Antenatal Steroid Use Research Articles

Hyperglycemia as a risk factor for the development of retinopathy of prematurity

BackgroundHyperglycemia has recently been described as a risk factor for the development of retinopathy of prematurity (ROP), a proliferative vascular disease of the retina that primarily affects premature infants. This study was to evaluate the relationship of hyperglycemia and the development of ROP in premature infants less than 32 weeks gestation.MethodsThis was a retrospective cohort study of all infants less than 32 weeks gestation from 2003–2007 who survived to discharge in our NICU. Demographic data including birthweight, gestational age, Apgar scores, method of delivery, antenatal steroid use, neonatal steroid use, and size for gestational age was collected for each infant. Episodes of sepsis, grade of intraventricular hemorrhage, presence of a patent ductus arteriosus, number of days on the ventilator, and stage of necrotizing enterocolitis were assessed as well as days of hyperglycemia, defined as number of days with whole blood glucose > 150 mg/dl. In addition, the highest stage of ROP was recorded for each infant. A Student’s two tailed t-test or Fisher’s exact test was performed to identify significant clinical risk factors associated with the development of ROP. From this univariate analysis, a multiple logistic regression was performed to determine the effect of hyperglycemia on the development of ROP, adjusting for significant clinical risk factors. Statistical analysis was performed using SAS v.9.2.ResultsUnivariate analysis demonstrated that infants with ROP were of lower birthweight and gestational age, and were affected by a patent ductus arteriosus, neonatal sepsis, intraventricular hemorrhage, have significant lung disease and received postnatal glucocorticoid therapy. Infants with ROP experienced more days with hyperglycemia (7 vs. 2, p = < 0.0001). Using multiple logistic regression analysis to compare no ROP vs. all stages of ROP, gestational age (OR 0.745, 95% CI [0.634, 0.877], p = 0.0004), mean days of hyperglycemia (OR 1.073, 95% CI [1.004, 1.146], p = 0.04), and mean days receiving mechanical ventilation (OR 1.012, 95% CI [1.000, 1.025], p = 0.05) remained significantly associated with ROP after adjusting for other risk factors.ConclusionOur data suggests that hyperglycemia is associated with the development of ROP in premature infants.

Magnesium Sulfate During Anticipated Preterm Birth for Infant Neuroprotection

Advances in medical care of preterm infants, including the widespread use of surfactant and antenatal steroids, and improvements in ventilation management, have increased the survival rates of some of the most vulnerable infants. Yet, the risk of neurologic impairment and long‐term medical complications remains a concern. Recently, the use of magnesium sulfate during anticipated preterm birth has been identified as a potential treatment to reduce adverse neurologic outcomes among preterm infants. This article discusses the use of magnesium sulfate for anticipated preterm birth to reduce neurologic impairment in preterm infants, including current clinical practice guidelines and implications for nurses.

Non-Oliguric Hyperkalemia in Extremely Low Birth Weight Infants

PurposeIt is to examine clinical manifestations, early biochemical indicators, and risk factors for non-oliguric hyperkalemia (NOHK) in extremely low birth weight infants (ELBWI).Materials and MethodsWe collected clinical and biochemical data from 75 ELBWI admitted to Ajou University Hospital between Jan. 2008 and Jun. 2011 by reviewing medical records retrospectively. NOHK was defined as serum potassium ≥7 mmol/L during the first 72 hours of life with urine output ≥1 mL/kg/h.ResultsNOHK developed in 26.7% (20/75) of ELBWI. Among NOHK developed in ELBWI, 85% (17/20) developed within postnatal (PN) 48 hours, 5% (1/20) experienced cardiac arrhythmia and 20% (4/20) of NOHK infants expired within PN 72 hours. There were statistically significant differences in gestational age, use of antenatal steroid, and serum phosphorous level at PN 24 hours, and serum sodium, calcium, and urea levels at PN 72 hours between NOHK and non-NOHK groups (p-value <0.050). However, there were no statistical differences in the rate of intraventricular hemorrhage, arrhythmia, mortality occurred, methods of fluid therapy, supplementation of amino acid and calcium, frequencies of umbilical artery catheterization and urine output between the two groups.ConclusionNOHK is not a rare complication in ELBWI. It occurs more frequently in ELBWI with younger gestational age and who didn't use antenatal steroid. Furthermore, electrolyte imbalance such as hypernatremia, hypocalcemia and hyperphosphatemia occurred more often in NOHK group within PN 72 hours. Therefore, more use of antenatal steroid and careful control by monitoring electrolyte imbalance should be considered in order to prevent NOHK in ELBWI.

