Excess risk of mortality in very low birthweight triplets: a national,population based study

BACKGROUND: Neonatal morbidity and mortality differ between singletons, twins, and triplets. OBJECTIVE: To evaluate whether plurality is associated with excess risk of neonatal morbidity and poor outcome (death, chronic lung disease, or adverse neurological findings) in very low birthweight (VLBW) infants from a national, population based cohort. METHODS: The Israel national VLBW infant database has prospectively collected extensive perinatal and neonatal data on all liveborn VLBW infants since 1995. The study sample (n = 5594) consisted of all singletons (n = 3717) and all complete sets of twins (n = 1394) and triplets (n = 483) born during 1995-1999. To account for differences in case-mix, both univariate and multivariate comparisons that included confounding variables such as antenatal steroid treatment and mode of delivery were performed for each of the outcome variables. RESULTS: There was a small inverse correlation between gestational age (GA) and birth weight (BW) and the number of fetuses (singletons: GA 28.9 (2.6) weeks, BW 1096 (269) g; twins: GA 28.4 (2.3) weeks, BW 1062 (271) g; triplets: GA 28.5 (2.4) weeks, BW 1049 (259) g). Triplets were significantly more likely to have been conceived following fertility treatments, to have received antenatal steroids, and to be delivered by caesarean section. Respiratory distress syndrome was significantly more common in twins and triplets in spite of the increased exposure to antenatal steroids. Multivariate logistic regression analysis using all significant perinatal covariates showed that triplets were at increased risk of death (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.13 to 2.11), but not of adverse neurological outcome (OR 1.29, 95% CI 0.91 to 1.85) or chronic lung disease (OR 0.69, 95% CI 0.46 to 1.02). CONCLUSION: Despite considerable differences in the incidence of confounding variables between the groups, VLBW triplets are at increased risk of death compared with twins and singletons. In addition, VLBW twins and triplets more often have respiratory distress syndrome but not chronic lung disease or adverse neurological findings.     

Short-term outcome after active perinatal management at 23-25 weeks of gestation. A study from two Swedish perinatal centres. Part 3: neonatal morbidity

Aim: To determine major neonatal morbidity in surviving infants born at 23-25 weeks, and to identify maternal and infant factors associated with major morbidity. Methods: The medical records of 224 infants who were delivered at two tertiary care centres in 1992-1998 were reviewed retrospectively. At these centres, policies of active perinatal and neonatal management were universally applied. Of the 213 liveborn infants, 140 (66%) survived to discharge. Data were analysed by gestational age and considered in three time periods. Logistic regression models were used to identify factors associated with morbidity. Results: Of the survivors, 6% had intraventricular haemorrhage grade ≥3 (severe IVH) or periventricular leukomalacia (PVL), 15% retinopathy of prematurity ≥stage 3 (severe ROP) and 36% bronchopulmonary dysplasia (BPD). On logistic regression analysis, severe IVH or PVL was associated with duration of mechanical ventilation (odds ratio, OR: 1.53 per 1-wk increment in duration; 95% confidence interval, CI: 1.01-2.33). Severe ROP was associated with the presence of a patent ductus arteriosus (PDA) (OR: 3.31; 95% CI: 1.11-9.90) and birth in time period 3 versus time periods 1 and 2 combined (OR: 6.28; 95% CI: 2.10-18.74). BPD was associated with duration of mechanical ventilation (OR: 2.71 per 1-wk increment in duration; 95% CI: 1.76-4.18) and with the presence of any obstetric complication (OR: 2.67; 95% CI: 1.07-6.65). Gestational age and birthweight were not associated with major morbidity. Of all survivors, 81% were discharged home without severe IVH, PVL or severe ROP.

Conclusions: Increased survival as a result of active perinatal and neonatal management was associated with favourable morbidity rates compared with those in recent studies. Among survivors born at 23-25 weeks, neither gestational age nor birthweight was a significant determinant of major morbidity.     

