The Swedish national prospective study on extremely low birthweight (ELBW) infants. Incidence, mortality, morbidity and survival in relation to level of care

Short-term outcome predictors in infants born at 23-24 gestational weeks

AIM

Outcome is uncertain in infants born at 23-24 gestational weeks. The aim of the present study was to identify possible early predictors of outcome in these infants.

MATERIALS AND METHODS

Data from the Swedish medical birth register (MBR) for live-born infants with gestational ages (GAs) 23 and 24 weeks, born during the time-period 2000-2002, were analysed in relation to short-term outcomes, that is survival and survival without severe brain damage (intraventricular haemorrhage [IVH] grades 3 and 4 and/or periventricular leukomalacia [PVL]).

RESULTS

In 57 infants born at 23 gestational weeks, survival was associated with birthweight (BW) (p = 0.018) and 5-min Apgar score (p = 0.020) on univariate analyses. In 99 infants born at 24 weeks of gestation, survival without severe brain damage correlated with BW (p = 0.039), birth type (singleton/multiple) (p = 0.017) and Apgar score at 1, 5 and 10 min (p = 0.028, 0.014 and 0.030, respectively). The best model for predicting survival without severe brain damage in infants born at 24 gestational weeks was based on 5-min Apgar score and birth type. The small number of live-born infants at 23 weeks of gestation did not allow for multiple logistic regression analyses.

CONCLUSION

The 5-min Apgar score is associated with short-term outcome in live-born infants at 23-24 gestational weeks. The association is stronger for infants born at 24 weeks of gestation.

Selective use of sonographic cervical length measurement for predicting imminent preterm delivery in women with preterm labor and intact membranes

OBJECTIVES

To determine, in a population of women with preterm labor and intact membranes, whether ultrasound cervical length measurement performed only in patients selected according to the Bishop score predicts imminent preterm delivery better than does systematic cervical length measurement in the entire population.

METHODS

The Bishop score and sonographic cervical length were recorded prospectively in women with preterm labor between 24 and 34 completed weeks' gestation. Outcome measures were preterm delivery within 48 h and within 7 days. Predictive values were calculated for each marker separately and then in combination.

RESULTS

Of the study population of 395 women, 17 (4.3%) and 32 (8.1%) delivered within 48 h and within 7 days, respectively, following inclusion. For delivery within 7 days, areas under the Bishop score (0.848) and sonographic cervical length (0.813) receiver-operating characteristics curves did not differ significantly. For the selective use of sonographic cervical length measurement in patients selected according to the Bishop score, the test was considered positive if the Bishop score was >or= 8, or 4-7 with cervical length <or= 30 mm. This test was as sensitive (94%) but more specific (60% vs. 42%, P < 0.001) for predicting preterm birth within 7 days than was sonographic cervical length with a 30-mm cut-off value in the entire population. Results were similar for delivery within 48 h.

CONCLUSION

For predicting imminent preterm delivery in women with preterm labor, measuring sonographic cervical length only in patients with a Bishop score between 4 and 7, compared with a strategy of systematic measurement in the entire population, reduces by 30% the number of false positives and might thus decrease unnecessary therapeutic intervention.

Risk factors for not delivering in a level III unit before 32 weeks of gestation: results from a population-based study in Paris and surrounding districts in 2003

Delivery of very preterm babies in maternity units with on-site neonatal intensive care (level III units) is associated with lower mortality and morbidity. This analysis explores risk factors for not delivering in a level III unit, using data from a population-based study of very preterm births in Paris and surrounding districts in 2003. The sample for analysis included resident women with a fetus alive at the onset of labour between 24 and 31 weeks of gestation (n = 641). Characteristics of women delivering in and those not in level III units were compared using logistic regression. Further analysis was carried out for the subgroup of women not already scheduled to deliver in a level III unit. Twenty-nine per cent of women did not deliver in level III units; in the subgroup scheduled to deliver in level I or II units, 43% were not transferred. Women were less likely to deliver in a level III unit if they had a singleton pregnancy, a gestation of <26 weeks or at 31 weeks, experienced antenatal haemorrhaging, lived in socially deprived neighbourhoods or at a greater distance from the nearest level III. Women scheduled to deliver in a maternity unit with a special care nursery were also less likely to deliver in a level III unit. In contrast, preterm rupture of membranes and fetal growth restriction increased the likelihood of a level III delivery. These results underline the importance of controlling for clinical characteristics when analysing perinatal outcome by place of delivery and show how socioeconomic factors, known to impact on the risk of having a preterm birth, can also affect access to appropriate care.

An overview of mortality and sequelae of preterm birth from infancy to adulthood

Survival rates have greatly improved in recent years for infants of borderline viability; however, these infants remain at risk of developing a wide array of complications, not only in the neonatal unit, but also in the long term. Morbidity is inversely related to gestational age; however, there is no gestational age, including term, that is wholly exempt. Neurodevelopmental disabilities and recurrent health problems take a toll in early childhood. Subsequently hidden disabilities such as school difficulties and behavioural problems become apparent and persist into adolescence. Reassuringly, however, most children born very preterm adjust remarkably well during their transition into adulthood. Because mortality rates have fallen, the focus for perinatal interventions is to develop strategies to reduce long-term morbidity, especially the prevention of brain injury and abnormal brain development. In addition, follow-up to middle age and beyond is warranted to identify the risks, especially for cardiovascular and metabolic disorders that are likely to be experienced by preterm survivors.

[Current management of the HELLP syndrome]

The HELLP syndrome as part of the microangiopathic syndromes requires special attention in terms of a rapid and accurate diagnostic and differential diagnostic workup because of its possibly rapid clinical deterioration. It is defined by the classical triad of hemolysis,elevated liver enzymes and low platelet counts which may lead to prognostically relevant problems in differentiating it from thrombotic-thrombocytopenic purpura and hemolytic-uremic syndrome and other pregnancy-related and unrelated liver diseases, i.e. mainly clinical and laboratory similarities to other liver diseases such as acute fatty liver or intrahepatic cholestasis in pregnancy or pregnancy-unrelated settings like viral hepatitides. The management in the different phases of pregnancy is described in detail. Therapeutic options to prolong pregnancy are discussed as are the possibilities of prophylaxis in subsequent pregnancies and aspects of the followup.

Characteristics of neonatal units that care for very preterm infants in Europe: results from the MOSAIC study

OBJECTIVES

We sought to compare guidelines for level III units in 10 European regions and analyze the characteristics of neonatal units that care for very preterm infants.

METHODS

The MOSAIC (Models of Organising Access to Intensive Care for Very Preterm Births) project combined a prospective cohort study on all births between 22 and 31 completed weeks of gestation in 10 European regions and a survey of neonatal unit characteristics. Units that admitted > or = 5 infants at < 32 weeks of gestation were included in the analysis (N = 111). Place of hospitalization of infants who were admitted to neonatal care was analyzed by using the cohort data (N = 4947). National or regional guidelines for level III units were reviewed.