Does chorioamnionitis worsen the outcome of preterm infants? A controversial issue

The term chorioamnionitis is used to describe an intrauterine status of infection/inflammation of either mixed fetal-maternal (choriodecidual space) or fetal origin (chorioamniotic membranes, amniotic fluid, umbilical cord). Histological, microbiological, biochemical and clinical criteria are used to define chorioamnionitis. Histopathological examination of the placenta is the gold standard for evaluating antenatal inflammatory processes that might influence fetal development. Chorioamnionitis is the leading cause of very preterm delivery and its incidence increases with decreasing gestational age. Therefore, it contributes to the high morbidity and mortality of infants born prematurely. In the last decades, several studies have been performed to assess a gestation-independent effect of chorioamnionitis on neonatal and long-term outcome with variable results. The discrepancy observed across studies may be attributable to differences in inclusion and exclusion criteria, disease definitions, methods, and whether potential confounding factors such as gestational age were considered. As underlined by several Authors, the increasingly widespread use of antenatal steroids may have contributed to improve neonatal outcome and can therefore partially explain the different results between studies. In the current review we aim to give an overview and synthesis of a vast amount of existing literature on the association between antenatal infection/inflammation and neonatal and long-term outcome.

Mortality and morbidity analysis in neonates supported by invasive mechanical ventilation

Objectives: To evaluate mortality, morbidity, and invasive mechanical ventilation complications in mechanically ventilated neonates in a tertiary care hospital, Istanbul, Turkey. Materials and methods: The neonates followed on invasive mechanical ventilation from January 2008 to December 2009 were included in the study. A chart is formed for each patient to record patient delivery room and clinical data prospectively. Results: The study population consisted of 236 neonates. Eighty-five percent were born at ≤37 completed weeks of gestation (n=201). Fifty-two percent (n=123) were males. The mean gestational age was 31.9±5 weeks. The mean birthweight was 1870.8±921.8 g. Antenatal steroid rate was 13.3% (n=20) in 150 cases born at ≤34 weeks of gestation. Respiratory distress syndrome (n=100, 42,3%), perinatal depression and asphyxia (n=51, 21,6%), and sepsis (n=47, 19.9%) were the commonest indications. Mechanical ventilation related complications (nosocomial infection (n=57), pulmonary hemorrhage (n=30), pneumonia (n=10), pneumothorax (n=9), and atelectasis (n=4)) developed in 33.5% of neonates (n=79). Bronchopulmonary dysplasia was 9.3%, intracranial hemorrhage (≥grade 3) 8.47%, periventricular leukomalacia 5.93%, necrotizing enterocolitis (>stage 2) 0.42%, and retinopathy of prematurity (>stage 2) 2.96%. Mortality rate was 30.17%. Neonates born at <28 weeks of gestation and with birthweight ≤1000 gram had statistically higher mortality rate than the neonates born at ≥28 weeks of gestation and with birth weight >1000 gram (p<0.05, p<0.05, respectively). Conclusions: Low birthweight and low gestational age are important risk factors for neonatal mortality and morbidity. Low frequency of antenatal steroid use may be a contributing factor to increase neonatal mortality and morbidity.

820 Late Preterm Deliveries and Neonatal Outcomes in Multicentre French Regional Perinatal Network

ObjectiveThe objective of the study was to present the neonatal outcomes for late preterm birth by gestational age at 33.34 and 35 weeks in a multicentric neonatal network.Study DesignThis was...

Antenatal corticosteroids trial in preterm births to increase neonatal survival in developing countries: study protocol.