SGA subtypes and mortality risk among singleton births

OBJECTIVES: To determine whether early mortality (first year of life) risks among small for gestational age (SGA) neonates were similar regardless of SGA subtype based on three chronological classifications (term, preterm and post-term). STUDY DESIGN: Retrospective cohort study on all singleton live births in the United States from 1995 to 1999 inclusive. Adjusted risk estimates were computed from logistic regression models using non-SGA infants as the referent. RESULTS: When SGA infants were compared as a homogeneous entity to non-SGA infants, the risks for infant, neonatal and post-neonatal mortality were significantly greater in SGA infants [AOR (adjusted odds ratio)=3.0, 95% CI (confidence interval)=2.9-3.0 for infant mortality; AOR=3.2, 95% CI=3.1-3.2 for neonatal mortality; and AOR=2.6, 95% CI=2.6-2.7 for post-neonatal mortality]. However, heterogeneity existed in terms of mortality risk thresholds across SGA babies. The most remarkable risk magnitude was observed among preterm SGA infants [infant mortality AOR=13.8, 95% CI=13.6-14.1; neonatal death AOR=17.4, 95% CI=17.0-17.7; and post-neonatal death AOR=7.4, 95% CI=7.1-7.6]. The adjusted odds ratio for term and post-term SGA infants were comparable regardless of the period during infancy, and were much less than those observed for preterm SGA infants. CONCLUSIONS: SGA is a heterogeneous disease in terms of prognosis for survival. Preterm SGA infants bear an extremely high risk for mortality during infancy, and counseling of affected parents should reflect this risk divergence.     

Excess mortality and morbidity among small-for-gestational-age premature infants: a population-based study

OBJECTIVE: We examined the effect of intrauterine growth restriction on mortality and morbidity in the Israel cohort of very low birth weight premature infants. METHODS: The study population included 2764 singleton very low birth weight infants without congenital malformations born from 24 to 31 weeks of gestation during 1995 to 1999. Four hundred six (15%) were born small for gestational age (SGA). The effect of SGA on death, bronchopulmonary dysplasia, and retinopathy of prematurity was assessed using multiple logistic regression analysis. RESULTS: After adjustment for perinatal risk factors, SGA infants had a 4.52-fold risk for death (95% CI, 3.24-6.33), a 3.42-fold risk for bronchopulmonary dysplasia (95% CI, 2.29-5.13), and a 2.06-fold risk for grade 3 to 4 retinopathy of prematurity (95% CI, 1.15-3.66). CONCLUSIONS: SGA premature infants had an increased risk for death, and major morbidity among survivors was increased.     

Risk factors for delayed discharge home in very-low-birthweight infants:- a population-based study

AIM: To identify risk factors for delayed discharge home in a population-based cohort of very-low-birthweight (VLBW) infants. METHODS: Demographic, pregnancy, perinatal, and neonatal data were collected in a national population-based database on VLBW infants born from 1995 through 2002. Multivariate analysis determined association with delayed discharge (discharge at a postmenstrual age >42 completed weeks). RESULTS: 882 infants with delayed discharge comprised 9.4% of survivors but accounted for 19.8% of total hospital days utilized until discharge home. Infants with delayed discharge compared to those discharged by term were born at an earlier mean gestational age, at a lower mean birthweight, and had a longer mean hospital stay. Delayed discharge was independently associated with decreasing birthweight (OR 1.25, 95% CI 1.19, 1.31), congenital anomalies (OR 4.80, 95% CI 3.66, 6.28), bronchopulmonary dysplasia (OR 5.88, 95% CI 4.60, 7.57), intraventricular hemorrhage grades 3-4 (OR 1.78, 95% CI 1.34, 2.36), sepsis (OR 1.87, 95% CI 1.54, 2.26), and surgically treated necrotizing enterocolitis (OR 20.20, 95% CI 12.85, 32.03).CONCLUSION: VLBW infants with congenital anomalies or severe complications of preterm birth are at increased risk for delayed discharge home. Early identification of these infants may enable interventions aimed at reducing the detrimental effects of prolonged hospitalization and promoting optimal transition from the hospital to the home environment.     