RESULTS

Six of 9 guidelines for level III units included minimum size criteria, based on number of intensive care beds (6 guidelines), neonatal admissions (2), ventilated patients (1), obstetric intensive care beds (1), and deliveries (2). The characteristics of level III units varied, and many were small or unspecialized by recommended criteria: 36% had fewer than 50 very preterm annual admissions, 22% ventilated fewer than 50 infants annually, and 28% had fewer than 6 intensive care beds. Level II units were less specialized, but some provided mechanical ventilation (57%) or high-frequency ventilation (20%) or had neonatal surgery facilities (17%). Sixty-nine percent of level III and 36% of level I or II units had continuous medical coverage by a qualified pediatrician. Twenty-two percent of infants who were < 28 weeks of gestation were treated in units that admitted fewer than 50 very preterm infants annually (range: 2%-54% across the study regions).

CONCLUSIONS

No consensus exists in Europe about size or other criteria for NICUs. A better understanding of the characteristics associated with high-quality neonatal care is needed, given the high proportion of very preterm infants who are cared for in units that are considered small or less specialized by many recommendations.

Mental health and social competencies of 10- to 12-year-old children born at 23 to 25 weeks of gestation in the 1990s: a Swedish national prospective follow-up study

OBJECTIVE

We investigated a national cohort of extremely immature children with respect to behavioral and emotional problems and social competencies, from the perspectives of parents, teachers, and children themselves.

METHODS

We examined 11-year-old children who were born before 26 completed weeks of gestation in Sweden between 1990 and 1992. All had been evaluated at a corrected age of 36 months. At 11 years of age, 86 of 89 survivors were studied and compared with an equal number of control subjects, matched with respect to age and gender. Behavioral and emotional problems, social competencies, and adaptive functioning at school were evaluated with standardized, well-validated instruments, including parent and teacher report questionnaires and a child self-report, administered by mail.

RESULTS

Compared with control subjects, parents of extremely immature children reported significantly more problems with internalizing behaviors (anxiety/depression, withdrawn, and somatic problems) and attention, thought, and social problems. Teachers reported a similar pattern. Reports from children showed a trend toward increased depression symptoms compared with control subjects. Multivariate analysis of covariance of parent-reported behavioral problems revealed no interactions, but significant main effects emerged for group status (extremely immature versus control), family function, social risk, and presence of a chronic medical condition, with all effect sizes being medium and accounting for 8% to 12% of the variance. Multivariate analysis of covariance of teacher-reported behavioral problems showed significant effects for group status and gender but not for the covariates mentioned above. According to the teachers' ratings, extremely immature children were less well adjusted to the school environment than were control subjects. However, a majority of extremely immature children (85%) were functioning in mainstream schools without major adjustment problems.

CONCLUSIONS

Despite favorable outcomes for many children born at the limit of viability, these children are at risk for mental health problems, with poorer school results.

A population based 10-year study of neonatal air transport in North Norway

AIM

This study audits the activity of the neonatal air transport team in Norway's two northernmost counties.

METHODS

Data on all air transports to or from the regional Neonatal Intensive Care (NICU) Unit within a 10-year period were collected.

RESULTS

Two hundred and thirty-eight acute transports were conducted during the study period; 169 referrals to the NICU and 69 transfers to national surgical and cardiac centres. Only 13 very low birth weight infants were transported; the in utero transport rate was 95% for this patient population. The adjusted risk of death and/or intracranial haemorrhage for outborn very low birth weight infants was five-fold increased compared to those not transported postnatally. Babies with congenital heart disease comprised the one-fourth of all transports. The long-term mortality was 14% for the whole study population, and 29% for infants with congenital heart disease. Only seven deaths (3.2%) were defined as being transport-related; death during or within 24 h after transport. However, preventable complications like temperature instability, hypoglycaemia and hypo-/hypercapnia occurred in 10-20% of all transports.

CONCLUSION

The transport related mortality was low in this study, however very low birth weight infants and infants with major congenital heart disease showed a relatively poor outcome.

The choice of a tocolytic for the treatment of preterm labor: a critical evaluation of nifedipine versus atosiban

Preterm birth is the major cause of neonatal mortality and morbidity in the developed world. The perfect tocolytic that is uniformly effective with complete fetomaternal safety does not exist. Tocolytic agents differ in cost, utero-specificity, safety, efficacy and whether they are licensed for use. The main three agents that are used worldwide are beta-agonists, Ca(2+) channel blockers and vasopressin/oxytocin receptor antagonists. beta-Agonists are gradually being phased out of use and are being replaced by either nifedipine or atosiban. The evidence base for atosiban is strong but the evidence is of poor quality for nifedipine. The balance of evidence indicates that atosiban is as effective as nifedipine and more effective than beta-agonists and is significantly safer than both. Atosiban was developed specifically to treat preterm labor, so the cost is higher than nifedipine or ritodrine. However, the cost of a course of atosiban (approximately 200 pounds) should not only be considered in comparison with other tocolytic agents but to other medical budgets (e.g., oncology, fertility, cardiology and psychiatry) and to the huge healthcare costs associated with the morbidity and mortality caused by preterm birth. Atosiban is a new advance in the management of spontaneous preterm labor.

Emerging drug therapies for preventing spontaneous preterm labor and preterm birth

Preterm birth (PTB) is the main cause of neonatal mortality and morbidity in the developed world. Historically, the approach for the prevention of PTB has been reactive rather than proactive. With the introduction of new screening tests and a greater emphasis on prevention rather than treatment, a number of new approaches have been introduced that show promise. Progesterone, which is responsible for myometrial quiescence in pregnancy and is used in women with a previous history of PTB, is associated with a significant reduction in the incidence of PTB and low birth weight. Infection is an important cause of PTB in < or = 40% of women. The appropriate antibiotics administered early in pregnancy to women with abnormal genital tract flora have been associated with a 40-60% reduction in the incidence of PTB. Although there has been debate regarding the benefits of nutritional supplementation for the prevention of many complications of pregnancy, recent evidence suggests that fish oil supplementation can be shown to reduce the incidence of PTB in women at risk of PTB. Although these three proactive, preventative approaches show promise, further research is needed to establish the best agent, the optimum gestational age at commencement and cessation, the ideal candidate patient to achieve a response and the long-term feto-maternal benefits and/or side effects.

Apgar score predicts short-term outcome in infants born at 25 gestational weeks

AIM

To identify early predictors of outcome in infants born at 25 gestational weeks.

MATERIAL AND METHODS

Data from a regional perinatal database (time-period 1995-2001, total n = 108 000 births) were used. Apgar scores were available in 92 preterm infants, born at 25 + 0 to 25 + 6 gestational weeks, and analyzed in relation to short-term outcome (180-day survival with, or without, severe brain damage defined as intraventricular hemorrhage grade 3-4 or cystic periventricular leukomalacia). Based on multiple logistic regression analyses we constructed graphs of the estimated chance of survival.

RESULTS

Apgar scores at 1, 5 and 10 min correlated with survival without severe brain damage (p = 0.02, 0.006 and 0.006, respectively). Survival without severe brain damage was higher in singleton than in multiple births (p = 0.03); there was no association with infant gender or mode of delivery. The strongest model for prediction of survival without severe brain damage was based on 5-min Apgar score and the Clinical Risk Index for Babies (CRIB), (p < 0.001).

CONCLUSION

Apgar score predicts short-term outcome in extremely preterm infants at 25 gestational weeks. The precision for prediction of outcome increases when Apgar score is combined with CRIB.

Use of tocolytics: what is the benefit of gaining even more time?

