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* Departments of Pediatrics
Medical Statistics, Leiden University Medical Center, Leiden, Netherlands
Ministry of Health and Science, The Hague, Netherlands
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ABSTRACT |
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 TOP ABSTRACT METHODSRESULTSDISCUSSIONREFERENCES |
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Methods. The Leiden Follow-Up Project on Prematurity (LFUPP-1996/97), a regional, prospective study, includes all infants who were born alive after a GA <32 weeks in 1996 and 1997 in the Dutch health regions Leiden, The Hague, and Delft. The Project On Preterm and Small for Gestational Age Infants (POPS-1983), a national, prospective study from the presurfactant era, includes all liveborn infants <32 weeks' GA and/or <1500 g from 1983 (n = 1338). For comparison, infants from the POPS-1983 cohort with a GA <32 weeks from the same Dutch health regions were selected (n = 102).
Results. The absolute number of preterm births in the study region increased by 30%: 102 in 1983 to on average of 133 in 1996–1997. Centralization of perinatal care improved: the percentage of extrauterinely transported infants decreased from 61% in 1983 to 35% in 1996–1997. A total of 182 (73%) of the LFUPP-1996/97 infants were treated antenatally with glucocorticosteroids compared with 6 (6%) of the POPS-1983 infants. A total of 112 (42%) of the LFUPP-1996/97 infants received surfactant. In-hospital mortality decreased from 30% in the 1980s to 11% in the 1990s. Mortality of the extremely preterm infants (<27 weeks) decreased from 76% to 33%. The incidence of respiratory distress syndrome remained the same: 
60% in both groups. Mortality from respiratory distress syndrome, however, decreased from 29% to 8%. The incidence of bronchopulmonary dysplasia increased from 6% to 19%. For the surviving infants, the average length of stay in the hospital and the mean number of NICU days stayed approximately the same (67 days total admission time and 44 NICU days in both groups); including the infants who died, the mean NICU admission time increased from 27 days in the 1980s to 41 days in the 1990s. Equal percentages of adverse outcome (dead or an abnormal general condition) at the moment of discharge from hospital were found (±40% in both groups).
Conclusions. An increase in the absolute number of very preterm births in this study region was found, leading to a greater burden on the regional NICUs. Improvements in peri- and neonatal care have led to an increased survival of especially extremely preterm infants. However, increased survival has resulted in more morbidity, mainly bronchopulmonary dysplasia, at the moment of discharge from the hospital.
Key Words: changes in peri- and neonatal care • time trend
Abbreviations: LFUPP, Leiden Follow-up Project on Prematurity • POPS, Project on Preterm and Small for Gestational Age Infants • GA, gestational age • SGA, small for gestational age • RDS, respiratory distress syndrome • BPD, bronchopulmonary dysplasia • PROM, prolonged rupture of membranes • IVF, in vitro fertilization • IVH, intraventricular hemorrhage • OR, odds ratio
Perinatology has changed dramatically over the years. Advances in technology such as high-frequency oscillation and new ways of treatment such as the administration of glucocorticosteroids antenatally and surfactant therapy have resulted in an increasing number of surviving infants. The limit of viability continues to be challenged.
Most studies that have compared the outcome of infants who were born in the presurfactant era with that of infants who were born after the introduction of surfactant are hospital based. These hospitals are most often tertiary care–level centers, which leads to a selection bias as the older or more mature preterm infants who do not need this level of intensive care are not included. In this study, we therefore compare a regional-based follow-up study—the Leiden Follow-up Project on Prematurity 1996–1997 (LFUPP-1996/97)—with a national follow-up study from the 1980s: the Project on Preterm and Small for Gestational Age Infants 1983 (POPS-1983).1–3 Changes in neonatal mortality and morbidity are described as well as changes in perinatal and neonatal management.
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METHODS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONREFERENCES |
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The 3 Dutch health regions used in the study are situated in the Dutch province Zuid-Holland. In the years 1996–1997, this province had 3.4 million inhabitants of a total of 15.5 million people living in the entire Netherlands. With 21% of the total Dutch population living in this province, it is a reasonably densely populated region. Demographic data of Netherlands and the studied region in 1983 and 1996–1997 as well as socioeconomic data are listed in Table 1.
