Table 1.
Infant demographics for the three independent cohorts used in this study.
| Full-term | Very preterm | Late preterm | |||
|---|---|---|---|---|---|
| Number of participants | 15 | 10 | 8 | ||
| Female | 6 | 5 | 3 | ||
| Gestational age at birth (weeks) | 38.2 (36.1–41.0) | 29.0 (27.1–31.4) | 34.7 (34–35.7) | ||
| Birthweight (g) | 3166 (2130–4590) | 1173 (760–1900) | 2449 (1550–4525) | ||
| Antenatal factors | |||||
| Prolonged rupture of membranes | 1 | 5 | 2 | ||
| Intrauterine growth restriction (IUGR)1 | 1 | 3 | 2 | ||
| Abnormal Doppler | 0 | 1 | 1 | ||
| Maternal infection (Chorioamnionitis) | 0 | 4 | 0 | ||
| Delivery | |||||
| Vaginal (assisted/unassisted) | 8 | 2 | 5 | ||
| Caesarean | 7 | 8 | 3 | ||
| Apgar score at 10 mins | 10 | 9 (8–10) | 9.75 (8–10) | ||
| Conditions during admission in NICU | |||||
| Neurological conditions | 0 | 1* | 0 | ||
| Cardiac conditions | 0 | 1** | 0 | ||
| Respiratory distress syndrome | 1 | 7 | 1 | ||
| Invasive mechanical ventilation < 24 hrs | 0 | 2 | 3 | ||
| Invasive mechanical ventilation > 24 hrs | 0 | 2*** | 0 | ||
| Infection suspected | 1 | 4 | 2 | ||
| Previous surgery | 0 | 0 | 0 | ||
| Test occasion | <32 | 32–34 | 34–37 | ||
| Postmenstrual age at study (weeks) | 38.5 (36.6–41.7) | 30.4 (28–31.9) | 32.7 (32–33.3) | 35.1 (34.3–36.3) | 35.5 (34.7–36.4) |
| Postnatal age at study (days) | 3.7 (1–7) | 9.8 (5–15) | 23.6 (15–36) | 44 (36–58) | 5.9 (4–10) |
| Respiratory support (LFT/HFT) at study | 0 | 5 | 5 | 4 | 0 |
| Non-standard drugs2at study – Budesonide | 0 | 0 | 1 | 1 | 0 |
| Analgesics < 24 hrs prior to study | 0 | 0 | 0 | 0 | 0 |
| Antibiotics at study | 1 | 1 | 0 | 0 | 0 |
| Prior pain | 2 (0–23) | 21.3 (11–46) | 33.9 (22–59) | 37.5 (25–65) | 10 (3–21) |
* Choroid plexus cyst.
** Patent ductus arteriosus (PDA).
*** Infants were ventilated for a maximum of 4 days and did not require further periods of ventilation.
LFT = Oxygen therapy.
HFT = High flow nasal cannulae.
Prior pain = number of skin breaking procedures and endotracheal tube/oral suction.
For age, birthweight, and prior pain, values are presented as means (accumulative mean for prior pain) with range in parentheses.
1
IUGR is defined as any baby whose weight is below the 10th percentile for their gestational age.
2
Standard drugs include: Caffeine citrate, Vitamins, Probiotics, Breast milk fortifier, Iron, Sodium and Phosphate supplements.