Today's dogma states that tocolytics can be used to prolong pregnancy for just 48 hours, allowing corticosteroids to be administered and transportation of the mother to a tertiary care centre. Surveys have shown that up to 30% of practitioners use maintenance tocolysis. Theoretically, maintenance tocolysis should be able to improve neonatal outcome by avoiding preterm birth and allowing delivery in the community maternity hospital or even at home, minimising social difficulties created by long distances between the mother and/or her baby and the rest of the family. This should result in fewer neonatal intensive care unit admissions, less respiratory distress syndrome and fewer long-term neurological sequelae. Such an effect has never been proven, probably because we do not know which women benefit from treatment, which do not require treatment because they are not in labour and which babies would better be born because chorioamnionitis and other insults jeopardize intrauterine development. Most studies on long-term tocolysis have been performed with beta-agonists. No improvement has been shown. On the contrary, a trend towards fetal harm with an increased risk for periventricular leucomalacia exists. Results from studies of one tocolytic should not be generalised; one published study on maintenance therapy with atosiban showed prolonged uterine quiescence and prolonged gestation, but was too small to detect differences in neonatal outcome. In the future, we need larger studies, not only to detect whether long-term tocolysis with newer tocolytics (oral oxytocin antagonists, prostaglandin receptor blockers) results in better neonatal outcome, especially at the lower gestational ages but also to discover methods that allow us to identify those women who will benefit from treatment and those for whom prolongation of pregnancy may cause harm.

Diagnosis of early preterm labour

While preterm contractions occur almost as often extremely preterm as they do closer to term, birth due to spontaneous preterm labour before 27 weeks of gestation is rare, accounting for 0.05-0.7% of all births in different populations. Although the likelihood that uterine contractions before 27 weeks of gestation represent true preterm labour is low, the risk of adverse outcome in such cases is high. A correct diagnosis is important, and a useful diagnostic test should have a high sensitivity. In most reports, only 30-40% of women hospitalised for spontaneous preterm labour experience a preterm birth, suggesting a low positive predictive value of clinical diagnosis based on uterine contractions and vaginal examination. Transvaginal ultrasonographic scanning (TVUSS) of cervical length has shown a high sensitivity for preterm birth, 90-100% for preterm birth before 33-35 weeks, using a liberal cutoff at 30 mm. Assessment of cervicovaginal fetal fibronectin (FFN) levels has shown a sensitivity of about 80%. Adding FFN assessment to TVUSS might contribute insignificantly to the prediction of preterm birth. In a retrospective study of 147 women with spontaneous preterm labour and intact membranes before 27 weeks in our department, 61% of hospitalised women and 77% of women receiving tocolytic infusion therapy delivered before 32 weeks. Among 66 singleton pregnancies delivered before 32 weeks, at admission, 94% either had an effaced cervix or cervix with >/=2 cm dilation (74%), vaginal bleeding (61%) or serum C-reactive protein level >20 mg/l (40%), whereas one of these findings only was present in 18% of women who delivered at later gestations. Among 132 women with symptoms of spontaneous preterm contractions before 27 weeks not admitted for hospital care, only 2 (1.5%) delivered before 32 weeks, not significantly higher than for all other women (0.6%). Although TVUSS may be useful when the diagnosis of spontaneous preterm labour is in doubt, the main predicament in early spontaneous preterm labour may not be to predict preterm birth but to prevent it, since many women appear in advanced labour or with manifest chorioamnionitis.

Growth in 10- to 12-year-old children born at 23 to 25 weeks' gestation in the 1990s: a Swedish national prospective follow-up study

BACKGROUND

Knowledge of long-term growth of extremely preterm infants in relation to gestational age is incomplete, and there are concerns regarding their poor growth in early childhood. As part of a longitudinal study of a national cohort of infants born at <26 weeks' gestation (extremely immature), growth development from birth to the age of 11 years was examined, and correlates of growth attainment were analyzed.

METHODS

Two hundred forty-seven extremely immature children were born alive from April 1990 through March 1992 in the whole of Sweden, and 89 (36%) survived. Growth and neurosensory outcomes of all extremely immature survivors were evaluated at 36 months of age. Eighty-six (97%) extremely immature children were identified and assessed at 11 years of age. In this growth study, 83 extremely immature infants (mean [SD]: birth weight, 772 g [110 g]; gestational age, 24.6 weeks [0.6 weeks]) without severe motor disability were followed up prospectively from birth to 11 years old and compared with a matched group of 83 children born at term. z scores for weight, height, head circumference, and BMI were computed for all children. We also examined gender-specific longitudinal growth measures. Predictors of 11-year growth were studied by multivariate analyses.

RESULTS

Extremely immature children were significantly smaller in all 3 growth parameters than the controls at 11 years. Extremely immature children showed a sharp decline in weight and height z scores up to 3 months' corrected age, followed by catch-up growth in both weight and height up to 11 years. In contrast to weight and height, extremely immature children did not exhibit catch-up growth in head circumference after the first 6 months of life. The mean BMI z scores increased significantly from 1 to 11 years in both groups. The mean BMI change between 1 and 11 years of age was significantly larger in extremely immature than in control participants. Extremely immature girls showed a faster weight increase than extremely immature boys, whereas catch-up growth in height and head circumference was similar in these groups. Multiple-regression analyses revealed that preterm birth and parental height were significant predictors of 11-year height, and group status (prematurity) correlated strongly with head circumference.

CONCLUSIONS

Children born at the limit of viability attain poor growth in early childhood, followed by catch-up growth to age 11 years, but remain smaller than their term-born peers. Strategies that improve early growth might improve the outcome.

Chronic conditions, functional limitations, and special health care needs in 10- to 12-year-old children born at 23 to 25 weeks' gestation in the 1990s: a Swedish national prospective follow-up study

BACKGROUND

Children born extremely immature (gestational age < 26 weeks' gestation) increasingly reach school age. Information on their overall functioning and special health care needs is necessary to plan for their medical and educational services. This study was undertaken to examine neurosensory, medical, and developmental conditions together with functional limitations and special health care needs of extremely immature children compared with control subjects born at term.

METHODS

We studied 11-year-old children born before 26 completed weeks of gestation in all of Sweden from 1990 through 1992. All had been evaluated at 36 months' corrected age. Identification of children with chronic conditions lasting > or = 12 months was based on a questionnaire administered to parents. Neurosensory impairments were identified by reviewing health records. Information regarding other specific medical diagnoses and developmental disabilities was obtained by standard parent and teacher questionnaires.

RESULTS

Of 89 eligible children, 86 (97%) were studied at a mean age of 11 years. An equal number of children born at term served as controls. Logistic-regression analyses adjusting for social risk factors and gender showed that significantly more extremely immature children than controls had chronic conditions, including functional limitations (64% vs 11%, respectively), compensatory dependency needs (59% vs 25%), and services above those routinely required by children (67% vs 22%). Specific diagnoses or disabilities with higher rates in extremely immature children than in controls included neurosensory impairment (15% vs 2%), asthma (20% vs 6%), poor motor skills of > 2 SDs above the mean (26% vs 3%), poor visual perception of > 2 SDs above the mean (21% vs 4%), poor learning skills of > 2 SDs above the mean (27% vs 3%), poor adaptive functioning with T scores of < 40 (42% vs 9%), and poor academic performance with T score < 40 (49% vs 7%).

CONCLUSIONS

Children born extremely immature have significantly greater health problems and special health care needs at 11 years of age. However, few children have severe impairments that curtail major activities of daily living.