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The LFUPP-1996/97 ultimately included 266 infants, constituting 92% of eligible infants who were born in 1996 and 1997 (97% of eligible infants from 1996 and 88% of eligible infants from 1997). Of these 266 infants, 163 (62%) were born in tertiary-level centers (centers with a NICU), 122 (75%) of those 163 were born in the Leiden University Medical Center. Seventy-one (27%) of 266 were born in regional hospitals in The Hague and immediately after birth transported to the NICU of the Juliana Children's Hospital in The Hague. This hospital did not have a maternity ward, so all children who were born in The Hague and had a need for intensive care had to be transported to this hospital.
The Leiden University Medical Center and the Juliana Children's Hospital have the same clinical neonatal care; a total of 193 (73%) of the infants were admitted to either one of these hospitals. The other hospitals that contributed to this study had the same clinical protocol for resuscitation, with the exception that other NICU hospitals did not resuscitate infants who were <25 weeks' GA. In the study region, full resuscitation in the delivery room was started from a GA of 24+0 weeks.
The POPS was started in 1983. This national, prospective study from the presurfactant era includes all infants who were born alive after a GA <32 weeks and/or had a birthweight <1500 g in 1983 in Netherlands. At that time, no data were routinely available on incidence of preterm or small for gestational age (SGA) birth and morbidity or mortality by GA or birth weight. Because collecting data on all high-risk newborns in Netherlands would have involved 10 000 or more infants per year, we decided to collect data on the smallest and least mature infants with the highest risk of mortality and morbidity.
The POPS-1983 included 1338 infants, constituting 94% of eligible infants who were born in 1983. A total of 102 of these infants had a GA <32 weeks and were born in the LFUPP-1996/97 health regions. Thirty-three (32%) of these infants were born in centers with a NICU; of those, 24 (73%) were born in the Leiden University Medical Center. Forty-one (33%) infants were born in regional hospitals in The Hague and immediately after birth transported to the NICU of the Juliana Children's Hospital in The Hague. As in the 1990s, this hospital did not have a maternity ward. In the 1980s, neonatal care in the Leiden University Medical Center and the Juliana Children's Hospital were equal; full resuscitation was also started from a GA of 24+0 weeks. GA was generally well known in Netherlands in the 1980s and certainly in the 1990s because of good, standardized antenatal care with early (GA 12 weeks) ultrasound assessments.
For comparison of the 2 cohorts, only the infants of the POPS-1983 cohort who were <32 weeks' GA and from the same health regions (selection by postal code) as the infants from the LFUPP cohort were included in the analyses. We chose not to include the SGA infants who were >32 weeks' GA as these infants are more mature and therefore not comparable to very preterm infants.
In both studies, perinatal factors were collected on precoded forms. Data collected included preexisting diseases of the mother, obstetric history, and neonatal data.
Causes of death were multiple in many infants (eg, both pulmonary and infectious problems). The main cause of death as judged by the pediatrician-neonatologist was used to create Table 2 concerning causes of death.
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Bronchopulmonary dysplasia (BPD) was defined according to Shennan et al4 in the LFUPP-1996/97 and according to Bancalari et al5 in the POPS-1983. According to Shennan, an infant experiences BPD when it is still oxygen dependent at 36 weeks' postmenstrual age. The Bancalari definition includes mechanical ventilation for at least 3 days in the first week after birth, clinical signs of chronic respiratory disease, oxygen dependency, and persistent radiographic changes at 28 days post partum.
The variable "condition at discharge from hospital" was dichotomous in the LFUPP-1996/97; when any abnormality existed, this variable was encoded as abnormal. Abnormalities could include neurologic disorders (on clinical examination), pulmonary problems (BPD), cardiac disorders, feeding problems (eg, tube feeding), visual problems (retinopathy of prematurity), or hearing disorders. In the POPS-1983, this variable could also be encoded dubious; for the comparison, dubious cases were considered abnormal.
Both studies were approved by the Ethics Committee of The Leiden University Medical Center. Parental informed consent was obtained.