Variation in childhood asthma among former preterm infants

OBJECTIVES: The role of in utero and perinatal exposures in modifying asthma risk among children born prematurely was assessed.Study design Former preterm children (n=251) were identified from a birth cohort. Examinations, including lung function testing, were performed at ages 8 to 11 years. Perinatal exposures were ascertained from neonatal medical records. RESULTS: Univariate predictors of asthma included male gender, African American ethnicity, maternal asthma, and birth weight. Asthmatics were less likely to have been small for gestational age (SGA) than nonasthmatics (12.4% vs 22.7%, P=.04) and had more neonatal pulmonary disease. After adjusting for maternal asthma and demographic factors, asthma was associated with chronic lung disease of infancy, neonatal mechanical ventilation and corticosteroid use, and a higher childhood body mass index. Children who were septic postbirth and girls who were SGA were less likely to have asthma (OR for sepsis, 0.2; 95% CI, 0.1-0.6; OR for girls who were SGA compared with girls who were not SGA, 0.05; CI, 0.01-0.34). CONCLUSIONS: Among premature children, female SGA status and neonatal sepsis appear protective relative to the development of childhood asthma. Differential susceptibility to asthma among preterm children may relate to exposures that operate in the in utero and early postnatal environment to accelerate lung development, alter innate immunity, or both.     

Respiratory distress syndrome in infants with impaired intrauterine growth

The recently introduced intrauterine growth curve, based on ultrasonically estimated foetal weights, was retrospectively applied to an inborn population of 883 infants bom before 33 gestational weeks at the University Hospital of Lund, during 1985–94. The estimation of birthweight deviation resulted in 630 (71.3%) infants with a birthweight appropriate for gestational age (AGA), 244 (27.6%) infants with a birthweight small for gestational age (SGA) and 9(1.1%) infants with a birthweight large for gestational age. Birthweight deviation was associated with an increased mortality [odds ratio (OR) adjusted for gestational age 1.29 per SD (12%) change in birthweight for gestational age, 95% CI: 1.10–1.50; p = 0.002]. At gestational age 25–28 weeks, SGA-infants had an increased incidence of respiratory distress syndrome (RDS) as compared to AGA-infants (OR adjusted for gestational age: 1.98,95% CI: 1.12–3.52; p = 0.019). At gestational age 29–32 weeks, SGA-infants had a lower incidence of RDS as compared to AGA-infants (OR adjusted for gestational age: OR 0.52,95% CI: 0.34–0.80; p = 0.003). After adjustment for confounding variables, infants born at gestational age 25–28 weeks from mothers with pre-eclampsia, appeared to be a high-risk group for RDS, whereas at the age of 29–32 gestational weeks, negative birthweight deviation had a protective effect against RDS. Antenatal corticosteroid administration appeared to have a less beneficial effect on mortality, RDS and cerebral haemorrhage in infants born SGA vs in those born AGA.     

Impact of prematurity on admissions to the neonatal nursery of a rural South African district hospital.

The objectives of this study were to determine causes of admission to a district hospital neonatal nursery; to describe outcomes; and to determine risk factors for these outcomes. The study was based at the neonatal nursery of Hlabisa hospital, KwaZulu/Natal; 149 consecutive admissions to the nursery between May and November 1995 were audited. The main outcome measures were diagnosis, gestational age, birthweight, critical event during admission (sepsis, severe vomiting, diarrhoea, jaundice, fits, apnoea), and outcome (discharged alive, death, discharged with deficit). Most admitted neonates (73; 54 per cent) were aged less than 37 weeks at birth, and 123 (84 per cent) weighed less than 2.5 kg. Prematurity and low birthweight accounted for 114 (81 per cent) admissions. In all, 58 (39 per cent) neonates experienced a total of 72 critical events, the most frequent being sepsis (39; 54 per cent). Although most (114; 77 per cent) were discharged well, 20 (15 per cent) died and three (3 per cent) were discharged with a significant deficit. Sepsis and apnoea were most frequent among the lightest and most immature babies, while fits were more frequent among heavier, mature babies. In a multivariate model, experiencing any critical event (odds ratio [OR] 15.6; 95 per cent CI 3.0-82.6, p = 0.001) was the only significant independent risk factor for mortality, although birthweight (p = 0.068) and gestational age (26-30 vs. > or = 37 weeks; OR 5.6, 95 per cent confidence internal [CI] 0.3-95.7, p = 0.23), further contributed to risk of death. We conclude that a substantial proportion (around 27 per cent) of district perinatal mortality occurs in the neonatal nursery. Several simple and effective interventions exist to minimize neonatal loss in district hospitals in South Africa.     

