Neonatal outcome of very premature infants from multiple and singleton gestations

Predictors of a non-response to prophylactic indomethacin for patent ductus arteriosus in preterm infants

BACKGROUND

Preterm infants are recommended for prophylactic indomethacin (PIND) to promote closure of patent ductus arteriosus (PDA) and reduce morbidity and mortality. This study investigated the predictive factors of a non-response to PIND for PDA in preterm-birth infants.

METHODS

Consecutive preterm-birth infants (gestational age: < 28 weeks) who received PIND between 2009 and 2019 were retrospectively enrolled. Seventy-six eligible participants were classified as PIND responders (N = 42) or non-responders (N = 34). Information on potential confounders in maternal obstetric and perinatal data were collected from medical records. Multiple logistic regression analysis was carried out to identify the prognostic factors of a PIND response in preterm-birth infants.

RESULTS

The prevalence of intrauterine infection and multiple births was significantly different between responders and non-responders to PIND (intrauterine infection: 2 [4.8%] vs. 8 [23.5%], P = 0.036; twins: 3 [7.1%] vs. 9 [ 26.5%], P = 0.029, respectively). In multivariate logistic regression analysis after adjustment for multiple births, intrauterine infection was a significant and independent predictive factor of a non-response to PIND (odds ratio [OR] 5.54, 95% confidence interval [CI] 1.05-29.2, P = 0.044). A remarkable association was also noted for multiple births with a non-response to PIND (OR 4.22, 95% CI 0.99-17.8, P = 0.050).

CONCLUSIONS

Intrauterine infection and multiple births were identified as potential risk factors of a non-response to PIND for PDA in preterm infants.

Single Center Outcome of Multiple Births in the Premature and Very Low Birth Weight Cohort in Singapore

OBJECTIVE

The aim of this study is to compare neonatal mortality and morbidity in multiple and singleton preterm/very low birthweight (PT/VLBW) multiethnic Asian infants.

STUDY DESIGN

Cohort study of 676 singleton and 299 multiple PT/VLBW infants born between 2008 and 2012 at KK Women's and Children's Hospital, the largest tertiary perinatal center in Singapore with further stratification by gestational ages 23 to 25 (Group 1), 26 to 28 (Group 2), and ≥29 (Group 3) weeks. Outcome measures included predischarge mortality and major neonatal morbidity.

RESULTS

Overall survival to discharge was comparable for singletons 611/676 (90%) and multiples 273/299 (91%). Use of assisted reproductive technologies (47 vs. 4%), antenatal steroids (80 vs. 68%), and delivery by cesarean section (84 vs. 62%) were significantly higher (p < 0.001) in multiples while pregnancy induced hypertension (8.7 vs. 31.6%, p < 0.001) and maternal chorioamnionitis (31 vs. 41%, p < 0.01) were seen less commonly compared with singleton pregnancies. Survival was comparable between singletons and multiples except for a lower survival in multiples in Group 2 (81.7 vs. 92.4%, p = 0.007). Major neonatal morbidities were comparable for multiples and singletons in the overall cohort. Presence of hemodynamically significant patent ductus arteriosus (HsPDA) requiring treatment (88.9 vs. 72.5%), air leaks (33 vs. 14.6%, p = 0.02), NEC (30 vs. 14.6%, p = 0.04), and composite morbidity (86 vs. 66%, p = 0.031) were significantly higher in multiples in Group 1. A significantly higher incidence of HsPDA (68.1 vs. 52.4%, p = 0.008) was also observed in multiples in Group 2. Multiple pregnancy was not an independent predictor of an adverse outcome on regression analysis (OR: 0.685, 95% confidence interval: 0.629-2.02) even in GA ≤25 weeks.

CONCLUSION

Neonatal mortality and morbidity were comparable in our cohort of PT/VLBW singletons and multiple births, but preterm multiple births ≤25 weeks had a higher incidence of neonatal morbidity.

KEY POINTS

· Use of assisted reproductive technologies was significantly higher in multiples as compared to singletons.. · Major neonatal morbidities and mortality were similar between singletons and multiples in our cohort.. · In gestations less than 25 weeks multiples had higher neonatal morbidities than their singleton counterparts..

Triplet pregnancy: What do we tell the prospective parents

Experience managing triplet pregnancies has increased over the past few decades as the incidence has changed related to assisted reproductive practices. Physicians caring for women carrying triplets cannot predict an individual outcome or pregnancy course but must educate patients about the challenges related to these high risk pregnancies. Obstetric providers can describe the wide range of risks associated with triplet gestations, and the general plan for management, but ultimately parents must make decisions with potentially lifelong consequences. Here, we present the diagnostic criteria, common complications, and management options for triplet pregnancies, to help obstetricians counsel patients on the medical and psychosocial consequences of triplet pregnancy, potential complications, and multifetal reduction.

Low mortality and short-term morbidity in very preterm infants in Austria 2011-2016

AIM

The current study determined survival, short-term neonatal morbidity and predictors for death or adverse outcome of very preterm infants in Austria.

METHODS

This population-based cohort study included 5197 very preterm infants (53.3% boys) born between 2011 and 2016 recruited from the Austrian Preterm Outcome Registry. Main outcome measures were gestational age-related mortality and major short-term morbidities.

RESULTS

Overall, survival rate of all live-born infants included was 91.6% and ranged from 47.1% and 73.4% among those born at 23 and 24 weeks of gestation to 84.9% and 88.2% among infants born at 25 and 26 weeks to more than 90.0% among those with a gestational age of 27 weeks or more. The overall prevalence of chronic lung disease, necrotising enterocolitis requiring surgery, intraventricular haemorrhage Grades 3-4, and retinopathy of prematurity Grades 3-5 was 10.0%, 2.1%, 5.5%, and 3.6%, respectively. Low gestational age, low birth weight, missing or incomplete course of antenatal steroids, male sex, and multiple births were significant risk predictors for death or adverse short-term outcome.

CONCLUSION

In this national cohort study, overall survival rates were high and short-term morbidity rate was low.

Risk factors for failure in the newborn hearing screen test in very preterm twins

BACKGROUND

We aimed to identify prenatal and postnatal risk factors associated with abnormal newborn hearing screen (NHS) results and subsequently confirmed sensorineural hearing loss (SNHL) in preterm twin neonates.