Statistical Analysis
SPSS 10.0 for Windows was used for statistical analyses. The 
2 test was used to compare categorical variables, Fisher exact test was applied where appropriate. Student's t test was used for comparison of continuous variables. The Kaplan-Meier method was used for a survival analysis of the first 28 days post partum. P < .05 was considered significant.
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RESULTS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONREFERENCES |
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Obstetric History
Socioeconomic status and preexisting diseases of the mother, diseases, intoxications, and medication during pregnancy are shown in Table 3. Socioeconomic status of the mother (as determined by level of education) was high in 29%, average in 50%, and low in 21% of the mothers in the 1990s. The corresponding percentages in the 1980s are 33%, 30%, and 37% (P = .005). In both groups, however, the number of missings for this variable was considerable: 21% in the LFUPP-1996/97 group and 30% in the POPS-1983 group.
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Use of antibiotics increased almost 3-fold: 29% of the mothers in the LFUPP-1996/97 group received antibiotics during their pregnancy as opposed to 10% in the POPS-1983 group (P < .001; Table 3). The percentage of mothers who had prolonged rupture of membranes (PROM) and received antibiotics was higher in the LFUPP-1996/97 group: 48% (45 of 93) versus 9% (4 of 44; P < .001). Dividing the PROM into <24 hours and 
24 hours, the percentage of mothers who were treated with antibiotics was still significantly higher in the LFUPP-1996/97 cohort in both groups: 33% (6 of 18) versus 4% (1 of 23) when PROM was <24 hours (P = .01) and 52% (39 of 75) versus 14% (3 of 21; P < .001) when PROM was 24 hours. No significant difference was found in frequency of treatment with antibiotics in women without PROM: 18% (29 of 165) in the LFUPP-1996/97 group and 10% (6 of 58) in the POPS-1983 group (P = .2).
For the POPS-1983 group, no data about pregnancy induction (in casu hormone treatment since in vitro fertilization [IVF]) was just coming about in the early 1980s) were available. In the LFUPP-1996/97 group, pregnancy was induced in 21 mothers, leading to a total of 36 (14%) of 265 births: hormone treatment in 6 mothers (12 infants [33%]), IVF in 13 (22 infants [61%]), and intracytoplasmic sperm injection in 2 mothers (2 infants [6%]).
Delivery
Data concerning the delivery are listed in Table 4. Use of tocolytics and antenatal administration of corticosteroids occurred significantly more often in the 1990s cohort. Mean maternal age at birth increased by almost 4 years, from 26.8 in 1983 to 30.5 in 1996–1997.
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The duration of rupture of membranes at delivery differed significantly between the groups. The majority of membrane ruptures was of short duration (<24 hours) in the POPS-1983 group (23 of 44 [52%]) and of longer duration (1–7 days) in the LFUPP-1996/97 group (74 of 93 [80%]).
Mean GA (29 weeks) and the percentage of immature infants (<27 weeks; 17%) did not differ between the groups (Table 4). GA was certain in 251 (95%) of 263 LFUPP-1996/97 infants, dubious in 8 (3%), and uncertain in 4 (2%). In the POPS-1983 cohort, the corresponding numbers were certain in 71 (70%) of 102, dubious in 19 (19%), and uncertain in 11 (11%; Table 4).
Birth Characteristics
A comparison of birth characteristics and neonatal morbidity of the infants from the POPS-1983 and LFUPP-1996/97 groups is presented in Table 5. Mean GA; mean birth weight; and percentages of infants who were born SGA (birth weight <10th percentile),6 were of male gender, had congenital malformations, and were of white race did not differ between the 2 groups.
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The percentage of infants who were born in hospitals with a NICU increased from 32% to 62%; the percentage of infants who were transported after birth to centers with a NICU decreased from 61% in the 1980s to 35% in the 1990s (P < .001). In both groups, the majority of transported infants were born in The Hague; almost all infants in this region had to be transported after birth to the Juliana Children's Hospital. In the POPS-1983 group, 41 (66%) of 62 transported infants were transported to this hospital; in the LFUPP-1996/97 group, 71 (76%) of 93 infants were transported to this hospital. In the POPS-1983 group, 7 (10%) of the 69 infants who were born in a center without a NICU did not have to be transported after birth; the corresponding number in the LFUPP-1996/97 group was 10 (10%) of 103 infants.