Outcome of extremely low birth weight survivors at school age: the influence of perinatal parameters on neurodevelopment

Extremely low birth weight (ELBW) is associated with impaired neurodevelopmental outcome in infancy. Information on the long-term cognitive and neurological consequences of ELBW is scarce. We aimed to identify the perinatal and neonatal factors of ELBW infants associated with adverse cognitive and neurological outcome at school age. A regional cohort of 135 ELBW infants born between 1993 and 1998 was prospectively evaluated at 3, 6, 12, and 18 months postmenstrual age and at yearly intervals up to age 10 years. The comprehensive follow-up programme for high-risk infants included neurological examinations and psychometric evaluations. According to the overall results of these tests, children were classified as either being normal or having minor or major impairment. At a mean age of 8.4 (SD: 1.6) years, 43% of children had survived without any impairment. Minor impairment was diagnosed in 39% and major impairment in 18% of assessed children. The proportion of disabled school children rose with decreasing gestational age. The following neonatal complications were significant risk factors for developing major or minor impairment at school age: an increase in head circumference <6 mm per week (OR 4.0, 95% CI: 1.1–14.8), parenteral nutrition ≥6 weeks (OR 2.5, 95% CI: 1.1–6.0), and mechanical ventilation >14 days (OR 2.3, 95% CI: 1.0–5.1). High-grade intraventricular haemorrhage (IVH) and/or PVL (OR 13.3, 95% CI: 4.0–44.9), neonatal seizures (OR 5.2, 95% CI: 1.2–22.4) and bowel perforation, and/or necrotizing enterocolitis (OR 4.4, 95% CI: 1.1–17.0) were significant risk factors for developing major impairment. In spite of the relatively large proportion of normal children, ELBW remains an important risk factor for neurodevelopmental impairment at school age. Thus, measures to prevent complications such as necrotizing enterocolitis, cerebral haemorrhage, and undernutrition remain important goals for neonatal intensive care.     

MOS HIP: McMaster outcome study of hypertension in pregnancy.

BACKGROUND: The offspring of women with hypertension during pregnancy are at increased risk of low birthweight, preterm birth, diseases of prematurity and death. The risk of developing these outcomes among women with either preeclampsia or chronic hypertension, relative to those with gestational hypertension, is not known. STUDY DESIGN: Prospective cohort study. PARTICIPANTS: A total of 1948 singleton women seen at a large tertiary care obstetrical center, whose blood pressure was greater than 140/90 mm Hg during pregnancy. The four types of hypertension were strictly defined: 864 women (44.4%) had gestational hypertension, 459 (23.6%) isolated chronic hypertension, 501 (25.7%) isolated preeclampsia, and 124 (6.4%) chronic hypertension with superimposed preeclampsia. OUTCOME MEASURES: The primary outcome of the study was a composite of the diseases of prematurity, need for assisted ventilation for greater than 1 day, or perinatal death. The secondary outcomes were each of those included in the primary endpoint, as well as admission to the neonatal ICU, small for gestational age (SGA) birthweight and preterm birth. We controlled for the effects of other maternal risk factors, such as age, parity, history of preterm delivery, cigarette smoking, pre-pregnancy weight, diabetes mellitus (DM), renal dysfunction, and current use of an antihypertensive agent or prednisone. RESULTS: For the primary composite outcome, compared to the offspring of women with gestational hypertension, the adjusted odds ratio was 1.9 (95% confidence interval 1.2 to 3.0) in the preeclamptic group and 2.0 (95% confidence interval 1.0 to 4.0) for those with chronic hypertension plus superimposed preeclampsia. Those with preeclampsia were at increased risk for small for gestational age birthweight (odds ratio 2.2, 95% confidence interval 1.5 to 3.1), as were the offspring of mothers who had chronic hypertension with superimposed preeclampsia (odds ratio 2.1, 95% confidence interval 1.2 to 3.8). Similarly, the rate of preterm birth before 32 weeks was highest among the infants of both preeclamptic mothers (28.5%; odds ratio 4.7, 95% confidence interval 2.9 to 7.6) and those with chronic hypertension and preeclampsia (30.5%; odds ratio 3.5, 95% confidence interval 1.8 to 6.7). The perinatal mortality rate was highest in the group of women with chronic hypertension plus preeclampsia (9.2%; odds ratio 3.2, 95% confidence interval 1.2 to 9.1). Other significant risk factors for the primary composite outcome included previous preterm delivery (odds ratio 2.7, 95% confidence interval 1.4 to 5.2), smoking (odds ratio 1.8, 95% confidence interval 1.1 to 3.0) and use of an antihypertensive agent during pregnancy (odds ratio 1.8, 95% confidence interval 1.2 to 2.7). Prednisone use was strongly associated with risk for perinatal death (odds ratio 4.9, 95% confidence interval 1.4 to 17.1). CONCLUSIONS: Relative to women with isolated gestational hypertension, those who develop preeclampsia, either with or without underlying chronic hypertension, experience worse perinatal outcomes. A history of previous preterm delivery and maternal smoking increase the rate preterm birth and major perinatal disease. Antihypertensive and prednisone therapy may be important risk factors for adverse perinatal events, but further research is needed to confirm these findings.     

