Antenatal and perinatal characteristics and major neonatal morbidities among infants followed-up and lost to follow-up
| Characteristic | Lost to follow-up (n=497) | Followed-up (n=1473) | p Value |
|---|---|---|---|
| Maternal age, years | 27.0 (22.0–32.0) | 30.0 (26.0–34.0) | <0.01 |
| Aboriginal ethnicity | 35 (7.0) | 21 (1.4) | <0.01 |
| Primipara | 129 (26.0) | 489 (33.2) | <0.01 |
| Assisted conception | 34 (6.8) | 217 (14.7) | <0.01 |
| Multiple pregnancy | 114 (22.9) | 392 (26.6) | 0.12 |
| Pregnancy induced hypertension | 50 (10.1) | 261 (17.7) | <0.01 |
| Ante-partum haemorrhage | 170 (34.2) | 439 (29.8) | 0.08 |
| Gestational diabetes | 5 (1.0) | 33 (2.2) | 0.12 |
| Any antenatal corticosteroid | 429 (86.3) | 1323 (89.8) | 0.04 |
| Chorioamnionitis* | 73/327 (22.3) | 164/764 (21.4) | 0.80 |
| Vaginal breech | 41 (8.2) | 149 (10.1) | 0.26 |
| Caesarean section in labour | 128 (25.8) | 339 (23.0) | 0.23 |
| Born in non-tertiary centre | 82 (16.5) | 109 (7.4) | <0.01 |
| Apgar score <7 at 5 min | 86 (17.3) | 282 (19.1) | 0.41 |
| Male gender | 261 (52.5) | 787 (53.4) | 0.76 |
| Gestational age, weeks | 27.0 (26.0–28.0) | 27.0 (26.0–28.0) | 1.00 |
| Birth weight , grams | 1029.0 (866.5–1187.5) | 945.0 (776.0–1110.0) | <0.01 |
| Birth weight <10th percentile | 26 (5.2) | 152 (10.2) | <0.01 |
| Head circumference, cm | 25.5 (24.0–26.5) | 24.3 (23.3–26.0) | <0.01 |
| Head circumference <10th percentile | 25 (5.0) | 118 (8.0) | 0.02 |
| Admitted after office hours | 326 (65.6) | 972 (66.0) | 0.92 |
| Surfactant therapy | 299 (60.2) | 1051 (71.4) | <0.01 |
| Mechanical ventilation | 384 (77.3) | 1286 (87.3) | <0.01 |
| Duration of ventilation, days | 4.6 (2.0–14.34) | 7.9 (3.0–21.1) | <0.01 |
| PDA requiring treatment | 190 (38.2) | 647 (43.9) | 0.03 |
| Proven systemic infection | 141 (28.4) | 595 (40.4) | <0.01 |
| IVH grade 3 or 4† | 22/496 (4.4) | 93/1472 (6.3) | 0.16 |
| Necrotising entercolitis | 18 (3.6) | 56 (3.8) | 0.95 |
| Chronic lung disease | 133 (26.8) | 596 (40.5) | <0.01 |
| Post-natal steroid for CLD | 78 (15.7) | 408 (27.7) | <0.01 |
| Home oxygen | 58 (11.7) | 306 (20.8) | <0.01 |
| ROP grade 3 or 4† | 36/481 (7.5) | 187/1456 (12.8) | <0.01 |
| Length of NICU stay, days | 74.0 (63.0–93.0) | 82.0 (69.0–102.0) | <0.01 |
Data are presented as n (%) or median (IQR). Followed-up group was set as a referent for OR and 95% CI calculation.
*Chorioamnionitis including clinically suspected cases. Data collected from 2001 onwards. Denominator is number of total followed-up from 2001 onwards.
†Denominator is number of infants examined.
CLD, chronic lung disease; IVH, intraventricular haemorrhage; NICU, neonatal intensive care unit; PDA, patent ductus arteriosus; ROP, retinopathy of prematurity.