In-Hospital Mortality
In-hospital mortality was 11% (29 of 266) in the LFUPP-1996/97 group and 30% (31 of 102) in the POPS-1983 group (P < .001). For the immature infants (GA <27 weeks), in-hospital mortality decreased from 76% (13 of 17) to 33% (15 of 46). In-hospital mortality is shown in Fig 1 according to GA. In the 1990s, mortality was lower in all GA categories. A survival analysis (Kaplan-Meier curve) for the first 28 days is shown in Fig 2 for both the immature and the nonimmature infants. In the 1990s, the nonsurviving infants died after an average of 12.7 days; in the 1980s, the corresponding number was 5.9 (P = .3; Table 2).
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27 weeks' GA) as well, the percentage of deaths within 24 hours was higher in the POPS-1983 group, although not significant: 61% (11 of 18) versus 36% (5 of 14; P = .2). Late neonatal death (between 7 and 28 days after birth) was 38% (11 of 29) in the LFUPP-1996/97 group; none of the POPS-1983 infants died in this period. In both groups, 2 infants died after 28 days post partum. Treatment was withdrawn because it was considered to be medically futile in 52% of the LFUPP-1996/97 deaths and in 45% of the POPS-1983 deaths (P = .6). Withdrawal of treatment occurred in equal percentages in the immature (<27 weeks' GA) and more mature infants and in infants who died within or after 24 hours in both groups.
Pulmonary problems seemed to be the most important cause of death; in both groups, 50% of the infants who died in the neonatal period died mainly of RDS (13 of 29 LFUPP-1996/97 group; 16 of 31 POPS-1983 group; Table 2). Mortality from RDS as a function of the number of infants who had RDS, however, decreased significantly: 29% (16 of 55) of the infants with RDS from the POPS-1983 group died from RDS as opposed to 8% (13 of 156) of the infants from the LFUPP-1996/97 group (P < .001).
There was a trend toward higher mortality from cerebral causes in the LFUPP-1996/97 cohort: 24% versus 6% in the POPS-1983 cohort. This difference, however, did not reach significance (P = .06).
Neonatal Morbidity
A comparison of neonatal morbidity of the infants from the POPS-1983 and LFUPP-1996/97 groups is presented in Table 6. The incidence of RDS remained the same, 60% in both groups. In the LFUPP-1996/97 cohort, 24% (29 of 121) of infants whose mothers were treated antenatally with a full course of corticosteroids (2 doses) developed severe RDS (grade 3-4) compared with 45 (35%) of 126 in the incompletely or nontreated infants (P = .04). Of the 6 infants in the POPS-1983 who received corticosteroids antenatally, 2 developed (roentgenologically proven) RDS (33%).
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Pneumothorax was more frequently found in the POPS-1983 cohort; 15% of the infants had this complication as opposed to 6% in the LFUPP-1996/97 cohort. The percentage of infants who were mechanically ventilated was significantly higher in the LFUPP-1996/97 cohort: 78% of the infants versus 63% in the POPS-1983 group (P = .004). Infants from the LFUPP-1996/97 group were ventilated on average 3.8 days longer than the infants from the POPS-1983 group.
The incidence of BPD increased from 6% in the 1980s to 19% in the 1990s. No differences existed in incidences of patent ductus arteriosus; necrotizing enterocolitis; and neurologic disorders such as seizures, hydrocephalus, or central nervous system abnormalities during admission.
A trend toward less serious intraventricular hemorrhage (IVH) was found: the percentages of infants with grade 3 or 4 IVH remained approximately the same, but the percentage with grade 2 IVH decreased from 14% in the 1980s to 5% in the 1990s, whereas the percentage with IVH grade 1 increased from 7% to 13% (P = .02). In the LFUPP-1996/97 cohort, IVH occurred less frequently in infants whose mothers were treated antenatally with a full course of glucocorticosteroids: 81% (97 of 120) of the fully treated infants did not develop IVH compared with 69% (84 of 122) of the nontreated or incompletely treated infants (P = .09).