METHODS

Electronic medical records of 159 twin neonates who were born alive after ≤32 weeks were retrospectively reviewed for hearing loss in both ears. Histopathologic examination of the placenta was performed and clinical data, including method of conception and factors specific to twins, were retrieved from a computerized perinatal database. The main outcome measure was failure to pass the NHS test. The generalized estimation equations model was used for twins.

RESULTS

Thirty-two neonates (20.1%) had a "refer" result, and, on the confirmation test, permanent SNHL was identified in 4.4% (7/159) of all neonates. Neonates who had a "refer" result on the NHS test were more likely to be of lower birth weight, more likely to have been conceived with the use of in vitro fertilization (IVF), and more likely to have higher rates of intraventricular hemorrhage (IVH) and bronchopulmonary dysplasia. However, monochorionic placentation, death of the co-twin, or being born first was not associated with a "refer" result on the NHS test. Multivariable logistic regression revealed that conception after IVF and the presence of IVH were the only variables to be statistically significantly associated with "refer" on the NHS test. No parameters studied were found to be significantly different between the SNHL and no SNHL groups, probably because of the relatively small number of cases of SNHL.

CONCLUSION

In preterm twin newborns, IVF and the presence of IVH were independently associated with an increased risk of abnormal NHS results, whereas the factors specific to twins were not associated with abnormal NHS results.

Attenuation of ductus arteriosus intimal thickening in preterm sheep twins compared with singletons

Preterm twins have a higher morbidity rate of patent ductus arteriosus (PDA) than do singletons. However, the effect of multiple births on maturation of the ductus arteriosus (DA) has not been reported. Because intimal thickening (IT) is required for DA anatomical closure, we examined IT development in the DA of preterm twins and singletons. Sheep DA tissues obtained from preterm fetuses were subjected to elastica van Gieson staining to evaluate IT. The total IT score in each DA was the sum of the IT scores obtained from six evenly divided parts of the DA, which was positively correlated with gestational ages in singletons. Total IT scores were smaller in preterm twins than in singletons, although no difference in gestational age, birth weight, or gender ratio was observed. These data suggest that IT development of the DA is attenuated in sheep preterm twins, which may affect the higher morbidity of PDA.

Risk Factors for Cause-specific Mortality of Very-Low-Birth-Weight Infants in the Korean Neonatal Network

This study attempted to assess the risk factors for mortality of very-low-birth-weight (VLBW) infants in the neonatal intensive care unit (NICU, n=2,386). Using data from the Korean Neonatal Network, we investigated infants with birth weights <1,500 g and gestational ages (GAs) of 22-31 weeks born between January 2013 and June 2014. Cases were defined as death at NICU discharge. Controls were randomly selected from live VLBW infants and frequency matched to case subjects by GA. Relevant variables were compared between the cases (n=236) and controls (n=236) by Cox proportional hazards regression to determine their associations with cause-specific mortality (cardiorespiratory, neurologic, infection, gastrointestinal, and others). In a Cox regression analysis, cardiorespiratory death were associated with a foreign mother (hazard ratio, HR, 4.33; 95% confidence interval, CI, 2.08-9.02), multiple gestation (HR, 1.65; 95% CI, 1.07-2.54), small for gestational age (HR, 2.06; 95% CI, 1.25-3.41), male gender (HR, 1.69; 95% CI, 1.10-2.60), Apgar score ≤3 at 5 min (HR, 1.97; 95% CI, 1.18-3.31), and delivery room resuscitation (HR, 2.60; 95% CI, 1.53-4.40). An Apgar score ≤3 at 5 min was also associated with neurological death (HR, 2.95; 95% CI, 1.29-6.73). Death due to neonatal infection was associated with outborn delivery (HR, 5.09; 95% CI, 1.46-17.74). Antenatal steroid and preterm premature rupture of membranes reduced risk of cardiorespiratory death (HR, 0.43; 95% CI, 0.27-0.67) and gastrointestinal death (HR, 0.30; 95% CI, 0.13-0.70), respectively. In conclusion, foreign mother, multiple gestation, small gestation age, male gender, Apgar score ≤3 at 5 min, and resuscitation in the delivery room are associated with cardiorespiratory mortality of VLBW infants in NICU. An Apgar score ≤3 at 5 min and outborn status are associated with neurological and infection mortality, respectively.

Trends in Morbidity and Mortality of Extremely Preterm Multiple Gestation Newborns

OBJECTIVES

To examine the risk of mortality and major morbidities in extremely preterm multiple gestation infants compared with singletons over time.

METHODS

This is a retrospective study of 15,402 infants born ≤27 weeks' gestation, admitted to NICUs in the Australian and New Zealand Neonatal Network from 1995 to 2009. Mortality and major morbidities were compared between singletons and multiples across three 5-year epochs.

RESULTS

Extreme preterm multiples were more likely to have lower birth weight; higher maternal age; and higher rates of assisted conception, antenatal steroid use, and cesarean delivery compared with singletons. The mortality rate was significantly higher in multiples compared with singletons even as there was a trend of decreasing gestational-age stratified mortality in multiples over the time period investigated. The rates of major morbidities or composite adverse outcomes were not different between multiples and singletons across all epochs. The adjusted odds ratio (AOR) for mortality in multiples was significantly higher in multiples compared with singletons (AOR 1.20, 95% confidence interval [CI] 1.08-1.34). There were no differences in the adjusted odds for poor outcomes in multiples compared with singletons in the most recent epoch: mortality (AOR 1.00, 95% CI 0.84-1.19), major morbidity (0.95, 95% CI 0.81-1.10), and composite adverse outcome (0.96, 95% CI 0.83-1.11).

CONCLUSIONS

Over the 15-year period, the odds for mortality in extremely preterm NICU infants of multiple gestation was significantly higher compared with singletons. The adjusted odds of poor outcomes in multiples were not significantly different from that of singletons in the most recent epoch.

Neurodevelopmental outcomes of preterm singletons, twins and higher-order gestations: a population-based cohort study

OBJECTIVE

To study the neurodevelopmental outcomes of multiple (twins, triplets, quads) compared with singleton extremely preterm infants <29 weeks gestation.