Effect of birth order on neonatal morbidity and mortality among very low birthweight twins: a population based study

OBJECTIVE: To study the effect of birth order on the risk for respiratory distress syndrome (RDS), chronic lung disease (CLD), adverse neurological findings, and death in very low birthweight (VLBW; < 1500 g) twins. METHODS: A population based study of VLBW infants from the Israel National VLBW Infant Database. The sample included all complete sets of VLBW twin pairs admitted to all 28 neonatal intensive care units between 1995 and 1999. Outcome variables were compared by birth order and stratified by mode of delivery and gestational age, using General Estimating Equation models, with results expressed as odds ratio (OR) with 95% confidence interval (CI). RESULTS: Second twins were at increased risk for RDS (OR 1.51, 95% CI 1.29 to 1.76), CLD (OR 1.36, 95% CI 1.11 to 1.66), and death (OR 1.24, 95% CI 1.02 to 1.51) but not for adverse neurological findings (OR 1.20, 95% CI 0.91 to 1.60). Mode of delivery did not significantly influence outcome. The odds ratio for RDS in the second twin was inversely related to gestational age, and the increased risk for RDS and CLD was found in both vaginal and caesarean deliveries. CONCLUSIONS: VLBW second twins are at increased risk for acute and chronic lung disease and neonatal mortality, irrespective of mode of delivery.     

Occurrence and severity of bronchopulmonary dysplasia and respiratory distress syndrome after a preterm birth

BACKGROUND:

Despite notable advances in neonatal care, bronchopulmonary dysplasia (BPD) remains an important complication of preterm birth, frequently resulting in prolonged hospital stay and long-term morbidity.

METHODS:

A historical cohort study of all preterm infants (gestational age younger than 37 weeks) admitted to the Montreal Children’s Hospital (Montreal, Quebec) between January 1, 1980, and December 31, 1992, was conducted. Information collected included demographic data, maternal and perinatal history, and main neonatal outcomes. Independent risk factors associated with BPD were identified by univariate analysis using one-way ANOVA, t tests or Mantel-Haenszel χ² testing. Severity of disease was studied using an ordinal multinomial logistic regression model.

RESULTS:

In total, 1192 preterm infants were admitted, of whom 551 developed respiratory distress syndrome and 322 developed BPD. For each additional week of prematurity, the risk of developing BPD increased by 54% (adjusted OR 1.54/week [95% CI 1.45 to 1.64]). For each point subtracted on the 1 min Apgar score, the risk of developing BPD was increased by 16% (OR 1.16 [95% CI 1.1 to 1.3]). BPD was also associated with the presence of patent ductus arteriosus (OR 3.5 [95% CI 2.1 to 6.0]), pneumothorax in the first 48 h (OR 9.4 [95% CI 3.6 to 24.8]) or neonatal pneumonia/sepsis in the neonatal period (OR 1.9 [95% CI 1.1 to 3.2]). Severity of BPD was associated with gestational age, 1 min Apgar score, very low birth weight and the presence of neonatal pneumonia/sepsis.