Sepsis (positive blood culture) occurred more frequently in the 1990s: 28% of the infants from the LFUPP-1996/97 group versus 16% in the POPS-1983 cohort (P = .03). The percentage of infants who were treated with antibiotics increased from 77% to 93% (P < .01).
The average length of stay in the hospital stayed almost the same: 66.9 days (SD: 22.5; range: 23-127) in the 1980s and 67.2 days (SD: 28; range: 13-215) in the 1990s (P = .9). The number of NICU days for survivors was almost equal as well: 41.2 days (SD: 27.3; range: 8-121) in the 1980s and 44.4 days (SD: 33.6; range: 1-215) in the 1990s (P = .8). However, including the infants who died, in determining NICU time, this increased from 26.7 days (SD: 31.5) in the 1980s to 40.7 days (SD: 34) in the 1990s (P = .002).
In conclusion, we found no difference in the incidence of RDS and severe IVH; a decrease in the incidence of pneumothorax and an increase in the incidences of BPD and sepsis was found. The deceased infants included, the number of days spent in NICU increased.
Condition at Discharge
Ten of the 102 patients of the POPS-1983 cohort were considered abnormal at discharge; 8 of these were encoded dubious and 2 were abnormal. The dubious cases were considered abnormal for the comparison.
In the total group of infants, adverse outcome (death or abnormal at discharge) was 41% (109 of 263) in the LFUPP-1996/97 group and 40% (41 of 102) in the POPS-1983 group (P = .8; Fig 3).
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27 weeks GA in both groups (Fig 3).
Of the surviving infants, condition at discharge was abnormal in 34% (80 of 234) of the infants in the LFUPP-1996/97 group and in 14% (10 of 71) in the POPS-1983 group (P = .001). None of the 4 surviving immature POPS-1983 infants were found to be abnormal; 73% (22 of 30) of the immature LFUPP-1996/97 infants were (P = .01). Twenty-eight percent (58 of 204) of the surviving LFUPP-1996/97 infants of 27 weeks' GA were abnormal; 15% (10 of 67) of the POPS-1983 infants were (P = .03).
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DISCUSSION |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONREFERENCES |
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Obstetrics
Obstetric management changed in respect to the percentage of mothers who were treated with corticosteroids antenatally, which increased significantly from 6% in 1983 to 73% in 1996–1997. The 6% in the 1980s cohort may seem somewhat low. This percentage did not seem to be a good reflection of the 17% treated with steroids antenatally in the total POPS-1983 cohort <32 weeks' GA. In 1983, glucocorticoids were not given antenatally in the Leiden University Medical Center. At the time, administration of glucocorticoids antenatally for the acceleration of pulmonary maturation was still a matter of debate in Netherlands; this therapy was restricted to 41 hospitals.7 Another possible explanation for the difference could be the percentage of mothers who were treated with the tocolytic ritodrine. Administration of this ß-agonist is an effective strategy to "buy time" for the administration of corticosteroids.8 The percentage of mothers who were treated with this drug was higher in the total POPS-1983 cohort (52%) compared with the regional cohort (39%). In the total cohort, 30% of the women who were treated with ß-agonists received corticosteroids as opposed to 4% of the women who were not treated with ß-agonists.
Mothers of the LFUPP-1996/97 cohort were more often treated with antibiotics than those of the POPS-1983 cohort. The percentage of PROM did not differ between the 2 groups; the percentage of mothers who had ruptured membranes and received antibiotics, however, was significantly higher in the LFUPP-1996/97 group. The percentage of membrane ruptures of longer duration (24 hours) was indeed higher in the LFUPP-1996/97 group, but treatment with antibiotics occurred more often in the group with ruptures of short duration (<24 hours) as well. Evidence that in women with PROM, treatment with antibiotics led to a significant prolongation of the pregnancy and a reduction in the incidence of chorioamnionitis and neonatal infection has probably resulted in an increased percentage of women receiving this treatment.9
Fourteen percent of the infants from the LFUPP-1996/97 group was born after assisted reproduction, mainly IVF (8%). Because most of these children were part of a twin or triplet, the 7% increase in the percentage of infants from multiple births that we found is most likely caused by the increased use of IVF (the first IVF infant in Netherlands was born in 1983).