DESIGN

Population-based retrospective cohort study.

SETTING

A network of 10 neonatal intensive care units in a geographically defined area of New South Wales and the Australian Capital territory.

PATIENTS

1473 infants <29 weeks gestation born between 1 January 1998 and 31 December 2004.

INTERVENTION

At 2-3 years of corrected age, a neurodevelopmental assessment was conducted using either the Griffiths Mental Developmental Scales or the Bayley Scales of Infant Development II.

MAIN OUTCOME MEASURE

Moderate-severe functional disability was defined as developmental delay (Griffiths Mental Developmental Scales General Quotient or Bayley Scales of Infant Development-II Mental Development Index >2 SDs below the mean), moderate cerebral palsy (unable to walk without aids), sensorineural or conductive deafness (requiring amplification) or bilateral blindness (visual acuity <6/60 in the better eye).

RESULTS

Of the 1081 singletons and 392 multiples followed-up, singletons demonstrated higher rates of systemic infections, steroid treatment for chronic lung disease and birth weight <10th percentile. Moderate-severe functional disability did not differ significantly between singletons and multiples (15.8% vs 17.6%, OR 1.14; 95% CI 0.84 to 1.54; p=0.464). Further subgroup analysis of twins, higher-order gestations, 1st-born multiples, 2nd or higher-born multiples, same and unlike gender multiples, did not demonstrate statistically higher rates of functional disability compared with singletons.

CONCLUSIONS

Premature infants from multiple gestation pregnancies appear to have comparable neurodevelopmental outcomes to singletons.

Perinatal Outcome of Twins Compared to Singletons of the Same Gestational Age: A Case-Control Study

Our objective was to determine the perinatal outcome of first- and second-born twins compared to singletons, born at the same gestational age. To that end we conducted a case-control study in Flanders (Northern Belgium). During a 10-year period (01.01.1999–31.12.2008), the entire twin population — 11,154 first- and 11,118 second-born twins (cases) — was compared to 22,228 singletons (controls) with respect to fetal and neonatal (0–27 days) mortality. Only case and control infants of ≥ 500 grams were included, which explained the unequal number of first- and second-born twins. Mothers and their infants of cases and of controls were derived from the Flemish perinatal database and were matched for maternal age and parity, gestational age and gender of the offspring. The main outcome measures were fetal and neonatal mortality according to gestational age. The frequency of fetal death was statistically significantly less frequent in preterm born twins than in singletons, except at term where the reverse was seen in second-born twins compared to controls. After adjustment for congenital malformations, the results stayed unchanged. Below 28 weeks gestation, singletons had a significantly lower neonatal mortality rate than twins that persisted after adjustment for congenital malformations: the first-born twin versus singleton OR 1.71 (1.17–2.51) and second-born versus singleton OR 2.09 (1.43–3.05). Between 28 and 32 weeks, the second-born twin showed a survival advantage over the control singleton. Between 32 and 36 6/7 weeks both twins had a significantly higher survival rate than the corresponding singleton controls. However, after adjustment for congenital malformations, the aforementioned differences between 28 and 36 6/7 weeks disappeared. When at term, twins and singletons had a comparable, though very low, neonatal death rate. These results confirm previous published data. In conclusion, we demonstrated that the neonatal death rate was lower for twins between 32 and 36 weeks (from 28 weeks for the second born twin) when compared to a singleton of the same gestational age. After adjusting for congenital malformations, there was no statistical significant difference.

Does neonatal and infant neurodevelopmental morbidity of multiples and singletons differ?

The mortality and morbidity of twins may differ from that in singletons because of the greater incidence of intrauterine growth restriction, higher rates of prematurity, zygosity and even from the presence of a same age sibling during childhood. Early outcomes appear poorer for twins, but any differences are lost when corrections for gestation and growth restriction are made. Some studies show poorer cognitive outcomes for twins; larger and more recent studies show small but significant differences even when confounders are taken into account. Cerebral palsy rates are considerably higher in twins, especially with the death of a co-twin. Behavioural outcomes are broadly similar in twins and singletons, with growth and gestation being more important determinants than plurality. Psychiatric symptoms again are broadly similar, although there appears to be a reduced risk of suicide in twins.

Clinical issues in the management of late preterm infants

Prematurity is defined as birth before 37 weeks of gestation and is the major determinant of morbidity and mortality in newborns. The gestational ages known as near term or late preterm represent about 75% of preterm births and are the fastest growing subgroups of premature infants. These infants range in gestational age from 34 0/7 to 36 6/7 weeks and are at greater risk of morbidity, such as respiratory complications, temperature instability, hypoglycemia, kernicterus, feeding problems, neonatal intensive care unit admissions, and adverse neurological sequelae when compared with term infants. Long-term neurological and school-age outcomes of late preterm infants are concerns of major public health importance because even a minor increase in the rate of neurological disability and scholastic failure in this group can have a huge impact on the health care and educational systems. There is an urgent need to educate health care providers and parents about the vulnerability of late preterm infants, who are in need of diligent monitoring and care during the initial hospital stay and a comprehensive follow-up plan for post neonatal and long-term evaluations. Clinicians involved in the day-to-day care of late preterm infants, as well as those developing guidelines and recommendations, would benefit from having a clear understanding of the potential differences in risks faced by these infants, compared with their more mature counterparts.

Comparison of short-term outcomes of late preterm singletons and multiple births: an institutional experience

We compare 4 short-term outcomes--namely admission to special care nursery (SCN), length of stay (LOS), age at full feeds (AFF) and respiratory morbidity/need for ventilation--in 1015 late preterm singletons and 366 twins and triplets born at our institution over a 4-year period. Birth weight (BW) and gestational age (GA) rather than plurality of birth determined need for admission to SCN, LOS, AFF, and need for respiratory support. When matched for GA, compared to singletons, twins and triplets needed less admission to SCN and respiratory support at 36 weeks, whereas at 34 weeks, they had longer LOS and took longer to get to full feeds. We conclude that the outcomes of interest are affected by GA and BW rather than plurality.

