UNLABELLED: The influence of genetic factors that increase coagulation on the extension of intraventricular haemorrhage (IVH) in very low birthweight infants has not been studied previously. This study investigated the frequency and effect of the factor V Leiden and prothrombin G20210A mutations in a population-based cohort of 305 preterm infants with a birthweight below 1500 g. The overall prevalence of IVH was similar in infants with (n = 43) and without (n = 262) prothrombotic mutations (18.6% vs 16.4%, respectively). However, infants with prothrombotic mutations had a significantly reduced risk of developing extension to IVH grade II or more [p = 0.023, odds ratio (OR) 0.11, 95% confidence interval (CI) 0.02-0.5]. The carrier state of a factor V Leiden or prothrombin G20210A mutation was still predictive for a low rate of IVH grade II-IV if possible confounding variables were included in a multivariate regression model (OR 0.12; 95%CI: 0.017-0.86). CONCLUSION: The data suggest that the factor V Leiden and prothrombin G20210A mutations lead to improved control of intraventricular bleeding in very low birthweight infants.