Delivery/Birth Characteristics
A trend toward a higher percentage of 26- to 27-week-old infants delivered by cesarean section was found, which is probably the consequence of the better chance of survival that these infants now have, justifying the greater risk to which the mother is exposed when undergoing surgery than during natural child birth.
GA was certain in 95% in the 1990s and in 70% in the 1980s; the higher certainty level in the 1990s is very likely attributable to more early ultrasounds being made than in the early 1980s. The relatively low certainty level in the 1980s occurred throughout the GA range of 24 to 32 weeks, therefore probably not resulting in an outcome bias.
Centralization of perinatal care in the study region has increased: in 1983, 32% of the infants were born in centers with a NICU; in 1996–1997, this number increased to 62%. This increased centralization, not only in our study region but in the entire Netherlands, is mainly attributable to findings of the POPS-1983 study that showed that infants who were born in NICUs had lower mortality rates than infants who were transported extrauterinely.10–13 The still relatively large number of extrauterinely transported infants in the LFUPP-1996/97 group is caused by the fact that all infants who were treated in the Juliana Children's Hospital in The Hague (27%) were transported extrauterinely to this center because this hospital does not have an obstetric department.
Mortality
As could be expected, a significant decrease in overall mortality from 30% in the POPS-1983 group to 11% in the LFUPP-1996/97 group was found. For the extremely preterm infants (GA <27 weeks), mortality decreased from 76% to 33%. In both cohorts, the majority of infants died in the first week of life. In the POPS-1983 cohort, 71% died within 24 hours; in the LFUPP-1996/97 group, 34% did. This difference was not caused by a change in attitude toward treatment withdrawal, because this occurred in 40% of the infants who died within 24 hours in both cohorts. Mortality at later points was also found by Meadow et al14 in their recent study on changes in mortality for extremely low birth weight infants. Pulmonary problems were the main cause of mortality in both cohorts.
Morbidity
Many studies have shown a decrease in the incidence of RDS in infants whose mothers received antenatal steroids. Crowley,15 in his meta-analysis of randomized trials from 1972 to 1994, found that antenatal corticosteroid therapy results in an overall reduction of 50% in the odds of contracting neonatal RDS. Regarding these findings and the increased use of antenatal steroids, we expected to find a decrease in the incidence of RDS. The incidence of RDS, however, was approximately the same in the 1980s (57%) and 1990s (60%). Although the incidence of RDS remained the same, mortality from RDS significantly decreased. This suggests that the severity of RDS is reduced by antenatal treatment with corticosteroids. In the LFUPP-1996/97 cohort, we did indeed find a smaller percentage of infants with severe RDS within the group that was treated antenatally with a full course of corticosteroids than in the nontreated or incompletely treated infants. Besides this, survival of infants with severe RDS is now better because of treatment with surfactant.
The increased survival of infants with RDS was associated with an increase in the percentage of infants with BPD. BPD was defined according to Shennan in the LFUPP-1996/97 and according to Bancalari in the POPS-1983. The percentage of infants with BPD in the POPS-1983 cohort would probably have been even lower if the Shennan definition were used, because it is not likely that all infants who were oxygen dependent at 28 days post partum would still be at 36 weeks' postmenstrual age. Unfortunately, chart review of POPS cases to verify this did not yield the necessary data.
A shift toward less serious IVH was found. Although not significant, in the LFUPP-1996/97 cohort, IVH occurred less frequently in infants whose mothers were treated antenatally with a complete course of corticosteroids. A positive influence of antenatal corticosteroids on the incidence of IVH has been found in many studies. The previously mentioned meta-analysis by Crowley15 showed that corticosteroid therapy reduces the odds of periventricular hemorrhage (odds ratio [OR]: 0.38; 95% confidence interval: 0.23–0.94). Shankaran et al16 found an OR of 0.39 (95% confidence interval: 0.27–0.57) for the association of a complete course of steroids with grades 3 and 4 IVH.