Use of epidural analgesia and its relation to caesarean and instrumental deliveries—a population-based study of 94,217 primiparae

OBJECTIVES

To investigate the association between epidural analgesia for labour-pain relief and mode of delivery.

STUDY DESIGN

The Swedish medical birth register covers 99% of all births and contains prospectively collected information from all delivery units in Sweden. The present population-based cohort study includes singleton births among nulliparae during 1998-2000, excluding deliveries with elective caesarean section, giving study population of n=94,217. The frequencies of epidural block in this population were estimated for each delivery unit. The outcomes studied were non-elective caesarean section and instrumental delivery.

RESULTS

There was no clear association between frequency of epidural block and caesarean section and instrumental delivery, respectively. Delivery units with the lowest (20-29%) and the highest (60-64%) relative frequencies of epidural block had the lowest proportion of caesarean section (9.1%). For the other groups the proportion varied between 10.3 and 10.6%. Instrumental deliveries were most common, 18.8%, in delivery units with 50-59% frequency of epidural block use. The lowest incidence (14.1%) was in units using epidurals in 30-39% of cases. In the other groups (20-29, 40-49 and 60-64%) the proportion varied between 15.3 and 15.7%.

CONCLUSIONS

This investigation shows no clear association between epidural use and caesarean section or instrumental delivery, indicating that there is no reason to restrict the epidural rate to improve obstetric outcome.

Late miscarriage and preterm birth after treatment with clindamycin: a randomised consent design study according to Zelen

OBJECTIVE

To screen for bacterial vaginosis (BV) and to investigate the effect of treatment with vaginal clindamycin in order to observe the effect on late miscarriage and delivery prior to 37 completed weeks (primary outcome).

DESIGN

Randomised consent design for clinical trials according to Zelen.

SETTING

Southeast region of Sweden.

POPULATION

A total of 9025 women were screened in early pregnancy.

METHODS

A total of 819 women with a Nugent score of 6 and above were considered to have BV and treated according to Zelen allocation. The incidence of late miscarriage and spontaneous (noniatrogenic) preterm birth was assessed.

MAIN OUTCOME MEASURES

Late miscarriage and spontaneous preterm delivery before 37 weeks.

RESULTS

Therapy with vaginal clindamycin had no significant impact on the incidence of spontaneous preterm delivery prior to 37 completed weeks; OR 0.90, 95% CI 0.40-2.02 (primary outcome variable). However, only 1 of 11 women in the treatment group versus 5 of 12 in the control group delivered prior to 33 completed weeks; OR 0.14, 95% CI 0.02-0.95. Treatment was associated with 32 days longer gestation for the 23 participants who had late miscarriage or spontaneous preterm birth (P= 0.024, Mann-Whitney U test) and significantly fewer infants had a birthweight below 2,500 g (secondary outcome). A follow up of infants born preterm 4 years postnatally indicated that extending gestational age did not increase the number of sequelae.

CONCLUSIONS

Clindamycin vaginal cream therapy was associated with significantly prolonged gestation and reduced cost of neonatal care in women with BV. Early screening for BV and treatment with clindamycin saved approximately 27 euro per woman.

Early variable-flow nasal continuous positive airway pressure in infants < or =1000 grams at birth

OBJECTIVE

To compare the incidence of chronic lung disease (CLD) in extremely low birth weight (ELBW, < or =1000 g) infants before and after the introduction of early, preferential application of nasal continuous airway pressure (NCPAP) utilizing a variable flow delivery system.

STUDY DESIGN

A retrospective cohort study of ELBW infants 2 years prior to (Pre-early NCPAP, n=96) and 2 years following (Early NCPAP, n=75) the initiation of an early NCPAP policy.

RESULTS

There were no significant changes (Pre-early NCPAP vs Early NCPAP) in the incidences of CLD (35 vs 33%, P=0.81) or CLD or death (50 vs 43%, P=0.34). Infants in the Early NCPAP group weaned off mechanical ventilation and supplemental oxygen more rapidly than infants in the Pre-early NCPAP group (hazard ratio (HR) 1.80, P=0.002 and HR 1.69, P=0.01).

CONCLUSION

A policy of early NCPAP has not decreased the incidence of CLD despite a decrease in time to successful tracheal extubation.

Variation in rates of severe retinopathy of prematurity among neonatal intensive care units in the Australian and New Zealand Neonatal Network

AIM

To analyse variations in rates of severe retinopathy of prematurity (ROP) among neonatal intensive care units (NICUs) in the Australian and New Zealand Neonatal Network (ANZNN), adjusting for sampling variability and for case mix.

METHODS

25 NICUs were included in the study of 2105 infants born at less than 29 weeks in 1998 and 1999, who survived to 36 weeks post-menstrual age and were examined for ROP. The observed NICU rates of severe ROP were adjusted for case mix using logistic regression on gestation, weight for gestational age and sex, and for sampling variability using shrinkage estimates. The corrected rate in the best 20% of NICUs was identified and NICU variations in rates were compared with those in 2000-1.

RESULTS

The overall (unadjusted) rate of severe ROP in the NICUs was 9.6% (interquartile range 5.4-12.8%). After adjusting for both case mix and sampling variability there remained significant variation among the NICUs. 20% of NICUs had a rate of severe ROP </=5.9%. Variation in rates among NICUs showed a similar pattern in both time periods. If the overall network rate was reduced to 5.9%, the 20th centile of the adjusted rates, there would be 79 fewer cases in a 2 year period, in contrast with 26 fewer if rates in the two units with excess rates improved to the average.

CONCLUSIONS

Considerable variation in rates of severe ROP among NICUs remained after adjustment for case mix and sampling variability. These data will facilitate investigation of potentially better practices associated with a reduced risk of severe ROP.

Early death, morbidity, and need of treatment among extremely premature infants

OBJECTIVE

To determine outcomes, in terms of perinatal and early death, need for treatment, and morbidity at the time of discharge home, among extremely preterm infants.

DESIGN

A prospective observational study of all infants with a gestational age (GA) of 22 to 27 completed weeks or a birth weight of 500 to 999 g who were born in Norway in 1999 and 2000.

RESULTS

Of 636 births, 174 infants (27%) were stillborn or died in the delivery room, 86 (14%) died in the NICU, and 376 (59%) were discharged from the hospital. The risk of being registered as stillborn or not being resuscitated increased with decreasing GA below 25 weeks. The survival rates for all births and for infants admitted to a NICU were, respectively, 0% for <23 weeks, 16% and 39% for 23 weeks, 44% and 60% for 24 weeks, 66% and 80% for 25 weeks, 72% and 84% for 26 weeks, 82% and 93% for 27 weeks, and 69% and 90% for >27 weeks. For the survivors, days of mechanical ventilation decreased from a median of 37 days to 3 days and the proportion in need of oxygen at 36 weeks' postconceptional age decreased from 67% to 26% at 23 and 27 weeks' GA, respectively. At 40 weeks' postconceptional age, the respective figures were 11% and 6%. The proportion with retinopathy of prematurity (ROP) requiring treatment decreased from 33% for GA of 23 weeks to 0% for >25 weeks. Periventricular hemorrhage of more than grade 2 occurred for 6% of the survivors and significant periventricular leukomalacia occurred for 5%, with no significant association with GA. The proportion of survivors without severe neurosensory or pulmonary morbidity increased from 44% for 23 weeks' to 86% for 27 weeks' GA. Apart from ROP, the morbidity rate was not associated with GA.

