To examine the risk of mortality and major morbidities in extremely preterm multiple gestation infants compared with singletons over time.METHODS: This is a retrospective study of 15 402 infants born #27 weeks' gestation, admitted to NICUs in the Australian and New Zealand Neonatal Network from 1995 to 2009. Mortality and major morbidities were compared between singletons and multiples across three 5-year epochs.RESULTS: Extreme preterm multiples were more likely to have lower birth weight; higher maternal age; and higher rates of assisted conception, antenatal steroid use, and cesarean delivery compared with singletons. The mortality rate was significantly higher in multiples compared with singletons even as there was a trend of decreasing gestational-age stratified mortality in multiples over the time period investigated. The rates of major morbidities or composite adverse outcomes were not different between multiples and singletons across all epochs. The adjusted odds ratio (AOR) for mortality in multiples was significantly higher in multiples compared with singletons (AOR 1.20, 95% confidence interval [CI] 1.08-1.34). There were no differences in the adjusted odds for poor outcomes in multiples compared with singletons in the most recent epoch: mortality (AOR 1.00, 95% CI 0.84-1.19), major morbidity (0.95, 95% CI 0.81-1.10), and composite adverse outcome (0.96, 95% CI 0.83-1.11).CONCLUSIONS: Over the 15-year period, the odds for mortality in extremely preterm NICU infants of multiple gestation was significantly higher compared with singletons. The adjusted odds of poor outcomes in multiples were not significantly different from that of singletons in the most recent epoch. WHAT'S KNOWN ON THIS SUBJECT:Studies on the risk of mortality and morbidities of extremely preterm infants of multiple gestation births have shown inconsistent results. Perinatal antecedents, admission status and severity of illness after birth can adversely affect outcomes of the extremely premature infants.WHAT THIS STUDY ADDS: Preterm multiple gestation infants have increased risk of mortality but similar risk of major morbidities compared with singletons. Outcomes improved over time and all adverse outcomes, including mortality, were comparable between multiples and singletons in the most recent 5-year epoch.

FiO2 on stabilisation post-surfactant treatment has a weak predictive value and may not be adequate to be used as sole criteria to extubate to CPAP prior to transport. FiO2 at stabilisation should be included as an eligibility criteria for a randomised trial of INSURE during retrieval, but other clinical assessments are needed.

Consultations for infantile hypercalcaemia (IIH) have increased at Sydney Children's Hospital since guidelines for vitamin D 3 supplementation during pregnancy were introduced in 2006. Recent nationwide shortages of lowcalcium formula (LCF) suggest this problem may be widespread. CYP24A1 mutations have been identified as a potential cause of IIH.To determine if IIH is occurring more commonly, deidentified, first-measured serum calcium from all infants <6 months (n=5796) measured in our laboratory, were grouped by years 2005-2007 (n=1516), 2008-2010 (n=1945) and 2011-2013 (n=2335). In addition, we analysed 13 infants treated by our department for idiopathic infantile hypercalcaemia (IIH) from 2011-2013.Rates of hypercalcaemia (>2.75mmol/L) increased from 2011 (1.1% vs 1.3% vs 8.7%, χ 2 P<0.001). Rates of hypocalcaemia (<2.25mmol/L) fell steadily (42.4% vs 32.3% vs 24.8% %, χ 2 P<0.001). Twelve mothers of our 13 infants with IIH received antenatal vitamin D 3 supplementation. One infant also received 400 units/day Vitamin D 3 post-natally. At diagnosis, median age was 13 days (range 4-50), 77% were breast-fed, 54% were symptomatic and 25% had nephrocalcinosis. Median initial calcium was 3.00mmol/L (range 2.84-4.03) and phosphate 2.04mmol/L (1.1-3.33). PTH was not elevated (median 1.0pmol/L [<0.3-3.1]), urinary calcium: creatinine ratio not suppressed (median 2.3, [0.4-9]), 25OHVitD low-normal (median 44nmol/L [17-218]) and 1,25(OH) 2 VitD elevated (median 232pmol/L [64-720]), in keeping with an abnormality in CYP24A1. In 7/10 infants with data available, treated with LCF for median 95 days (range 25-310), median PTH rose to 17.1pmol/L ([8.2-49.3], P=0.02) with a trend to lower 25OHVit D (median 23nmol/L [<10-108], P=0.09) despite continued high-normal calcium levels (median 2.66mmol/L [2.11-2.75]).Concurrent changes in rates of hyper and hypo-calcaemia suggest antenatal vitamin D 3 supplementation as an aetiological factor. IIH was associated with significant morbidity, including symptomatic hypercalcaemia and nephrocalcinosis. Treatment with LCF prevented further symptomatic hypercalcaemia, but resulted in elevated PTH. The biochemistry of our patients with IIH raises variations in Vitamin D metabolism or calcium set-point as potential associated factors.