BackgroundPreterm birth is a major cause of neonatal mortality, responsible for 28% of neonatal deaths overall. The administration of antenatal corticosteroids to women at high risk of preterm birth is a powerful perinatal intervention to reduce neonatal mortality in resource rich environments. The effect of antenatal steroids to reduce mortality and morbidity among preterm infants in hospital settings in developed countries with high utilization is well established, yet they are not routinely used in developing countries. The impact of increasing antenatal steroid use in hospital or community settings with low utilization rates and high infant mortality among premature infants due to lack of specialized services has not been well researched. There is currently no clear evidence about the safety of antenatal corticosteroid use for community-level births.MethodsWe hypothesize that a multi country, two-arm, parallel cluster randomized controlled trial to evaluate whether a multifaceted intervention to increase the use of antenatal corticosteroids, including components to improve the identification of pregnancies at high risk of preterm birth and providing and facilitating the appropriate use of steroids, will reduce neonatal mortality at 28 days of life in preterm newborns, compared with the standard delivery of care in selected populations of six countries. 102 clusters in Argentina, Guatemala, Kenya, India, Pakistan, and Zambia will be randomized, and around 60,000 women and newborns will be enrolled. Kits containing vials of dexamethasone, syringes, gloves, and instructions for administration will be distributed. Improving the identification of women at high risk of preterm birth will be done by (1) diffusing recommendations for antenatal corticosteroids use to health providers, (2) training health providers on identification of women at high risk of preterm birth, (3) providing reminders to health providers on the use of the kits, and (4) using a color-coded tape to measure uterine height to estimate gestational age in women with unknown gestational age. In both intervention and control clusters, health providers will be trained in essential newborn care for low birth weight babies. The primary outcome is neonatal mortality at 28 days of life in preterm infants.Trial registrationClinicalTrials.gov. Identifier: NCT01084096

Serum 17 Alpha Hydroxyprogesterone in Normal Full Term and Preterm vs Sick Preterm and Full Term Newborns in a Tertiary Hospital

To determine the variables affecting serum 17 hydroxyprogesterone (17OHP) in neonates born at a tertiary hospital in Mumbai, India. Serum 17OHP was measured in peripheral venous blood between 3rd to 5th day of life by competitive radioimmunoassay and on follow up at 3 mo of age. Serum 17OHP was compared among four groups [full term healthy(FT), full term stressed(FS), preterm healthy(PT), preterm stressed(PS)] by non-parametric tests (Kruskal Wallis (KW) test and Mann- Whitney (MW) test). Pearson's test was used to correlate natural log of serum 17OHP (ln17OHP) with variables like gestational age, birth weight, stress factor, sex, antenatal administration of glucocorticoids to mothers, Apgar score at 5 min and mode of delivery. Linear regression analysis was done using significant variables in Pearson's test to determine best predictors of ln17OHP. The initial median (number of cases, inter-quartile range) serum 17OHP (ng/ml) for the four groups was as follows; FT 8.4 (33, 6-13); PT 20 (36, 11-29.5); FS 34 (29, 26-45) and PS 58 (24, 40.75-76.5) [total N = 122 newborns, p = 0.001]. Pearson's test showed that gestational age, birth weight, stress factor, Apgar score were negatively correlated with 17OHP whereas stress factor, mode of delivery, use of antenatal steroids in mothers were significantly positively correlated. However, stress factor emerged as the most important significant positive predictor (multiple R = 0.643, P = <0.0001). On follow up at 3 mo age, the median 17OHP (N = 73 newborns) had significantly decreased to normal level. Stress due to neonatal illnesses like meconium aspiration, sepsis, birth asphyxia, etc. significantly elevate serum 17OHP and may lead to false positives in newborn screening for congenital adrenal hyperplasia.

Spontaneous intestinal perforation in extremely low birth weight infants: association with indometacin therapy and effects on neurodevelopmental outcomes at 18–22 months corrected age

BackgroundSpontaneous intestinal perforation (SIP) is associated with the use of postnatal glucocorticoids and indometacin in extremely low birth weight (ELBW) infants. The authors hypothesised: 1) an association of SIP with...

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Incidence, risk factors, and treatment of retinopathy of prematurity among very low birth body weight infants

PurposeThis study was conducted to determine the incidence, risk factors, and treatment for retinopathy of prematurity (ROP) among very low birth weight (VLBW) infants. MethodsThis work is a retrospective, observational analysis of all VLBW infants managed at National Taiwan University Hospital from 2002 to 2005. ResultsThe chart data of 96 VLBW infants were reviewed. Seven of the 96 infants (7.3%) were noted to have no ROP, while 18 infants (18.7%) had minor ROP (stage 1 and stage 2 ROP) and 71 infants (74%) had severe ROP (greater than stage 2 ROP). With lower gestational age, lower birth body weight, greater degree of respiratory distress syndrome, prolonged use of oxygen, and without maternal history of antenatal steroid use, the incidence of severe ROP (greater than stage 2) increased significantly (p < 0.001, p < 0.001, p = 0.01, p < 0.001, and p = 0.03, respectively). ConclusionMore severe ROP may correlate with lower gestational age, lower birth body weight, and longer oxygen use. Use of antenatal steroid would decrease the incidence of severe ROP.