CONCLUSIONS

The survival rate was high and the morbidity rate at discharge home was low in the present study, compared with previous population-based studies. With the exception of ROP, the morbidity rates among the survivors were not higher at the lowest GAs, possibly because withholding treatment was considered more acceptable for the most immature infants. The need for intensive care increased markedly for survivors with the lowest GAs.

Combination therapy

OBJECTIVE

Inhibiting preterm labour at extremely early gestations.

DESIGN

Observational study. Case reports.

SETTING

Perinatal Centre Lund University Hospital, South Sweden.

POPULATION

Twenty-five women (13 cases with intact membranes and 12 cases with ruptured) with threatened preterm labour and advanced cervical status before 26 completed weeks of gestation.

METHODS

A combination of different drugs was used. Atosiban, an oxytocin antagonist, was the first line drug and was given as an infusion for several days as required. Supportive therapy was also given to most women with subcutaneous injections of the beta-receptor agonist terbutaline (0.25 mg up to six times a day); sulindac, a prostaglandin synthetase inhibitor (200 mg one to two times a day up to a week); and broad-spectrum antibiotics (metronidazole and cefuroxime intravenously for three days and thereafter oral therapy).

MAIN OUTCOME MEASURES

Prolongation of pregnancy more than 48 hours or 7 days. Neonatal survival.

RESULTS

Prolongation of pregnancy for more than 48 hours to enable administration of corticosteroid therapy was obtained in all but three cases. Eight women were delivered after more than a week from admission. Three neonates died at birth due to obstetric complication or sepsis. The other neonates had normal pH in cord or venous blood at birth. No severe side effects were recorded and in no case did the treatment have to be discontinued due to side effects.

CONCLUSION

The policy described here is not evidence based, relating only to clinical observations, and as such is of very limited value. However, it seems that with this combined approach to management, some days can be gained by achieving full effect of corticosteroid treatment and prolongation of the pregnancy, hopefully reducing time in the neonatal intensive care in these critical cases. No severe side effects were reported.

Variations in the morphology of retinopathy of prematurity in extremely low birthweight infants

AIMS

To investigate the clinical observations that arteriovenous shunts typical of threshold retinopathy of prematurity (ROP) are morphologically different in extremely low birthweight infants weighing less than 1000 g.

METHODS

An observational case series of six extremely low birthweight infants displaying specific features of threshold retinopathy of prematurity enrolled between 1998 and 2001 at one centre. The variant morphology was documented with colour photography and fundus fluorescein angiography before laser therapy.

RESULTS

Stage 3 threshold ROP in extremely premature infants may be characterised by a different morphology not demonstrating classic shunt formation. A poorly developed capillary bed is present in already vascularised retina in these cases.

CONCLUSIONS

This case series of extremely low birthweight infants display variations in the typical morphological appearance of threshold ROP. In these cases, established plus disease may be present in the absence of arteriovenous shunting. Delaying treatment until a classic stage 3 ridge with extraretinal neovascularisation develops may be detrimental to controlling the disease process. The authors propose that the criteria for threshold disease requiring treatment do not accurately apply in this extremely low birthweight group as defined by the CRYO-ROP study and that treatment should be instituted before the typical threshold features arise. Plus disease remains the most reliable sign indicating the need for treatment.

Management options for preterm labour in Canada

OBJECTIVES

(1) To determine the current use of treatment options for preterm labour and (2) to review the relative safety and efficacy of each class of tocolytic agent.

METHODS

MEDLINE and the Cochrane Library were searched using the terms "preterm delivery," "preterm labour," and "tocolysis" alone, and in combination with the terms "betamimetics," "ritodrine," "magnesium sulfate," "calcium channel blockers," "nifedipine," "prostaglandin synthetase inhibitors," "indomethacin," "glyceryl trinitrate," "nitroglycerin," "oxytocin antagonists," and "atosiban." Randomized controlled trials (RCTs) that compared the effect of a tocolytic with a placebo or other tocolytic in women with preterm labour were selected. Trials were assessed according to Jadad's validated quality scale for assessing the quality of RCTs. Thirty two RCTs retrieved met the inclusion criteria. Information not evident from RCTs was sought from non-randomized clinical trials, cohort studies, case control studies, case series, and case reports. Data from the Canadian Survey on Tocolytic Use was obtained directly from the Society of Obstetricians and Gynaecologists of Canada (SOGC).

RESULTS

The available evidence on the use of tocolytics to prolong pregnancy fails to show benefits in neonatal survival and reduced disability. This uncertainty of benefit makes the issue of fetal and maternal drug toxicity more important. There is great concern among SOGC members over the lack of effective and safe treatment options for the management of preterm labour.

CONCLUSIONS

Further well-designed placebo-controlled trials are necessary to study the efficacy and safety of tocolytics in managing preterm labour.

Proactive management promotes outcome in extremely preterm infants: a population-based comparison of two perinatal management strategies

OBJECTIVE

There is a need for evidence-based knowledge regarding perinatal management in extreme prematurity. The benefit of a proactive attitude versus a more selective one is controversial. The objective of the present study was to analyze perinatal practices and infant outcome in extreme prematurity in relation to different management policies in the North (proactive) and South of Sweden.

METHODS

A population-based, retrospective, cohort study design was used. Data in the Swedish Medical Birth Register (MBR) from 1985 to 1999 were analyzed according to region of birth and gestational age (22 weeks + 0 days to 27 weeks + 6 days). A total of 3 602 live-born infants were included (North = 1040, South = 2562). Survival was defined as being alive at 1 year. Morbidity in survivors, based on discharge diagnoses of major morbidity during the first year of life, was described by linking the MBR to the Hospital Discharge Register.

RESULTS

In infants with a gestational age of 22 to 25 weeks, the proactive policy was significantly associated with 1) increased incidence of live births, 2) higher degree of centralized management, 3) higher frequency of caesarean section, 4) fewer infants with low Apgar score (<4) at 1 and 5 minutes, 5) fewer infants dead within 24 hours, and 6) increased number of infants alive at 1 year. There were no indications of increased morbidity in survivors of the proactive management during the first year of life, and the proportion of survivors without denoted morbidity was larger.

CONCLUSION

In infants with a gestational age of 22 to 25 weeks, a proactive perinatal strategy increases the number of live births and improves the infant's postnatal condition and survival without evidence of increasing morbidity in survivors up to 1 year of age.

Fetal infants: the fate of 4172 infants with birth weights of 401 to 500 grams--the Vermont Oxford Network experience (1996-2000)

OBJECTIVE

Improvement in the survival of extremely low birth weight infants requires that we evaluate the limits of our care and assess the impact of treatment on a population of infants who previously rarely survived.

METHODS

A review was conducted of demographic and clinical data of infants who had birth weight 401 to 500 g and were entered in the Vermont Oxford Network Database between 1996 and 2000.