Sepsis, defined as a positive blood culture, occurred more frequently in the LFUPP-1996/97 group. This could not be explained by a more frequent use of lines: 65% (163 of 249) of the LFUPP-1996/97 infants had a venous and/or arterial line, and 70% (69 of 99) of the POPS-1983 infants had a venous line. In the LFUPP-1996/97 infants, however, the lines were probably longer in situ because of the increased survival and mortality at later points (Fig 2), which could be an explanation of the increase in the occurrence of sepsis. Unfortunately, data about the exact number of days of line usage are not known in both cohorts, so this is only speculation. Another reason could be that detection techniques nowadays are better than before, leading to a higher number of positive blood cultures. In the Leiden University Medical Center, in the 1980s "homemade" culture bottles were used, whereas in the 1990s, these were replaced by industrial culture bottles (BATEC). Furthermore, Beganovic et al,17 in their article on the occurrence of sepsis in POPS-1983 infants who received total parenteral nutrition, described that of the clinically septic infants, only 29% had a positive blood culture.
Time spent in NICU stayed the same for surviving infants. Including the deceased, however, time spent in NICU increased with 14 days, reflecting mortality at later points in the 1990s.
The percentage of infants with an adverse outcome (death or abnormal) at discharge was comparable in both groups. Because mortality decreased considerably, this means that, in this study, increased survival resulted in more morbidity, at this age mainly BPD. The short-term outcome would be even more unfavorable for the LFUPP-1996/97 cohort if the dubious cases in the POPS-1983 cohort would have been considered normal.
We realize that in this comparison of many obstetric and neonatal data, the possibility exists that significant findings are chance findings. However, the significant differences found were mostly highly significant (P < .001), and most of them were based on clinical hypotheses, expected and in line with other publications, such as considerably less mortality and improvement of centralization of perinatal care.
In conclusion, we found in the studied Dutch health regions an increase in the absolute number of very preterm births between 1983 and 1996–1997. Mortality decreased considerably, but the increased number of surviving infants has resulted in more morbidity at the time of discharge from the hospital.
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ACKNOWLEDGMENTS |
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Other participants include the pediatric staff of 't Lange Land Hospital Zoetermeer (I. Hofmeier; H.C.J. Roggeveen), Rijnland Hospital Leiderdorp (P.E.C. Mourad-Baars), Diaconessen Hospital Leiden (A.C. Engelberts), Reinier de Graaf Hospital Delft (P.J.C. van der Straaten), and Antoniushove Hospital Leidschendam (Th. A. Nijenhuis), Netherlands.
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FOOTNOTES |
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Reprint requests to (S.V.) Neonatology, J6-S, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, Netherlands. E-mail: s.veen{at}lumc.nl
No conflict of interest declared.
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REFERENCES |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONREFERENCES |
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 P. Hovi, S. Andersson, J. G. Eriksson, A.-L. Jarvenpaa, S. Strang-Karlsson, O. Makitie, and E. Kajantie Glucose Regulation in Young Adults with Very Low Birth Weight N. Engl. J. Med., May 17, 2007; 356(20): 2053 - 2063. [Abstract] [Full Text] [PDF]
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T. M. O'Shea, S. Nageswaran, D. C. Hiatt, C. Legault, M. L. Moore, M. Naughton, D. J. Goldstein, and R. G. Dillard Follow-up Care for Infants With Chronic Lung Disease: A Randomized Comparison of Community- and Center-Based Models Pediatrics, April 1, 2007; 119(4): e947 - e957. [Abstract] [Full Text] [PDF]
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 N Finer To intubate or not--that is the question: continuous positive airway pressure versus surfactant and extremely low birthweight infants. Arch. Dis. Child. Fetal Neonatal Ed., November 1, 2006; 91(6): F392 - F394. [Full Text] [PDF]
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M. J.J. Finken, F. W. Dekker, F. de Zegher, J. M. Wit, and for the Dutch Project on Preterm and Small-for-Ges Long-term Height Gain of Prematurely Born Children With Neonatal Growth Restraint: Parallellism With the Growth Pattern of Short Children Born Small for Gestational Age Pediatrics, August 1, 2006; 118(2): 640 - 643. [Abstract] [Full Text] [PDF]
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