What proportion of preterm births (< 34 weeks) are receiving appropriate antenatal corticosteroids and how many might benefit from a rescue dose?

BackgroundMost reports on antenatal steroid use are non-specific in relation to the appropriate dose received.Purpose of studyTo determine what proportion of mothers are receiving an appropriate dose of antenatal corticosteroids...

Healthcare-associated infections in a neonatal intensive care unit in Turkey

To determine the incidence, risk factors, mortality rate, antibiotic susceptibility and causative agents of healthcare-associated infections (HAIs) in the Neonatal Intensive Care Unit. Prospective, cohort. A 38-bed, teaching, referral, neonatal intensive-care unit. All patients in the neonatal intensive care unit who did not have any sign of infection at admission and remained hospitalized for at least 48 hours. The study was conducted between January 2009 and January 2011. Healthcare-associated infection was diagnosed according to the criteria of CDC. Risk factors for HAI were analyzed with univariate and multivariate regression analysis. The incidence of HAI was found to be 16.2%. Blood stream infection was observed as the most common form of HAI (73.2%). The mortality rate was 17.3%. Antenatal steroid use, cesarean section, male gender, low birth weight, parenteral nutrition, percutaneous and umbilical catheter insertion, mechanical ventilation and low Apgar scores were found to be related with HAI (P<0.05). A 10% reduction in infection rate as a consequence of the application of a new total parenteral nutrition guideline was observed. Coagulase negative staphylococci (44. 4%) and Klebsiella pneumoniae (25.9%) were the most common etiologic agents isolated from cultures. Methicillin resistance of coagulase-negative staphylococci and ESBL resistance of Klebsiella pneumoniae were 72% and 44%, respectively. Antenatal steroid was found to be associated with HAI. Newly applied total parenteral nutrition guidelines reduced the attack rate of infection. Efforts should be focused on developing more effective prevention strategies to achieve better outcomes.

Antenatal steroid use and neonatal outcome: United States 2007

Antenatal steroid use has been associated with reduction in the risk of neonatal mortality in meta-analyses of clinical trials. In 2007, a revised US birth certificate offered information on antenatal steroid use in 22 states. The aim of this study was to review the association between antenatal steroid use and neonatal mortality by gestational age categories for preterm infants (<37 weeks) for the United States for the year 2007. Data were obtained from the United States Linked Infant Birth and Death Certificate Public Use Period file for the year 2007. Associations between antenatal steroid use and neonatal death were determined by logistic regression adjusting for potentially confounding variables. There were 245 453 preterm births and 4220 neonatal deaths available for analysis with complete data on antenatal steroid use. The highest prevalence for antenatal steroid use among neonatal intensive care unit admissions (NICU) was 22% in the 26 to 28 week gestational age category, whereas the lowest prevalence was in the 34- to 36-week group at 7%. Following adjustment for potentially confounding variables by logistic regression, the adjusted odds ratios (95% confidence interval) for neonatal mortality (antenatal steroid use versus non-use) ranged from 0.56 (0.46 to 0.67) at 22 to 25 weeks; 0.66 (0.53 to 0.83) at 26 to 28 weeks; 0.69 (0.55 to 0.85) at 29 to 33 weeks and 0.69 (0.47 to 1.01) at 34 to 36 weeks. These data are in accordance with meta-analytical data of randomized clinical trials and network reports on reduction of neonatal mortality with the use of antenatal steroids, and provide support for the use of antenatal steroids for late preterm births.