CONCLUSION:

Factors associated with BPD following a preterm birth were the degree of prematurity, birth weight, Apgar score at 1 min, and the presence of patent ductus arteriosus, pneumothorax or neonatal pneumonia/sepsis.     

胎龄≤32周早产儿低血糖的危险因素分析

目的 探讨胎龄≤32周早产儿出生后发生低血糖的危险因素。方法 回顾性纳入2017年1月至2020年6月入住新生儿重症监护病房的86例胎龄≤32周低血糖早产儿作为低血糖组,随机选取同期住院监测血糖正常的早产儿172例为对照组。采用单因素分析与多因素logistic回归分析筛选早产儿低血糖的危险因素。结果 研究期间早产儿共计515例,其中低血糖86例（16.7%）。低血糖组小于胎龄儿（SGA）、剖宫产出生、孕母高血压、产前使用激素的比例均高于对照组（P < 0.05）,而出生体重及血糖检测前已静脉使用葡萄糖的比例均低于对照组（P < 0.05）。SGA（OR=4.311,95% CI：1.285~14.462）、孕母高血压（OR=2.469,95% CI：1.310~4.652）和产前使用激素（OR=6.337,95% CI：1.430~28.095）为早产儿低血糖的危险因素（P < 0.05）,静脉使用葡萄糖（OR=0.318,95% CI：0.171~0.591）为早产儿低血糖的保护因素（P < 0.05）。结论 SGA、孕母高血压和产前使用激素可增加胎龄≤32周早产儿早期发生低血糖的风险;对胎龄≤32周早产儿,建议生后尽早静脉使用葡萄糖,以减少低血糖的发生。     

A case–control study to examine the association between breastfeeding during late pregnancy and risk of a small‐for‐gestational‐age birth in Lima,Peru

Excessive demands on maternal nutritional status may be a risk factor for poor birth outcomes. This study examined the association between breastfeeding during late pregnancy (≥28 weeks) and the risk of having a small‐for‐gestational‐age (SGA) newborn, using a matched case–control design (78 SGA cases: birthweight <10th percentile for gestational age; 150 non‐SGA controls: 50th percentile <birthweight <90th percentile for gestational age). Between March 2006 and April 2007, project midwives visited daily three government hospitals in Lima, Peru and identified cases and matched controls based on hospital, gestational age, and inter‐gestational period. Mothers were interviewed and clinical chart extractions were completed. Factors associated with risk of SGA were assessed by their adjusted odds ratios (aOR) from conditional logistic regression. Exposure to an overlap of breastfeeding during late pregnancy was not associated with an increased risk of having a SGA newborn [aOR = 0.58, 95% confidence interval (CI): 0.10–3.30]. However, increased risk was associated with having a previous low‐birthweight birth (aOR = 6.53; 95% CI: 1.43–29.70) and a low intake of animal source foods (<25th percentile; aOR = 2.26; 95% CI: 1.01–5.04), and tended to be associated with being short (<150 cm; aOR = 2.05; 95% CI: 0.92–4.54). This study found no evidence to support the hypothesis that breastfeeding during late pregnancy increases the risk for SGA; however, studies with greater statistical power are needed to definitively examine this possible association and clarify whether there are other risks to the new baby, the toddler and the pregnant woman.     

Motor skills in adolescents with low birth weight

BACKGROUND: Minor motor problems have been reported in low birthweight children, but few studies have assessed motor skills in adolescents. OBJECTIVE: To examine the prevalence of motor problems in adolescents with low birth weight. METHOD: Fifty four very low birthweight (VLBW: birth weight < or = 1500 g), 59 term small for gestational age (SGA: birth weight < 10th centile), and 83 control (birth weight > or = 10th centile at term) children were assessed with the Movement assessment battery for children (Movement ABC) at the age of 14 in a population based study. RESULTS: One in four VLBW children (odds ratio (OR) 9.3, 95% confidence interval (CI) 2.5 to 34.5) and one in six SGA children (OR 4.7, 95%CI 1.2 to 18.4) had motor problems compared with controls (3.7%). There were no sex differences in motor problems in the VLBW group, and the increased risk was consistent across the continuum of the Movement ABC. For SGA children, the increased risk of motor problems was particularly in manual dexterity in boys. CONCLUSION: VLBW and SGA adolescents have increased risk of motor problems compared with control children.     

