Table 3.
Demographic characteristics of participants
| Demographics for combined NZ and IRE cohorts (n = 63) | |||
|---|---|---|---|
| Variables | Cases (n = 25) | Controls (n = 38) | p-value |
| Age (maternal), years | 30.4 (5.7) | 30.6 (3.6) | 0.9 |
| Birthweight, g | 3604.0 (666.0) | 3439.0 (431.0) | 0.2 |
| Sex (infant) | 0.02 | ||
| Male | 23 (92) | 25 (66) | |
| Female | 2 (8) | 13 (34) | |
| Mode of delivery | 0.04 | ||
| Unassisted vaginal | 9 (36) | 16 (42) | |
| Assisted vaginal | 4 (16) | 15 (40) | |
| Pre-labour LSCS | 1 (4) | 2 (5) | |
| Labour LSCS | 11 (44) | 5 (13) | |
| Gestational age at delivery | 39.9 (1.5) | 40.0 (1.4) | 0.9 |
| 1-min Apgar | 0.08 | ||
| < 7 | 2 (8) | 0 | |
| ≥ 7 | 23 (92) | 38 (100) | |
| 5-min Apgar | * | ||
| < 7 | 0 | 0 | |
| ≥ 7 | 25 (100) | 38 (100) | |
| Ethnicity | 1 | ||
| Caucasian | 23 (92) | 35 (92) | |
| Non-Caucasian | 2 (8) | 3 (8) | |
| SEI (maternal) | 52.6 (16.2) | 49.8 (11.7) | 0.4 |
| Household income | 0.4 | ||
| Unknown | 2 (8) | 2 (5) | |
| < $75 K (< €64 K) | 6 (24) | 11 (29) | |
| $75–100 K (€64–84 K) | 10 (40) | 8 (21) | |
| > $100 K (> €85 K) | 7 (28) | 17 (45) | |
| Smoking status in pregnancy | 0.4 | ||
| No, never smoked | 20 (80) | 24 (63) | |
| No, ex-smoker | 4 (16) | 11 (29) | |
| Yes, current smoker | 1 (4) | 3 (8) | |
| PSS (perceived stress score) | 13.8 (7.3) | 14.7 (6.7) | 0.6 |
| BMI (WHO categories) | 0.2 | ||
| Underweight/Normal (≤ 25 kg/m2) | 14 (56) | 27 (71) | |
| Overweight/Obese (> 25 kg/m2) | 11 (44) | 11 (29) | |
| Folate—pre-conceptual | 0.6 | ||
| No | 9 (36) | 11 (29) | |
| Yes | 16 (64) | 27 (71) | |
| Folate—15 week visit | 0.02 | ||
| No | 3 (12) | 15 (40) | |
| Yes | 22 (88) | 23 (61) | |
Comparison is made between cases and controls across the whole cohort. p-Values are calculated using the Pearson Chi square for categorical data, and independent samples t-test where appropriate for continuous variables. Variations in local Caesarean section practices from each site likely give rise to the significant difference in Mode of Delivery rates. Eight of eleven (73%) of the ASD cases delivered by lower segment Caesarean section—“Labour LSCS” were in NZ. “Pre-labour LSCS” was excluded when identifying confounding variables due to small sample numbers (n = 3). There are no significant differences in birth weight, either between cases and controls, or between subjects from each site. Numbers are presented as mean (SD) or n (%)