The risks for very low birth weight infants from multiple pregnancies

Advances in perinatal and neonatal care in recent years have resulted in dramatic improvements in the rate of intact survival of preterm infants. As a result, neonatologists have focused on the new challenge of bringing about similar advances for the tiniest infants who are born at or near the current limits of viability. Although these tiny infants comprise only a small proportion of all births, the ravages of prematurity make them by far the most challenging group of infants who require our attention in the neonatal intensive care unit.

Neuropsychological Outcomes of Preterm Triplets Discordant for Birthweight: A Case Report

Multiple gestation is associated with a higher incidence of preterm birth and preterm birth often results in later neurocognitive and behavioral problems that persist into adulthood. The medical, neurobiological, familial, and socio-environmental factors determinant for an individual are unpredictable. We present neuropsychological data for fraternal triplets discordant for birthweight whose school-age outcome was inconsistent with the low birthweight literature and for whom neurobiological variables appeared especially pertinent. Preterm infants may achieve optimal outcomes, although etiological factors leading to such outcomes may depend heavily on care center variables that limit or avoid intracerebral and other medical complications of prematurity.

The genetics of bronchopulmonary dysplasia

Over the last 15 years, neonatal morbidity and mortality has changed little for very low birth weight babies despite significant technological and therapeutic advances. Bronchopulmonary dysplasia (BPD) continues to be a major problem despite antenatal steroid use, surfactant replacement therapy, gentle noninvasive ventilation techniques, permissive hypercarbia, and judicious use of oxygen. Current evidence supports multiple contributing factors. Prematurity is the cardinal factor; others include pulmonary baro/volutrauma, hyperoxia, and inflammation. BPD is an end product of pulmonary inflammatory response and lung repair with impaired alveolarization and vascularization in response to lung injury. These sequences involve multiple morphoregulatory molecules, which have a range of activities largely determined by genetic variability. A clearer understanding of genetic susceptibility for BPD has recently emerged. Twin studies have shown that the BPD status of one twin, even after correcting for contributing factors, is a highly significant predictor of BPD in the second twin. After controlling for covariates, genetic factors account for 53% (P = 0.004, 95% CI = 16%-89%) of the variance in liability for BPD. Incremental improvements will likely depend on identification of these genetic components for targeting specific therapies.

Multiple gestations and late preterm (near-term) deliveries

Multiple gestations present unique challenges to the modern obstetrician. Many twin and high-order multiple pregnancies are delivered between 34 and 37 weeks' gestation either secondary to preterm labor or obstetrical complications necessitating intervention. Recognizing the increasing prevalence of multiple gestations and the impact of late preterm deliveries in modern practice, this review analyzes the impact of multiple pregnancies on perinatal outcomes, reviews the strategies to prevent preterm labor, and summarizes potential indications for late preterm delivery. In this paper, "late preterm" has been used instead of "near-term," as the former was considered more appropriate to reflect this subgroup of preterm infants in a workshop on this topic held in July 2005, organized by the National Institute of Child Health and Human Development.

Orthopaedic implications of multiple gestation pregnancy with triplets

Intrauterine crowding has been implicated as a risk factor in several orthopaedic conditions, such as developmental dysplasia of the hip (DDH), metatarsus adductus, and torticollis. The goal of this study was to see whether orthopaedic conditions associated with intrauterine crowding were more frequent in multiple gestation pregnancies, specifically in triplets. The authors reviewed their experience over a 10-year period with 261 children who were products of triplet pregnancies. They surveyed 13 orthopaedic conditions and found only one condition, torticollis, that had a greater incidence than that reported in single gestation pregnancies. A 0% incidence of DDH was found in these patients. Routine ultrasound screening cannot be recommended in these patients based on these results.

Increased incidence of necrotizing enterocolitis in premature infants born to HIV-positive mothers

OBJECTIVE

To examine if being born to an HIV-positive mother may increase the risk of necrotizing enterocolitis in premature infants.

DESIGN

Case-control study.

SETTING

Neonatal unit of a level 3 perinatal centre.

METHODS

: Over a period of 8.5 years, all cases of necrotizing enterocolitis occurring in premature infants admitted to the neonatal unit were identified. For each case, two controls were retrospectively chosen that matched for postmenstrual age at birth, intrauterine growth and year of birth. Perinatal characteristics were studied in all infants.

MAIN RESULTS

There were 79 cases of necrotizing enterocolitis, which were compared with 158 controls. Using multivariate analysis, multiple pregnancy [odds ratio (OR), 2.29; 95% confidence interval (CI), 1.23-4.25; P = 0.009], abnormal umbilical artery velocity (OR, 2.21; 95% CI, 1.08-4.54; P = 0.030), abnormal fetal heart rate (OR, 2.14; 95% CI, 1.05-4.36; P = 0.036) and HIV-positive mother (OR, 6.63; 95% CI, 1.26-34.8; P = 0.025) were significantly more frequent in fetuses who subsequently developed necrotizing enterocolitis.

CONCLUSIONS

This preliminary report suggests an association, not previously reported, between maternal HIV-positive status and an increased risk of necrotizing enterocolitis in premature infants. Despite the limitations of this study, we suggest that premature newborn infants of HIV-positive mothers should be monitored very carefully for a possible increased risk of necrotizing enterocolitis.

[Risk factors for mortality in very low birth weight infants with respiratory distress syndrome]

INTRODUCTION

In the last few years the life expectancy of very low birth weight (VLBW) infants has improved. When these patients have respiratory distress syndrome, it is difficult to know with any certainty which factors have the greatest influence on mortality. The aim of this study was to determine which variables, among a series, have the greatest influence on mortality from a multivariate perspective.

PATIENTS AND METHODS

A sample of 209 VLBW infants born over a long period (15 years and 7 months) was studied. The following variables were analyzed: date of birth, degree of respiratory distress syndrome, sex, birth weight, weeks of gestation, born within or elsewhere, prenatal corticoid administration, type of gestation, type of delivery, amniorrhexis time, Apgar test at 1 and 5 minutes, surfactant administration, hours of life at which the first dose of surfactant was administered, and early sepsis. A multiple logistic regression analysis was developed using Hosmer-Lemeshow methodology.

RESULTS

The following variables were identified as significant: birth weight, Apgar test at 5 minutes, prenatal corticoids, degree of respiratory distress syndrome, and surfactant administration. The remaining variables were less important in the multivariate analysis.

