Table 1. Characteristics of VLBW infants in the NRN born Sept. 1, 1998 – Dec.31, 2009 who survived > 3 days—overall and with and without early onset sepsis (EOS).
| Characteristic, N (%) or Median (25th-75th percentile) 1/ |
Overall N=34396 |
Infants with EOS N=504 |
Infants without EOS N=33892 |
p-value 2/ |
|---|---|---|---|---|
| Mother’s age (years) | ||||
| Median (25th-75th p) | 27 (22-32) | 29 (23-34) | 27 (22-32) | <0.001 |
| Antenatal antibiotics | 21674 ( 64) | 370 ( 74) | 21304 ( 63) | <0.001 |
| Antenatal steroids | 27124 ( 79) | 386 ( 78) | 26738 ( 79) | 0.4 |
| Cesarean delivery | 22031 ( 64) | 294 ( 58) | 21737 ( 64) | 0.008 |
| Multiple birth | 8792 ( 26) | 84 ( 17) | 8708 ( 26) | <0.001 |
| Histologic chorioamnionitis 3/ | 2908/7514 (39) | 92/118 (78) | 2816/7396 (38) | <0.001 |
| Birth weight (grams) | ||||
| Median (25th-75th p) | 1039 (796-1280) | 909 (702-1170) | 1040 (800-1280) | <0.001 |
| l401-750 | 7123 ( 21) | 167 ( 33) | 6956 ( 21) | |
| l751-1000 | 8885 ( 26) | 134 ( 27) | 8751 ( 26) | |
| l1001-1250 | 8858 ( 26) | 116 ( 23) | 8742 ( 26) | |
| l1251-1500 | 9530 ( 28) | 87 ( 17) | 9443 ( 28) | |
| Gestational age (weeks) | ||||
| Median (25th-75th p) | 28 (26-30) | 27 (25-28) | 28 (26-30) | <0.001 |
| l<25 | 3965 ( 12) | 122 ( 24) | 3843 ( 11) | |
| l25-28 | 16157 ( 47) | 273 ( 54) | 15884 ( 47) | |
| l29+ | 14267 ( 41) | 109 ( 22) | 14158 ( 42) | |
| Small for gestational age4/ | 7210 ( 21) | 42 ( 8) | 7168 ( 21) | <0.001 |
| Male | 17231 ( 50) | 273 ( 54) | 16958 ( 50) | 0.07 |
| Race/ethnicity | ||||
| lNon-Hispanic black | 13183 ( 38) | 182 ( 36) | 13001 ( 38) | 0.27 |
| lNon-Hispanic white | 13781 ( 40) | 195 ( 39) | 13586 ( 40) | |
| lHispanic | 5794 ( 17) | 99 ( 20) | 5695 ( 17) | |
| lOther | 1574 ( 5) | 27 ( 5) | 1547 ( 5) | |
Information was missing for mother’s age: 11 infants, antenatal antibiotics during the delivery admission: 275, antenatal steroids: 160, cesarean delivery: 20, gestational age: 7, small for gestational age: 10, male sex: 3, race/ethnicity: 64.
P-value for a difference on the distribution of each characteristic in infants with EOS versus no EOS by the Wilcoxon test (median mother’s age, birth weight, gestational age), Fisher exact test or the general association chi-square test.
Beginning in 2006, information was collected about whether placental pathology was performed and chorioamnionitis documented. Numbers shown are among those with placental pathology performed (7576 of 9694 infants with information, 78%; 22% of the total cohort) for whom results were known [7514 infants; results were unavailable for 62 infants with placental pathology performed].
Growth charts developed by Alexander (Alexander, 1996) were used to classify infants as small for GA at birth (SGA), defined by a BW <10th percentile for sex and GA. Because eligibility for the NRN registry was based on low BW alone for most years studied, the proportion of infants SGA increased with increasing GA in this cohort. Thus, the percent SGA was lower among those with EOS than without.