Multiple Utilization of Surfactant in Neonatology

Surfactant replacement therapy for the treatment of respiratory distress syndrome (RDS) and other respiratory diseases in newborns has become one of the most active research areas in neonatology. This research has resulted in improved survival for preterm babies since becoming a routine treatment in the 1990s. The main characteristics of pulmonary surfactant, including its composition, pool, metabolism, inactivation and immediate effects after administration, are well-established. However, some doubts still remain about the use of exogenous surfactants and must be addressed. The new generation of synthetic surfactants has raised questions regarding the choice of surfactant type, the ideal timing for treatment (prophylactic vs early rescue strategy), the adequate dose and number of doses, new administration routes and the effects of the association between the use of antenatal steroids and the surfactant replacement therapy. There is also controversy surrounding the choice between early surfactant administration and the use of a nasal CPAP as an initial strategy to treat RDS and to reduce bronchopulmonary dysplasia (BPD). This article reviews basic and clinical aspects of surfactant replacement therapy for RDS and other respiratory diseases in newborns. Keywords: Surfactant, respiratory distress syndrome, antenatal steroids, mechanical ventilation, newborn, respiratory insufficiency, bronchopulmonary dysplasia, Alveolar edema, atelectasis/hyperdistention, alveolar expansion

532: ‘Early’ versus ‘late’ 23 week neonatal outcomes

Erol Amon, Thinh Nguyen, Mohamad Al-Hosni, Jeffrey Gavard Saint Louis University, Obstetrics, Gynecology and Women’s Health, Division of Maternal-Fetal Medicine, Saint Louis, MO, Saint Louis University School of Medicine, Department of Pediatrics, Saint Louis, MO, Saint Louis University, Obstetrics, Gynecology and Women’s Health, Saint Louis, MO OBJECTIVE: To determine if there is a survival difference in 23 week neonates delivered ‘early’ (23 0/7 to 23 3/7 weeks) versus ‘late’ (23 4/7 to 23 6/7 weeks). STUDY DESIGN: Records of 126 consecutive live born infants between 23 0/7 and 23 6/7 weeks gestation treated at a single perinatal center over a 10 year period (2000 to 2010) were examined. These babies were divided into early and late 23 week deliveries . Statistical comparisons were made using chi-square and t-tests as appropriate (P .05) with regards to early or late delivery, antenatal steroid use, birthweight, Apgar score, location of delivery, cesarean delivery and neonatal complications and a composite of survival to discharge or first birthday. RESULTS: 72 infants were born ‘early’ and 54 were ‘late’. Overall, 38% of infants in our cohort survived to discharge or their first birthday. Survival was significantly different in the early (25%) versus late (56%) group (p 0.001). Moreover, there was a significant difference in mean birthweight between the two groups, 547 g for early group versus 596 g for the late group (p 0.001). Additionally, birthweight was noted to be an independent factor in predicting survival (p 0.001). The early group was less likely to have received antenatal steroids (43% vs. 65%; p 0.016). There was no difference in race, gender, multiple gestations, mean 1and 5-minute Apgar scores or delivery mode between the two groups. Neonatal outcomes, including RDS, NEC, chronic lung disease were not significantly different between the two groups. Year-by-year trend analysis did not show an improvement over the ten year study period in either group. CONCLUSION: Early 23 week babies have poorer survival compared to late 23 week babies. Despite the advances in obstetric and neonatal care, neither group showed improved survival over the last decade. These data suggest that delaying delivery even one or two days confers a significant survival benefit and that aggressive intervention may be warranted in this gestational age group.

Immune response to Haemophilus influenzae type b conjugate vaccine in preterm infants

Haemophilus influenzae type b (Hib) vaccine became available for use in Japan in December 2008. The aim of the present study was to evaluate the immunogenicity of Hib vaccine in Japanese preterm infants. Serum samples were obtained from 54 preterm infants before the first vaccination and 1 month after the third. Anti-polyribosylribitol phosphate (PRP) antibodies were measured using an enzyme-linked immunosorbent assay method. Antibody positivity was defined as levels >1 µg/mL. Of the 54 preterm infants, 46 (85.2%) achieved antibody levels >1 µg/mL. This compares with the 92.4% reported in full-term infants. The antibody seroconversion rate of infants starting vaccination at 2 months of age was close to being significantly lower than when vaccination was started at 3 months of age (P= 0.060). In addition, the percentage of infants achieving a positive response in the group with a history of antenatal steroid exposure was significantly higher than in those not exposed (P= 0.046). Thus, risk factors for lower Hib antibody concentrations after three doses of vaccine were age at first vaccination and lack of use of antenatal steroids. There is a possibility that perinatal factors and the environment unique to preterm infants are related to their lower antibody positivity rates compared to full-term infants. It may therefore be preferable to modify the proposed immunization schedule.