CONCLUSIONS

Higher birth weight and Apgar score at 5 minutes, prenatal corticoid and surfactant administration, and a lower degree of respiratory distress syndrome reduce mortality. The logistic regression model used quantifies how these factors behave and allows the probability of mortality in VLBW infants with respiratory distress syndrome to be estimated.

Long-term outcomes in multiple gestations

Children born from a multiple gestation are at increased risk for cerebral palsy, learning disability, and language and neurobehavioral deficits. With the increased incidence of multiple pregnancies and use of assisted reproductive technology (ART), these issues are more commonly affecting parents. Long-term outcomes are a critical part of preconceptual and early pregnancy counseling for parents faced with a multiple gestation or considering ART, and the provider should be well versed on issues surrounding zygosity, gestational age, higher-order multiples, and the effects of options such as multifetal pregnancy reduction.

Neonatal morbidity of very low birth weight infants from multiple pregnancies

The epidemic of multiple births has translated into a marked rise in very low birth weight infants, who are at risk for major neonatal morbidity and mortality. Gestational age-adjusted comparisons of outcome between singletons and multiples have shown conflicting results. Comparisons that corrected for relevant confounding variables show that twins and singletons have similar risks for early morbidity and mortality. Very low birth weight triplets may have increased risk for neonatal mortality, however. Second-born very low birth weight twins seem to be at risk for increased respiratory morbidity, even in the era of routine antenatal corticosteroids and postnatal surfactant therapy.

The EPIBEL study: outcomes to discharge from hospital for extremely preterm infants in Belgium

OBJECTIVE

To determine mortality and morbidity at discharge from the hospital of a large population-based cohort of infants who were born at <or=26 weeks' gestation.

METHODS

Perinatal data were collected on extremely preterm infants who were alive at the onset of labor and born between January 1, 1999, and December 31, 2000, in all 19 Belgian perinatal centers.

RESULTS

A total of 525 infants were recorded. Life-supporting care was provided to 322 liveborn infants, 303 of whom were admitted for intensive care. The overall survival rate of liveborn infants was 54%. Of the infants who were alive at the age of 7 days, 82% survived to discharge. Vaginal delivery, shorter gestation, air leak, longer ventilator dependence, and higher initial oxygen need all were independently associated with death; gender, plurality, and surfactant therapy were not. Among the 175 survivors, 63% had 1 or more of the 3 major adverse outcome variables at the time of discharge (serious neuromorbidity, chronic lung disease at 36 weeks' postmenstrual age, or treated retinopathy of prematurity). The chance of survival free from serious neonatal morbidity at the time of hospital discharge was <15% (21 of 158) for the admitted infants with a gestation <26 weeks.

CONCLUSIONS

If for the time being prolongation of pregnancy is unsuccessful, then outcome perspectives should be discussed and treatment options including nonintervention explicitly be made available to parents of infants of <26 weeks' gestation within the limits of medical feasibility and appropriateness.

Twins and triplets: the effect of plurality and growth on neonatal outcome compared with singleton infants

OBJECTIVE

Information on outcome by gestational age from large numbers of twins and triplets is limited and is important for counseling and decision-making in obstetric practice. We reviewed one of the largest available neonatal databases to describe mortality and morbidity rates and growth in newborn infants from multiple gestations and compared these data with data for singletons.

STUDY DESIGN

Data from a large prospectively recorded neonatal database that incorporated neonatal records from January 1997 to July 2002 were reviewed. We evaluated birth weight and neonatal mortality and morbidity rates that affected long-term outcome for each week of gestational age from 23 to 35 weeks of gestation for all nonanomolous inborn twins and triplets who were admitted to the neonatal intensive care unit and compared these data to all singletons who met similar criteria during the same time period.

RESULTS

There were 12,302 twin and 2155 triplet births that met the entry criteria. The data for these newborn infants were compared with 36,931 singletons. Average birth weights at each gestational week were similar for all gestational ages until 29 weeks of gestation for triplets and 32 weeks of gestation for twins. After these gestational ages, the entire difference between twins and singletons was due to the weight of the smaller twin; the larger twins' mean weights were similar to singletons at all weeks that were studied. Birth order at each week also did not affect neonatal mortality rates, even when corrected for route of delivery and antenatal steroids. Neonatal morbidities associated with adverse long-term outcomes (intraventricular hemorrhage, retinopathy of prematurity, necrotizing enterocolitis) were also not different between multiple infants and singletons. Intrauterine growth restriction (IUGR) was associated with increased mortality rates at all gestational ages, but in the absences of IUGR, discordance was not.

CONCLUSION

Data on a large number of twins and triplets provide reassurance that neonatal outcome at all viable premature weeks of gestation are similar to singletons. Intrauterine growth restriction and prematurity are therefore the principal issues that drive neonatal mortality and morbidity rates in multiple gestations. These data are important for obstetric decision-making and patient counseling.

Survival of very preterm infants: Epipage, a population based cohort study

OBJECTIVE

To evaluate the outcome for all infants born before 33 weeks gestation until discharge from hospital.

DESIGN

A prospective observational population based study.

SETTING

Nine regions of France in 1997.

PATIENTS

All births or late terminations of pregnancy for fetal or maternal reasons between 22 and 32 weeks gestation.

MAIN OUTCOME MEASURE

Life status: stillbirth, live birth, death in delivery room, death in intensive care, decision to limit intensive care, survival to discharge.

RESULTS

A total of 722 late terminations, 772 stillbirths, and 2901 live births were recorded. The incidence of very preterm births was 1.3 per 100 live births and stillbirths. The survival rate for births between 22 and 32 weeks was 67% of all births (including stillbirths), 85% of live births, and 89% of infants admitted to neonatal intensive care units. Survival increased with gestational age: 31% of all infants born alive at 24 weeks survived to discharge, 78% at 28 weeks, and 97% at 32 weeks. Survival among live births was lower for small for gestational age infants, multiple births, and boys. Overall, 50% of deaths after birth followed decisions to withhold or withdraw intensive care: 66% of deaths in the delivery room, decreasing with increasing gestational age; 44% of deaths in the neonatal intensive care unit, with little variation with gestational age.

