Table 1.
Participant and sampling demographics.
| Term group (≥ 37weeks GA) | Preterm group (32 ≤ weeks GA) | |
|---|---|---|
| Mothers, n | n = 50 | n = 43 |
| Age (years) | 34.1 ± 4.5 | 31.9 ± 5.9 |
| Body mass index (kg/m2) | 24.9 ± 4.3 | 25.5 ± 5.9 |
| Tobacco smoked during pregnancy, n (%) | 0 (0%) | 7 (16%) |
| Received a single course of antenatal Steroids, n (%) | 0 (0%) | 43 (100%) |
| Labour onset, n (%) | ||
| Spontaneous | 26 (52%) | 25 (58%) |
| Induced | 15 (30%) | 2 (5%) |
| Mode of Delivery, n (%) | ||
| Spontaneous vaginal delivery | 26 (52%) | 17 (40%) |
| Instrumental delivery | 8 (16%) | 2 (5%) |
| Pre-labour caesarean section | 9 (18%) | 16 (37%) |
| In labour caesarean section | 7 (14%) | 8 (19%) |
| Infant characteristics, n (%)a | n = 49 | n = 59 |
| Hair collected at Time-points 1 and 2 | 0 (0%) | 42 (71%) |
| Hair collected at Time-point 1 only | 49 (100%) | 5 (8%) |
| Hair collected at Time-point 2 onlyb | 0 (0%) | 12 (20%) |
| Birthweight (grams), mean (range) | 3536 (2410, 4580) | 1332 (454, 2380) |
| Birth weight z-score | 0.5 ± 1.0 | 0.1 ± 1.1 |
| Birth gestation (weeks), mean (range) | 40.0 (37.6, 42.1) | 29.4 (24.0, 32.0) |
| < 28 weeks gestation age at birth, n (%) | Not applicable | 15 (25%) |
| Female, n (%) | 25 (51%) | 19 (32%) |
| Twin, n (%) | 0 (0%) | 18 (31%) |
| Exposure to histological chorioamnionitis, n (%)c | 4 (16%) | 21 (38%) |
| Received postnatal hydrocortisone, n (%) | 0 (0%) | 11 (19%) |
| Neonatal sepsis, n (%) | 0 (0%) | 9 (15%) |
| Sample Characteristics | ||
| Maternal sample: Days after birth | 2 (1–5) | 4 (2–6) |
| Infant sample (time-point 1): Days after birth | 2 (1–5) | 4 (3–6) |
| Infant sample (time-point 2): Days after birth | Not applicable | 44 (42–49) |
Data are presented as mean ± SD if normally distributed, and mean (range) if skewed.
a
In infants of mothers with hair sampled, hair was not collected in 1 term infant (whose parents did not consent for infant hair sampling, and 4 preterm participants (due to insufficient hair)).
b
12 preterm infants had hair sampled only at time-point 2 as parental consent for study entry was given after the first 10 days of life.
c
N = 24 term placentas (n = 19 due to postnatal recruitment) and n = 3 preterm placentas where not assessed for chorioamnionitis