SNIPPV vs NIPPV: does synchronization matter?

BackgroundUse of nasal intermittent positive pressure ventilation (NIPPV) in the neonatal intensive care unit (NICU) has shown promise with better clinical outcomes in premature neonates. It is not known if synchronization makes a significant clinical impact when using this technique.ObjectiveTo compare clinical outcomes of premature infants on synchronized NIPPV (SNIPPV) vs. NIPPV in the NICU.Design/MethodsRetrospective data were obtained (1/04 to 12/09) of infants who received NIPPV anytime in the NICU. SNIPPV (Infant Star with StarSync) was utilized from 2004–06, while NIPPV (Bear Cub) was used from 2007–09. BPD was defined using the NIH consensus definition. Unadjusted associations between potential risk factors and BPD/death were assessed using the chi-square or Wilcoxon Rank Sum test. Adjusted analyses were performed using generalized linear mixed models, taking into account correlation among infants of multiple gestation.ResultsThere was no significant difference in the mean gestational age and birth weight in the 2 groups: SNIPPV (n=172; 27.0w; 1016g), NIPPV (n=238; 27.7w; 1117g). There were no significant differences in maternal demographics, use of antenatal steroids, gender, multiple births, SGA, or Apgar scores in the 2 groups. More infants in the NIPPV group were given resuscitation in the delivery room (SNIPPV vs. NIPPV: 44.2% vs. 63%, p<0.001). Surfactant use (84.4% vs. 70.2%; p<0.001) was significantly higher in the SNIPPV group. There were no differences in the rate of PDA, IVH, PVL, ROP, and NEC in the 2 groups. After adjusting for the significant variables, use of NIPPV vs. SNIPPV (OR 0.74; 95%CI: 0.42, 1.30) was not associated with BPD/death.ConclusionsThese data suggest that use of SNIPPV vs. NIPPV is not significantly associated with a differential impact on clinical outcomes.

The impact of pre-pregnancy body mass index on the risk of gestational diabetes

Objective: To evaluate the effect of pre-pregnancy body mass index (BMI) on the risk of developing gestational diabetes mellitus (GDM) in a large unselected population. Methods: We performed a case control study using data collected in The Consortium on Safe Labor database. The association between BMI and GDM was evaluated both using BMI weight categories adopted by the National Institute of Health, and separately using BMI as a continuous variable. Multiple logistic regression analyses were used to evaluate the effects of BMI, age, ethnicity, parity, chronic hypertension and antenatal steroid use on the risk of GDM. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to approximate relative risks of GDM. A p value of <0.05 was considered significant. Results: After controlling for other factors, the risk of GDM increased with an increasing BMI across all weight categories. For each 1 kg/m2 increase of BMI the OR of developing GDM was 1.08 (95% CI 1.08–1.09) and for each 5 kg/m2 increase, the OR was 1.48 (95% CI 1.45–1.51). Conclusions: GDM is a multifactorial disorder and pre-pregnancy BMI plays an important role in that risk. Modest changes in pre-pregnancy BMI may decrease the risk of GDM substantially.

Renal function, renal volume, and blood pressure in infants with antecedent of antenatal steroids

Steroids have been used for more than 20 years in preterm infants to induce pulmonary maturity; however, some long-term effects have been reported, such as insulin resistance and elevation of blood pressure. The aim of our study was to compare renal volume, renal function, and blood pressure in infants between 12-36 months of age with and without antecedent of antenatal steroid treatment. This was a cross-sectional study comprised of three groups of infants (n = 30, respectively): preterm infants with and without antecedent of receiving antenatal steroids, respectively, and full-term infants. Blood pressure, renal volume, glomerular filtration rate, and tubular function were measured. Blood pressure and cystatin C levels and glomerular filtration rate were higher in both groups of preterm infants than in the control group (p < 0.01). However, no difference in any of the tested variables between the steroid and non-steroid group of preterm infants. Renal volume was similar in preterm and control infants. Based on these results, we conclude that prematurity independent of antenatal steroid use is associated with higher cystatin C and blood pressure levels and a higher glomerular filtration rate in infants between 12-36 months of age.