Prenatal predictors of mortality in very preterm infants cared for in the Australian and New Zealand Neonatal Network

AIM: To identify antenatal and perinatal risk factors for in-hospital mortality of babies born within the Australian and New Zealand Neonatal Network (ANZNN). METHODS: Data were collected prospectively as part of the ongoing audit of high-risk infants (birth weight <1500 g or gestation <32 weeks) admitted to all level III neonatal units in Australia and New Zealand. Antenatal and intrapartum factors to 1 min of age were examined in 11 498 infants with gestational age >24 weeks. Risk and protective factors for mortality were derived from logistic regression models fitted to 1998-9 data and validated on 2000-1 data. RESULTS: For the whole cohort of infants born between 1998 and 2001, prematurity was the dominant risk factor, infants born at 25 weeks having 32 times greater odds of death than infants born at 31 weeks. Low birth weight for gestational age also had a dose-response effect: the more growth restricted the infant the greater the risk of mortality; infants below the 3rd centile had eight times greater odds of death than those between the 25th and 75th centiles. Male sex was also a significant risk factor (odds ratio (OR) 1.55, 95% confidence interval (CI) 1.31 to 1.82). Maternal hypertension in pregnancy was protective (OR 0.46, 95% CI 0.36 to 0.50). The predictive model for mortality had an area under the receiver operating characteristic curve of 0.82. CONCLUSIONS: Risk of mortality can be predicted with good accuracy with factors up to the 1 min Apgar score. By using gestation rather than birth weight as the main indicator of maturity, these data confirm that weight for gestational age is an independent risk factor for mortality.     

Sex differences in outcomes of very low birthweight infants: the newborn male disadvantage

OBJECTIVE: To determine the differences in short term outcome of very low birthweight infants attributable to sex. METHODS: Boys and girls weighing 501-1500 g admitted to the 12 centres of the National Institute of Child Health and Human Development Neonatal Research Network were compared. Maternal information and perinatal data were collected from hospital records. Infant outcome was recorded at discharge, at 120 days of age if the infant was still in hospital, or at death. Best obstetric estimate based on the last menstrual period, standard obstetric factors, and ultrasound were used to assign gestational age in completed weeks. Data were collected on a cohort that included 3356 boys and 3382 girls, representing all inborn births from 1 May 1991 to 31 December 1993. RESULTS: Mortality for boys was 22% and that for girls 15%. The prenatal and perinatal data indicate few differences between the sex groups, except that boys were less likely to have been exposed to antenatal steroids (odds ratio (OR) = 0.80) and were less stable after birth, as reflected in a higher percentage with lower Apgar scores at one and five minutes and the need for physical and pharmacological assistance. In particular, boys were more likely to have been intubated (OR = 1.16) and to have received resuscitation medication (OR = 1.40). Boys had a higher risk (OR > 1.00) for most adverse neonatal outcomes. Although pulmonary morbidity predominated, intracranial haemorrhage and urinary tract infection were also more common. CONCLUSIONS: Relative differences in short term morbidity and mortality persist between the sexes.     

Maternal nutritional status mediates the association between maternal age and birth outcomes

Young maternal age during pregnancy is linked with adverse birth outcomes. This study examined the role of maternal nutritional status in the association between maternal age and small for gestational age (SGA) delivery and birth length. We used data from a birth cohort study in Ethiopia, involving women who were 15–24 years of age and their newborns. A mediation analysis was fitted in a sample of 1,422 mother infant dyads for whom data on birth length were available, and 777 dyads for whom gestational age and birth weight was measured. We used commands, medeff for the mediation analysis and medsens for sensitivity analysis in STATA 14. Maternal nutritional status, measured by mid‐upper arm circumference, mediated 21% of the association between maternal age and birth length and 14% of the association with SGA delivery. The average direct effect (ADE) of maternal age on birth length was (β = 0.45, 95% CI [0.17, 0.99]) and the average causal mediated effect (ACME) was (β = 0.12, 95% CI [0.02, 0.15]). We also found an ADE (β = 0.31, 95% CI [0.09, 0.47]) and an ACME of (β = 0.05, 95% CI [0.003, 0.205]) of maternal age on SGA delivery. The sensitivity analysis suggests an unmeasured confounder with a positive correlation of 0.15 and 0.20 between the mediator and the outcome could explain the observed ACME for birth length and SGA, respectively. We cannot make strong causal assertions as the findings suggest the mediator partly explained the total effect of maternal age on both outcomes.     