CONCLUSION

Among very preterm babies, chances of survival varies greatly according to the length of gestation. At all gestational ages, a large proportion of deaths are associated with a decision to limit intensive care.

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.

A comparison of the neonatal morbidity of second twins to that of a low-risk population

OBJECTIVE

To assess the neonatal morbidity of second twins.

STUDY DESIGN

Cohort study in a department of perinatalogy. The neonatal morbidity of second twins was compared to that of a low-risk population: singletons in the cephalic presentation delivered vaginally.

RESULTS

Five hundred fifty-nine second twins and 18,061 vaginally delivered singletons in the cephalic presentation were studied. Of 452 (81%) second twins delivered vaginally, 310 (69%) were extracted using obstetrical maneuvers: internal version and breech extraction, breech extraction alone, or assisted breech delivery if the breech was already engaged. Before 33 weeks of gestation, there was no significant difference between the neonatal morbidity of the vaginally delivered second twins and the vaginally delivered singletons in the cephalic presentation. After 33 weeks of gestation, only the 1-min Apgar score <7 and the rate of intubation at birth were significantly higher in the second twins. Whatever the gestational age, there was no significant difference between the neonatal morbidity of the vaginally delivered second twins and that of the second twins born by cesarean section before labor. At comparable gestational ages, there was no significant difference between the death rate of the vaginally delivered second twins and that in the reference population.

CONCLUSION

The neonatal morbidity of second twins was comparable to that of a low-risk population. Immediate management of the vaginally delivered second twins was, however, more intensive than that of vaginally delivered singletons in the cephalic presentation. It, therefore, requires appropriate equipment in a suitable obstetric-pediatric setting.

Neonatal outcome of triplet versus twin and singleton pregnancies: a matched case control study

OBJECTIVE

To determine the neonatal outcome of triplet gestations versus that of singletons and twins matched for gestational age.

STUDY DESIGN

All live born triplet gestations delivered between 1 April 1993 and 31 March 2000 were compared to an age matched control group consisting of live born twins and singletons. The neonatal outcome of 116 sets of triplets was compared to that of 116 sets of twins and 116 singletons.

RESULTS

During a 7-year period 116 sets of triplet pregnancies were reviewed. Of 116 sets of live born triplets (348 newborns), 70.67% triplets were born between 33- and 36-week gestation, 28.44% between 28 and 32 weeks and 0.86% less than 28 weeks. Triplets were smaller in weight than singletons but not twins. Apgar score, use of prenatal steroid and sex ratio were similar in the three groups. Incidence of respiratory distress syndrome (RDS), use of surfactant, infants requiring intubation, pneumothorax, patent ductus arteriosus, sepsis, intraventricular hemorrhage, periventricular leucomalacia, retinopathy of prematurity, necrotizing enterocolitis, gastroesophageal reflux and jaundice requiring phototherapy were not statistically different among the three groups. Incidence of major and minor congenital anomalies, percent neonatal intensive care unit (NICU) admissions, and mean duration of NICU stay were also similar. There was no influence of birth order on neonatal outcome of triplet pregnancy and outcome did not significantly change over 7 years of the study period.

CONCLUSIONS

Triplets have a similar outcome to twins and singletons when matched for gestational age. Since outcome is dependent on gestational age, the closer the gestational age is to term the better is the outcome.

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.

Neonatal and long-term outcomes of very low birth weight infants from single and multiple pregnancies

The revolution in artificial reproductive technologies has resulted in a dramatic rise in the incidence of multiple pregnancies. Many of these infants are born prematurely, often extremely so. Consequently, perinatal morbidity and mortality are highly correlated with plurality. The primary mechanism for this increased risk is prematurity. Studies of the relationship between plurality and outcome are frequently hampered by major differences in case mix between singletons, twins and high multiples. For example, high multiples tend to receive earlier prenatal care, receive more antenatal steroids, are more often delivered by Caesarean section and more often suffer from respiratory distress syndrome. However, recent studies that appropriately account for relevant confounding variables have suggested that very low birth weight infants from high multiple pregnancies are at excess risk for mortality when compared with twins and singletons. This article reviews the current available evidence.

Retinopathy of prematurity: causation

The incidence of ROP is birth weight dependent and restricting therapeutic oxygen levels has dramatically reduced the incidence of ROP in infants of birth weight >1000 g. However, the incidence of ROP has remained high in very low birth weight (VLBW) infants and this appears to be related to these babies being more ill. Several risk factors have been identified in this group, however oxygen variability, rather than high levels, has been correlated with severity of disease in recent clinical and animal studies. Difficulties in defining 'normal' oxygen in this group has meant the optimal range of oxygen therapy has not yet been defined. Clinical studies are now underway using even lower oxygen therapy ranges. The impact this may have on ROP, neurological and respiratory outcomes will require further study.

Respiratory distress syndrome and birth order in premature twins

OBJECTIVE

To determine the effect of birth order on respiratory distress syndrome (RDS) in the outcome of twins in a large premature population managed in a modern neonatal intensive care unit.

METHODS

An historical cohort study design was used to analyse the neonatal outcomes of 301 premature liveborn twin sibling pairs of between 23 and 31 weeks gestation from the Australia and New Zealand Neonatal Network 1995 database.

RESULTS

Among the 56 twin sibling pairs who were discordant for RDS, the second twin was affected in 41 cases (odds ratio (OR) 2.7, 95% confidence interval (CI) 1.5 to 5.3). The excess risk of RDS in the second twin increased with gestation and was statistically significant for twins above 29 weeks gestation (OR 4.4, 95% CI 1.6 to 15).

CONCLUSIONS

There is a significant increased risk of RDS associated with being the second born of premature twins, which appears to depend on gestation.

A comparison of recent trends in infant mortality among twins and singletons

Overall infant mortality rates have steadily declined in recent years. The goal of this study was to examine whether recent declines in infant mortality were similar for twins and singletons, and to assess the impact of differing birthweight distributions on these relationships. Linked birth and infant death records for 1985-86 and 1995-96 were used to calculate infant mortality rates for twins and singletons for the two time periods. Bootstrap simulations were used to estimate rates of decrease between the two time periods and to determine whether these rates differed between twins and singletons. Between 1985-86 and 1995-96, infant mortality among twins declined significantly faster than among singletons (36% vs. 29%, P < 0.05). This difference was true for both black and white infants (black: 28% for twins vs. 22% for singletons; white: 38% for twins vs. 31% for singletons). Within birthweight categories, infant mortality declined more rapidly among twins than among singletons, although differences were not always significant. Factors and circumstances that contributed to the infant mortality decline in the United States have benefited twins to a greater extent than singletons.