RESULTS

A total of 4172 infants who weighed 401-500 g (mean gestational age: 23.3 +/- 2.1 weeks) were born at 346 participating centers. Overall, 17% survived until discharge. A total of 2186 (52%) died in the delivery room (DR), and 1986 (48%) were admitted to a neonatal intensive care unit (NICU). Compared with infants who died in the DR, infants who survived the DR and were admitted to the NICU were more likely to be female (58% vs 49%), to be small for gestational age (56% vs 11%), to have received prenatal steroids (61% vs 12%), and to have been delivered by cesarean section (55% vs 5%). Thirty-six percent of NICU admissions survived to discharge. Mean gestational age of the 690 NICU survivors was 25.3 +/- 2.0 weeks. These survivors experienced significant morbidity in the NICU.

CONCLUSIONS

An appreciable number of these marginally viable fetal infants survive. They experienced a high rate of serious morbidities while in the NICU. There is very little information about long-term outcomes, as the medical and developmental status of few of these infants has been followed carefully. Parents should be made aware of the high incidence of serious problems, and concerted efforts should be made to follow the status of these infants.

Preterm delivery, level of care, and infant death in sweden: a population-based study

OBJECTIVE

To elucidate the role of level of care in combination with other perinatal risk factors for infant death in very preterm deliveries.

DESIGN

Population-based cohort study.

SETTING

Sweden, 1992-1998.

SUBJECTS

Singleton infants (2285) born at 24 to 31 completed weeks of gestation to primiparous women.

MAIN OUTCOME MEASURE

Infant mortality.

RESULTS

The rate of infant mortality increased from 5% among infants born at 31 weeks' gestation to 56% among infants born at 24 weeks' gestation. Compared with infants born at university hospitals, the unadjusted odds ratio (OR) of infant death was 0.70 (95% confidence interval [CI]: 0.54-0.90) among infants delivered at general hospitals. However, after adjustment, the OR of infant death shifted to 1.33 (95% CI: 0.88-2.02) for preterm births at general hospitals. This shift was primarily due to different gestational age distributions in regional and general hospitals. Among infants born at 24 to 27 weeks' gestation, infant mortality rates were 23% (87 deaths) in university hospitals and 32% (73 deaths) in general hospitals, giving an adjusted OR of 2.00 for general versus university hospitals (95% CI: 1.15-3.49). The risk of death at 24 to 27 weeks' gestation in general hospitals was increased specifically in pregnancies with placental complications.

CONCLUSION

Taking obstetric complications into account, there is an excess mortality risk among extremely preterm infants born at general hospitals.

Regionalization of perinatal care in Europe

This review describes European health policies related to the place of birth of very preterm babies, and the organizational context in which these policies were enacted using data from two European studies. It also compiles available information on the place of birth of very preterm babies from the published literature. In Europe, there is significant diversity in approaches to the provision of intensive care services for the small proportion of pregnant women and babies that need it, both in terms of health policies and the supply and characteristics of maternity and neonatal units. These diverse models in countries with similar levels of development and medical technology could offer an opportunity to understand how different organizational characteristics affect access to care, health outcomes and resource use.

Critères de réanimation des prématurissimes en salle de naissance : quel discours en anténatal ?

The resuscitation of extremely preterm infants presents complex medical, social and ethical issues for the families and the health professionals. The principle of a systematic resuscitation "temporary intensive care" does not prohibit the question of a limit in terms of gestational age and birth weight. In France, a do not resuscitate order (comfort care alone) is appropriate for newborns weighing less than 500g and/or with a gestational age of less than 24 weeks' since the mortality is nearly 100%. The survival of infants born at 24 weeks' gestational age remains low with significant risks of chronic medical problems and neurodevelopmental disabilities. The decisions regarding the extent of resuscitative efforts depend on antenatal factors, condition of the neonate at birth and the parental opinion. Before the delivery, parents should receive appropriate information about survival and risks of adverse long-term outcome. The physician should follow the parents' desires whenever the parents' decision would not obviously violate the infants' best interests. However, they must be informed that decisions about neonatal management made before the delivery can have to be changed in the delivery room, depending on the condition of the neonate at birth. At 25 weeks of gestational age, the prognosis is better and the resuscitation should be more intensive.

Guidelines for resuscitation in the delivery room of extremely preterm infants

Ethical problems related to intensive care of extremely preterm newborns of < or = 25 weeks' gestational age and at risk of disability have been extensively debated. The Bioethical Committee of the Department of Paediatrics of the University Hospital of Padua organized and started a multidisciplinary group to release guidelines to help staff facing problems related to prematurity. The vitality limit, survival, outcome, and ethical aspects were analyzed. Consequently, we suggest the following: at 22 weeks' gestational age, the deliverance of comfort care only; at 23 weeks, in the presence of detectable vital signs, the practice of immediate intubation, respiratory support, and a reassessment of the neonatal conditions; and at 24 weeks, the provision of intubation, ventilatory support, and cardiovascular resuscitation. If the clinical age and anamnestic gestational age are different, we proceed according to the more advanced one. The importance of providing parents with correct information and the role of comfort care are outlined.

Associations between perinatal interventions and hospital stillbirth rates and neonatal mortality

BACKGROUND

Previous studies suggest that high risk and low birthweight babies have better outcomes if born in hospitals with level III neonatal intensive care units. Relations between obstetric care, particularly intrapartum interventions and perinatal outcomes, are less well understood, however.

OBJECTIVE

To investigate effects of obstetric, paediatric, and demographic factors on rates of hospital stillbirths and neonatal mortality.

METHODS

Cross sectional data on all 65 maternity units in all Thames Regions, 1994-1996, covering 540 834 live births and stillbirths. Hospital level analyses investigated associations between staffing rates (consultant/junior paediatricians, consultant/junior obstetricians, midwives), facilities (consultant obstetrician/anaesthetist sessions, delivery beds, special care baby unit, neonatal intensive care unit cots, etc), interventions (vaginal births, caesarean sections, forceps, epidurals, inductions, general anaesthetic), parental data (parity, maternal age, social class, deprivation, multiple births), and birthweight standardised stillbirth rates and neonatal mortality.

RESULTS

Unifactorial analyses showed consistent negative associations between measures of obstetric intervention and stillbirth rates. Some measures of staffing, facilities, and parental data also showed significant associations. Scores for interventional, organisational, and parental variables were derived for multifactorial analysis to overcome the statistical problems caused by high intercorrelations between variables. A higher intervention score and higher number of consultant obstetricians per 1000 births were both independently and significantly associated with lower stillbirth rates. Organisational and parental factors were not significant after adjustment. Only Townsend deprivation score was significantly associated with neonatal mortality (positive correlation).

CONCLUSIONS

Birthweight adjusted stillbirth rates were significantly lower in units that took a more interventionalist approach and in those with higher levels of consultant obstetric staffing. There were no apparent associations between neonatal death rates and the hospital factors measured here.

Management decisions in extremely premature infants

Survival rates in excess of 25% at 23 weeks' gestation and in excess of 50% at 24 weeks' gestation have been reported among live births in the 1990s within tertiary perinatal care centres in the USA and Australia. Decisions about medical management at these gestational ages can no longer be based merely on whether survival is possible. Relevant moral considerations include the primacy of the newborn's best interests, parental autonomy, physicians' duties of beneficence and non-maleficence, and distributive justice. There is significant variability between developed nations in the survival of extremely premature infants among cohorts born within perinatal tertiary care centres. This is, at least to some degree, the result of differences in the aggressiveness of obstetrical and neonatal management at these gestational ages. There is also great variability in the prevalence of major neurodevelopmental disability among survivors. Moreover, the prevalence of major disabilities does not inform quality-of-life considerations adequately. Despite similar gestational age ranges over which the benefit:burden ratio of aggressive obstetric and neonatal care is questioned in developed countries, there is marked variation in the frequency with which it is provided within these ranges. This is understandable given the relevant moral values and the different ways in which competing values will be balanced by different individuals, cultures and societies; the increasing survival of extremely premature infants, but the persistence of high (but widely variable) prevalences of major disabilities reported among survivors and even higher prevalences of mild-to-moderate neurodevelopmental sequelae; our imperfect ability to estimate an individual extremely premature infant's prognosis; and the complexities of estimating the quality of life from the individual's own perspective.