Associations between prepregnancy body mass index,gestational weight gain and weight catch-up in small-for-gestational-age children

Inadequate gestational weight gain (GWG) was related with a higher incidence of small-for-gestational-age (SGA) births than appropriate GWG; however, the long-term association of maternal GWG with weight catch-up growth in SGA children remains unknown. The objective of this study is to evaluate the associations between prepregnancy body mass index (pBMI), GWG and weight catch-up patterns in SGA children. Data were from the Collaborative Perinatal Project, an American multicentre prospective cohort study. A total of 56,990 gravidas were recruited at the first prenatal visit, and children were followed up until school age. Maternal pBMI, GWG and physical growth of the offspring at birth, 4 months, 1 year, 4 years and 7 years old were recorded. The latent class analysis was employed to form weight catch-up growth patterns (appropriate, excessive, slow, regression and no catch-up patterns) in SGA children. SGA children who developed the ‘appropriate catch-up growth’ pattern and whose mothers had appropriate pBMI and GWG were chosen as the reference. Associations between GWG for different pBMI and weight catch-up patterns were analysed by multivariate logistic regression models. A total of 1619 infants (9.45%) were born term SGA. After adjusting for relevant confounders, compared with SGA children whose mothers had appropriate pBMI and GWG, SGA children with maternal prepregnancy underweight (for inadequate GWG, GWG below recommendations, adjusted OR: 2.88, 95% CI: 1.13–7.31; for appropriate/excessive GWG, adjusted OR: 3.07, 95% CI: 1.74–5.42) or with prepregnancy normal weight but inadequate GWG (adjusted OR: 2.14, 95% CI: 1.36–3.38) were at a higher risk of having the ‘no catch-up growth’ pattern. We suggest that SGA children with maternal prepregnancy underweight or inadequate GWG tend to have a poor weight catch-up growth at least until school age.     

Outcome following pulmonary haemorrhage in very low birthweight neonates treated with surfactant.

AIM: To determine if pulmonary haemorrhage after surfactant treatment increases short and long term morbidity and mortality in neonates weighing <1500 g at birth. METHODS: Neonates weighing <1500 g at birth who developed pulmonary haemorrhage after surfactant treatment were identified from a database. Based on the change in FIO2, pulmonary haemorrhage was classified as mild, moderate, or severe. Controls were matched for birthweight, gestational age, Apgar scores and hospital. Chronic lung disease (CLD) was defined as the need for supplemental oxygen at 36 weeks of corrected gestational age. RESULTS: From January 1990 to May 1994, 94 of 787 (11.9%) neonates treated with surfactant developed pulmonary haemorrhage. Ten were excluded because of incomplete data or lack of controls. Eighty four were included for further analysis; two acceptable matches were found in 75, while only one match was possible in nine. For the pulmonary haemorrhage group, the mean (SD) birthweight was 917 (238) g, gestational age 27 (1.9) weeks. Pulmonary haemorrhage was severe in 39 (46%), moderate in 22 (26%), and mild in 23 (27%). Moderate and severe pulmonary haemorrhage were associated with chronic lung disease or death, OR 4.4 (confidence interval 1.3-15.7) and OR 7.8 (CI 2.6-28), respectively, while mild pulmonary haemorrhage was not, OR 1.8 (CI 0.55-5.8). pulmonary haemorrhage was associated with major intraventricular haemorrhage (IVH), OR 3.1 (CI 1.5-6.4), but not with minor IVH, OR 1.3 (CI 0.6-2. 6). In the survivors who could be assessed at >/=2 years, the differences in neurodevelopmental outcome among the two groups were not significant. CONCLUSIONS: In neonates treated with surfactant moderate and severe pulmonary haemorrhage is associated with an increased risk of death and short term morbidity. Pulmonary haemorrhage does not seem to be associated with increased long term morbidity.