Retinopathy of prematurity: evaluation of risk factors

OBJECTIVES

The purpose of this study was to determine what risk factors play a role in the development of retinopathy of prematurity (ROP).

STUDY DESIGN

Data were collected on 157 infants born and cared for in one institution between January 1991 and July 1994. Initially we evaluated all children enrolled in the study to determine potential risk factors for the development of ROP. We subsequently compared multiple variables for ROP positive singletons with ROP positive twins to determine ROP risk factors for each group and to determine if one group was more susceptible to a given risk factor.

RESULTS

Of the 157 infants examined, 72 infants (46%) developed ROP. Infants who developed ROP had a lower gestational age, a lower birth weight, a higher number of days on oxygen/ventilator, more days in the intensive care unit (ICU), a greater need for steroids and a higher incidence of sepsis when compared to infants who did not develop ROP. There was no significant difference noted between singleton and twin gestation infants that developed ROP when comparing gestational age, weight, ventilator time or length of ICU stay. Total number of days on oxygen therapy was higher in the singleton group and this difference did reach statistical significance.

CONCLUSIONS

Several risk factors are associated with a higher incidence of ROP. These variables may not be independent risk factors but may be a sign of the increased severity of illness associated with those infants who are born earlier with a lower birth weight. Multiple gestational births do not appear to increase the risk of developing ROP when compared to a similar group of singleton birth infants.

Multiple births and outcome

The rate of multiple-gestation pregnancies has grown exponentially over the last few decades and is responsible for the steady increase in the birth rate of low-birth weight infants. As a group, infants of multiple-gestation pregnancies have higher mortality and morbidity than singleton pregnancies. The increase in adverse outcomes is related directly to the increased risk for preterm delivery and low-birth weight, and not to the multiple gestation itself. Outcomes for multiple-gestation infants appear to be similar whether conceived spontaneously or through artificial reproductive technology. Efforts to reduce the birth rate of low-birth weight infants should target multiple-gestation pregnancies.

Outcomes of children of extremely low birthweight and gestational age in the 1990s

Advances in perinatal care have improved the chances for survival of extremely low birthweight (<800 grams) and gestational age (<26 weeks) infants. A review of the world literature reveals that among regional populations, survival at 23 weeks' gestation ranges from 2 to 35%, at 24 weeks' gestation 17 to 62% and at 25 weeks' gestation 35 to 72%. These wide variations may be accounted for by differences in population descriptors, in the criteria used for starting or withdrawing treatment, in the reported duration of survival and differences in care. Major neonatal morbidity increases with decreasing gestational age and birthweight. At 23 weeks' gestation, chronic lung disease occurs in 57 to 86% of survivors, at 24 weeks in 33 to 89% and at 25 weeks' gestation in 16 to 71% of survivors. The rates of severe cerebral ultrasound abnormality range from 10 to 83% at 23 weeks' gestation, 9 to 64% at 24 weeks and 7 to 22% at 25 weeks' gestation Of 77 survivors at 23 weeks' gestation, 26 (34%) have severe disability (defined as subnormal cognitive function, cerebral palsy, blindness and/or deafness). At 24 weeks' gestation, the rates of severe neurodevelopmental disability range from 22 to 45%, and at 25 weeks' gestation 12 to 35%. When compared with children born prior to the 1990s, the rates of neurodevelopmental disability have, in general, remained unchanged. We conclude that, with current methods of care, the limits of viability have been reached. The continuing toll of major neonatal morbidity and neurodevelopmental handicap are of serious concern.

Antepartum evaluation of monochorionic diamniotic (MD) twins; MD-twin score: a new scoring method for perinatal outcome

OBJECTIVE

Our purpose was to establish a new scoring method to survey monochorionic diamniotic (MD) twins during antepartum periods.

STUDY DESIGN

A retrospective study was performed regarding MD twins delivered between January 1992 and July 1996. Maternal and neonatal records were assessed for the following 5 perinatal variables; birth-weight discordance, amniotic-fluid discordance, hydrops fetalis, umbilical-cord insertion, and fetal-heart-rate monitoring. Each variable was coded as normal or abnormal and then assigned an arbitrary weight of 0 if normal and 1 if abnormal, yielding a range of scores from 0 (all normal) to 5 (all abnormal). The relationships between individual variables and their combinations and the outcome of pregnancy was determined. A poor pregnancy outcome consisted of intrauterine death, neonatal death, or neurological sequelae of at least one twin. The 5-variable combination was termed as the MD-twin score. A chi-square test and logistic regression analysis were used to determine statistical significance.

RESULTS

There were 59 MD pregnancies, of which 13 pregnancies resulted in a poor outcome. The single variable that most likely contributed to a poor outcome was amniotic-fluid discordance. All 35 pregnancies with an MD-twin score of < or = 2 had a good outcome. There were 14 pregnancies with a score of 3, and 21% of them had a poor outcome. All of the pregnancies with a score of > or = 4 had a poor outcome. When we chose the MD-twin score of 3 as the critical point for a poor outcome, the likelihood ratio statistics became the highest of any single variable or any combination of variables.

CONCLUSION

The MD-twin score predicted poor outcomes better than did any single variable or combination of variables.

Impact of gestational age at delivery of the economics of triplet pregnancy

OBJECTIVE

To establish the charges associated with triplet pregnancies managed at a single tertiary center, over a 5-year time period, and to evaluate the impact of prematurity on these charges.

METHODS

All triplet pregnancies that reached at least 20 weeks gestation and received prenatal and neonatal care at our center from 1992 to 1996 were included. Charges for these mothers and neonates were extracted from two separate hospital billing computer systems, encompassing all inpatient, outpatient, technical, and professional charges. Linear regression was used to evaluate the relationship between gestational age at delivery and total charges.