Mortality and neurologic, mental, and psychomotor development at 2 years in infants born less than 27 weeks' gestation: the Leiden follow-up project on prematurity

OBJECTIVE

To determine the outcome of infants with a gestational age (GA) <27 weeks, born in the mid-1990s.

DESIGN

Regional, prospective study; part of the Leiden Follow-Up Project on Prematurity.

SETTING

Three health regions in The Netherlands.

PATIENTS

A total of 266 live born infants (1996/1997) with GA <32 weeks; 46 infants were <27 weeks.

MAIN OUTCOME MEASURES

Neurologic examination (according to Hempel) and assessment of mental and psychomotor development using the Bayley Scales of Infant Development I, at the corrected age of 2 years.

RESULTS

Mortality was 35% (16 of 46) <27 weeks, compared with 6% (14 of 220) in infants with GA 27 to 32 weeks; withdrawal of treatment in 60% and 43%, respectively. Below 27 weeks mortality was higher after extra-uterine transport and pregnancy induction. Neonatal morbidity was higher in infants <27 weeks compared with infants 27 to 32 weeks. Below 27 weeks postnatal use of dexamethasone and being hospitalized at term were associated with abnormal neurologic outcome; there was a higher incidence in (mild) mental developmental delay compared with the older infants. Adverse outcome (dead or abnormal neurologic, psychomotor, or mental development) in infants 23 to 24, 25, 26, and 27 to 32 weeks GA was, respectively, 92% (11 of 12), 64% (7 of 11), 35% (8 of 23), and 18% (40 of 220).

CONCLUSIONS

Mortality and neonatal morbidity were higher in infants with GA <27 weeks compared with infants born between 27 and 32 weeks. The high adverse outcome of infants <25 weeks suggests that one should carefully weigh whether or not to aggressively resuscitate and treat these extremely premature infants.

Preterm delivery: an overview

Preterm delivery is the leading factor causing neonatal mortality and morbidity. We have conducted a PubMed literature search to obtain an update on the etiology, diagnostic problems and therapeutic considerations of preterm delivery. Approximately 5-10% of all births are premature. Preterm labor is associated with preterm rupture of membranes, cervical incompetence, polyhydramnion, fetal and uterine anomalies, infections, social factors, stress, smoking, heavy work and other risk factors. The diagnosis is made on the patients presenting symptoms, clinical findings and of progressive effacement and dilatation of the cervix. Biochemical markers of preterm delivery are of minor importance in daily clinical work. Measurement of the cervix, however, is a practical and valuable tool to predict preterm delivery. Cervical cerclage can be useful in selected cases. Antibiotics may help to prevent preterm labor in cases of known etiologic agents (e.g. preterm rupture of membranes and urinary infection). The use of tocolytic agents such as beta-sympathetic receptor stimulators can be advocated for a few days. There is evidence that their long-term use is not beneficial and could even be harmful to the fetus. Calcium channel blockers (nifedipine) and a new selective oxytocin receptor antagonist, atosiban, appear to be as effective as beta-sympathomimetic drugs on uterine contractions with fewer side-effects. Prostaglandin synthetase inhibitors such as indomethacin may prevent uterine contractions and can be used prior to the 32nd week of pregnancy. A single course of corticosteroid treatment in two doses of 12 mg betamethasone or 6 mg of dexamethasone is important for the prevention of respiratory distress between the 24th and 34th weeks of pregnancy. Multiple doses may be harmful and should be avoided. In these cases management should depend on gestation age (fetal maturity). Uterine contractions after 34 weeks' gestation are not an indication for tocolytic treatment.

Significant delay of birth in advanced preterm labour at 23 gestational weeks with an oxytocin antagonist

CASE

A 27-year-old primigravid woman with advanced preterm labour at 23 weeks and 5 days gestation received tocolytic therapy with a continuous infusion of the oxytocin antagonist, atosiban, during 154 h. The delivery was postponed for 12 days. The baby was discharged after 3 months of neonatal care and at 6 months of age is healthy. The prolonged treatment was not associated with maternal or fetal side effects.

Recent evidence associated with the condition of preterm prelabour rupture of the membranes

PURPOSE OF REVIEW

The published literature on preterm prelabour rupture of the membranes is voluminous yet despite advances in obstetric and neonatal care, the problem remains a major cause of perinatal mortality and morbidity. The purpose of this review is to present recent evidence pertaining to the role of inflammatory mediators such as cytokines and the tissue damage and long-term handicap they cause, the molecular biology and physiology of membrane structure, the role of host susceptibility and the genetics of preterm birth and therapeutic options for the management of preterm prelabour rupture, including antibiotics, amnioinfusion and special situations.

RECENT FINDINGS

Neonatal morbidity from preterm prelabour rupture of the membranes is mainly related to oligohydramnios and pulmonary hypoplasia. Occupational factors have a significant effect on the occurrence and outcome following rupture. Matrix metalloproteinases control growth and remodelling of the pregnant uterus, placenta and membranes and are linked to a genetic predisposition to preterm birth through gene expression and variation. Transvaginal ultrasound scan, oncofetal fibronectin and the presence of abnormal genital tract flora (bacterial vaginosis) in pregnancy may help in the prediction of preterm birth.

SUMMARY

Preterm prelabour membrane rupture remains a management problem, particularly at very early gestations, yet obstetric and neonatal care can make a difference to outcome. While at early gestations the prognosis is poor, it is not hopeless. Careful selection of the recent literature on the subject might interest and inform those faced regularly with the problem, prevent therapeutic nihilism, promote confidence in our ability to make a difference and realise that we are not alone when faced with the therapeutic dilemma that is this condition.

A national two year follow up study of extremely low birthweight infants born in 1996-1997

OBJECTIVE

To study neurodevelopmental outcome in a two year cohort of extremely low birthweight (ELBW) infants at 18 months corrected age, to compare the development of the ELBW infant subcohort with that of control children, and to find risk factors associated with unfavourable outcome.

STUDY DESIGN

All 211 surviving ELBW infants (birth weight < 1000 g) born in Finland in 1996-1997 were included in a national survey. The ELBW infants (n = 78) who were born and followed in Helsinki University Hospital belonged to a regional subcohort and were compared with a control group of 75 full term infants. A national follow up programme included neurological, speech, vision, and hearing assessments at 18 months of corrected age. Bayley infant scale assessment was performed on the subcohort and their controls at 24 months of age. Risk factors for unfavourable outcome were estimated using logistic and linear regression models.

RESULTS

The prevalence of cerebral palsy was 11%, of all motor impairments 24%, of ophthalmic abnormalities 23%, and of speech delay 42%. No impairment was found in 42% of children, and 18% were classified as severely impaired. The prevalence of ophthalmic abnormalities decreased with increasing birth weight and gestational age, but the prevalence of other impairments did not. In the subcohort, a positive correlation was found between the date of birth and Bayley scores.

CONCLUSION

Ophthalmic abnormalities decreased with increasing birth weight and gestational age, but no other outcome differences were found between birthweight groups or in surviving ELBW infants born at 22-26 weeks gestation. The prognosis in the regional subcohort seemed to improve during the short study period, but this needs to be confirmed.

An update on the controversies of tocolytic therapy for the prevention of preterm birth

Preterm birth is the major cause of perinatal mortality and morbidity in the developed world. Where there are no contraindications to their use, tocolytics can improve neonatal survival rates by approximately 3% per day between 23 and 27 weeks gestation with a concomitant reduction in morbidity. The ultimate aim of tocolytic therapy is to prolong pregnancy until growth and maturation is complete, but even short-term delay may enable the administration of antepartum glucocorticoids to reduce hyaline membrane disease or to arrange transfer to a center with neonatal intensive care facilities. Both of these have been shown to reduce neonatal mortality and morbidity. Until recently, none of the currently used tocolytics, whether licensed or unlicensed, were developed specifically for the inhibition of preterm labor and consequently, they exhibit various potentially serious side-effects. As a result of the recent licensing of the oxytocin antagonist, atosiban, developed for the treatment of preterm labor and due to its high utero-specificity, obstetricians have experienced an advance in their options for the management of spontaneous preterm labor.

Outcomes for high risk New Zealand newborn infants in 1998-1999: a population based, national study

OBJECTIVE

To determine short term morbidity and mortality outcomes, provision of care, and treatments for a national cohort of high risk infants born in 1998-1999 and admitted to New Zealand neonatal intensive care units (NICUs).

SETTING

All level III (six) and level II (13) NICUs in New Zealand.

METHODS

Prospective audit by the Australian and New Zealand Neonatal Network (ANZNN) of all infants defined as "high risk" (born at < 32 weeks gestation or < 1500 g birth weight, or received assisted ventilation for four hours or more, or had major surgery). Data were collected from birth until discharge home or death.

RESULTS

There were 3368 high risk infants (3.0% of all live births), comprising 1241 (37%) < 32 weeks gestation, 1084 (32%) < 1500 g, 3156 (94%) who received assisted ventilation, and 243 (7%) who received major surgery (categories overlap). Most infants (87%) received some care in tertiary hospitals, and 13% were cared for entirely in non-tertiary hospitals. Survival was 91% for infants < 32 weeks gestation, 97% for infants > or = 32 weeks gestation who received assisted ventilation, and 92% for infants > or = 32 weeks gestation who had major surgery. The proportion of very preterm infants who survived free of early major morbidity was 11%, 28%, 53%, 81%, and 90% for infants born at < 24, 24-25, 26-27, 28-29, and 30-31 weeks gestation respectively.

CONCLUSIONS

These unique population based national data provide contemporary information on the care and early morbidity and mortality outcomes for all high risk infants, whether cared for in hospitals with level III or level II NICUs.

Improved outcomes for very low birthweight infants: evidence from New Zealand national population based data

OBJECTIVE

To compare the survival and short term morbidity of all New Zealand very low birthweight (VLBW) infants born in two epochs, 1986 and 1998-1999.

SETTING

All level III and level II neonatal intensive care units (NICUs) in New Zealand.

METHODS

In 1986, data were prospectively collected for a study of retinopathy of prematurity (ROP). In 1998-1999, prospective data were collected by the Australian and New Zealand Neonatal Network (ANZNN). Both cohorts included all VLBW infants born during the calendar year and admitted to a NICU. Data were collected from birth until discharge home or death.

RESULTS

More VLBW infants were admitted for care in 1998-1999 (n = 1084, 0.96% of livebirths) than in 1986 (n = 413, 0.78% of livebirths; p < 0.001), including a higher proportion of VLBW infants of < 1000 g birth weight (38% v 32% respectively; p < 0.05). Survival to discharge home increased from 81.8% in 1986 to 90.3% in 1998-1999 (p < 0.001). The 1998-1999 cohort had a higher proportion of infants born in a hospital with a level III NICU (87% v 72% in 1986; p < 0.001) and receiving antenatal corticosteroids (80% v 58% in 1986; p < 0.001). In 1998-1999, the incidence of several morbidities had decreased compared with 1986, including oxygen dependency at 28 days (29% v 39% respectively; p = 0.001) and at 36 weeks postmenstrual age (16% v 23%; p = 0.002), grade 1 intraventricular haemorrhage (IVH) (8% v 24%; p < 0.001), grade 2/3 IVH (5% v 11%; p < 0.001), and stage 3/4 ROP for infants < 1000 g (6% v 13%; p < 0.001).

CONCLUSIONS

The outlook for VLBW infants in New Zealand has improved since 1986.

Preterm delivery

Preterm delivery and its short-term and long-term sequelae constitute a serious problem in terms of mortality, disability, and cost to society. The incidence of preterm delivery, which has increased in recent years, is associated with various epidemiological and clinical risk factors. Results of randomised controlled trials suggest that attempts to reduce these risk factors by use of drugs are limited by side-effects and poor efficacy. An improved understanding of the physiological pathways that regulate uterine contraction and relaxation in animals and people has, however, helped to define the complex processes that underlie parturition (term and preterm), and has led to new scientific approaches for myometrial modulation. The continuing elucidation of the mechanisms that regulate preterm labour, combined with rigorous clinical assessment, offer hope for future solutions.

Comparison of the prediction of extremely low birth weight neonatal mortality by regression analysis and by neural networks

AIMS

To compare the prediction of mortality in individual extremely low birth weight (ELBW) neonates by regression analysis and by artificial neural networks.

STUDY DESIGN

A database of 23 variables on 810 ELBW neonates admitted to a tertiary care center was divided into training, validation, and test sets. Logistic regression and neural network models were developed on the training set, validated, and outcome (mortality) predicted on the test set. Stepwise regression identified significant variables in the full set. Regression models and neural networks were then tested using data sets with only the identified significant variables, and then with variables excluded one at a time.

RESULTS

The area under the curve (AUC) of receiver operating characteristic (ROC) curves for neural networks and regression was similar (AUC 0.87+/-0.03; p=0.31). Birthweight or gestational age and the 5-min Apgar score contributed most to AUC.

CONCLUSIONS

Both neural networks and regression analysis predicted mortality with reasonable accuracy. For both models, analyzing selected variables was superior to full data set analysis. We speculate neural networks may not be superior to regression when no clear non-linear relationships exist.

Retinopathy of prematurity: clinical aspects

There have been many major advances recently that have improved the identification and management of retinopathy of prematurity (ROP). This chapter describes the clinical features of ROP and then considers briefly the incidence and epidemiology of acute phase disease. This is followed by a discussion of the two ROP epidemics and ROP-induced disability in high, low and middle income countries, and how this has been impacted by treatment. The principles and specifics of screening for ROP are considered, focusing on certain topical issues such as whether one screening guideline suits all populations. Treatment has undergone several advances, so that now laser therapy has overtaken cryotherapy as the preferred mode of treatment, and treatment at an earlier stage is now being considered. Finally, the authors attempt to look into the future and wonder how the criteria for treatment will change, and whether innovations in ocular imaging will impact ROP screening in both high and middle income countries.