RESULTS

Fifty-five triplet pregnancies were included, resulting in the admission of 149 liveborn neonates. The median gestational age at delivery was 32.1 weeks. The mean charges per triplet mother were: $6,899 (professional), $3,959 (hospital outpatient), and $32,686 (hospital inpatient). The mean charges per neonatal sibling set were: $20,107 (professional) and $124,163 (hospital inpatient). The mean charges per complete triplet pregnancy was $187,814 (maternal plus neonatal). There was a significant inverse relationship between gestational age at delivery and total charges per triplet family, with a decrease of $16,584 for each additional gestational week reached (P = 0.006).

CONCLUSIONS

Triplet pregnancy charges averaged almost $190,000 each, which does not include charges associated with assisted reproductive technologies. These charges are almost all related to the expense of prolonged neonatal intensive care, and are significantly related to the gestational age at delivery. Efforts at containing these costs should focus on reducing the incidence of multiple gestation and preventing prematurity.

Elective cytogenetic amniocentesis in the third trimester for pregnancies with high risk factors

The aim of the present study was to report the findings in 14 women with extremely high risk ('precious') pregnancies, 5 of whom had twins, who underwent elective third-trimester cytogenetic amniocentesis. There were no procedure-related complications, and all newborns weighed more than 2000 g and showed normal development. This practice is accepted under Israeli law and our institutional policy. This preliminary work does not attempt to answer the moral and ethical questions surrounding the use of third (versus second) trimester amniocentesis in either 'precious' or normal pregnancies. We do show, however, that the procedure is safe and may constitute a good alternative for patients who are unwilling to accept the risks of early fetal karyotyping.

Improving pregnancy outcome in twin gestations with one malformed fetus by postponing selective feticide in the third trimester

OBJECTIVE

To examine the course of pregnancy and fetal outcome in patients with twin gestations in which one abnormal fetus underwent selective feticide in the third trimester of pregnancy.

DESIGN

A study of 23 consecutive late selective feticide procedures.

SETTING

Department of Obstetrics and Gynecology, Rabin Medical Center, Israel.

PATIENT(S)

Twenty-three patients with twin pregnancies with one malformed fetus.

INTERVENTION(S)

Selective feticide with intracardiac injection of KCl was performed at 28-33 weeks of gestation after the diagnosis of fetal genetic (56.5%) or structural (43.5%) malformations made in the second trimester (18-24 weeks). All procedures were performed at the patient's request and on approval of a committee for fetal termination late in pregnancy. Betamethasone treatment was initiated to enhance lung maturity 3 weeks before selective feticide. All patients were placed on complete bed rest until 35 weeks' gestation.

MAIN OUTCOME MEASURE(S)

Early and late complications related to the procedure; outcome of pregnancy and fetal survival.

RESULT(S)

All 23 twin pregnancies had an uneventful course after selective feticide performed at 28-33 weeks. All birth weights were > 2,000 g (mean +/- SD, 2,628 +/- 646 g), indicating an excellent chance of survival.

CONCLUSION(S)

Our results suggest that late selective feticide in twin gestations is safe and efficient and results in a favorable outcome for the surviving fetus. This procedure should be performed at 28-30 weeks after treatment for enhancement of lung maturity.

Recent advances in the therapeutic management of preterm labour

Preterm labour and delivery pose an increasing problem to the obstetrician. Improvements in tocolysis with the recent introduction of new therapeutic targeting strategies, and a reappraisal of the safety and relative efficacy of some older compounds, have led to a tendency away from prescribing beta-sympathomimetic agents. Infection prophylaxis and promotion of fetal lung maturity are deemed advantageous, but treatment protocols have not been clarified. This review examines the important publications of the past year in these areas.

Infertility: from a personal to a public health problem

The inability to conceive a child is most often viewed as a private matter, but public health perspectives and skills can contribute greatly to our knowledge about infertility, and the development of effective and rational public policy for prevention, access to health care, and regulation of new technologies. We offer a primer of public health aspects of infertility in an effort to encourage the broad spectrum of public health professionals to become more knowledgeable about these topics and join in the national debate about preventive strategies, cost-benefit assessment, resource allocation, and ethics.

Outcomes of children of extremely low birthweight and gestational age in the 1990's

Advances in perinatal care have improved the chances for survival of extremely low birthweight (< 800 g) and gestational age (< 26 weeks) infants. A review of the world literature and our own experience reveals that at 23 weeks gestation survival ranges from 2% to 35%. At 24 weeks gestation the range is 17% to 58%, and at 25 weeks gestation 35% to 85%. Differences in population descriptors, in the initiation and withdrawal of treatment and the duration of survival considered may account for the wide variations in the reported ranges of survival. Major neonatal morbidity increases with decreasing gestational age and birthweight. The rates of severe cerebral ultrasound abnormality range at 23 weeks gestation from 10% to 83%, at 24 weeks from 17% to 64% and at 25 weeks gestation from 10% to 22%. At 23 weeks gestation, chronic lung disease occurs in 57% to 70% of survivors, at 24 weeks in 33% to 89%, and at 25 weeks gestation in 16% to 71% of survivors. When compared to children born prior to the 1990's, the rates of neurodevelopmental disability have, in general, remained unchanged. Of 30 survivors reported at 23 weeks gestation nine (30%) are severely disabled. At 24 weeks gestation the rates of severe neurodevelopmental disability (including subnormal cognitive function, cerebral palsy, blindness and deafness) range from 17% to 45%, and at 25 weeks gestation 12% to 35% are similarly affected. In Cleveland, Ohio, we compared the outcomes of 114 children with birthweight 500-749 g born 1990-1992 to 112 infants born 1993-1995. Twenty month survival was similar (43% vs 38%). The use of antenatal and postnatal steroids increased (10% vs 54% and 43% vs 84%, respectively, P< 0.001), however the rates of chronic lung disease increased from 41% to 63% (P = 0.06). There was a significant increase in the rate of subnormal cognitive function at 20 months corrected age (20% vs 48%, P < 0.02) and a trend to an increase in the rate of cerebral palsy (10% vs 16%) and neurodevelopmental impairment. We conclude that, with current methods of care, the limits of viability have been reached. The continuing toll of major neonatal morbidity and neurodevelopmental handicap are of serious concern.