Table 2

Selected participant characteristics and associations with neurodevelopmental outcome in four key domains

	Cognitive Development^a			Expressive Language^a			Externalising^b			Internalising^b
	Mean	95 % CI	P value	Mean	95 % CI	P value	Mean	95 % CI	P value	Mean	95 % CI	P value
	Difference	95 % CI	P value	Difference	95 % CI	P value	Difference	95 % CI	P value	Difference	95 % CI	P value
Socio-economic and demographic factors
Maternal age:
<25 years	−1.7	−2.8, –0.52	0.005	−1.7	−3.5, –0.020	0.05	6.5	3.3, 9.7	<0.001	4.6	1.4, 7.9	0.005
25–40 years	Reference			Reference			Reference			Reference
>40 years	−1.4	−2.9, 0.15	0.08	−0.63	−2.8, 1.6	0.57	−4.3	−8.1, –0.42	0.03	-3.0	−6.9, 0.83	0.12
Median parental education category^c	0.84	0.55, 1.1	<0.001	1.0	0.62, 1.5	<0.001	−0.66	−1.4, 0.077	0.08	−0.43	−1.2, 0.30	0.25
Mean annual household income antenatal & first year (10 000 AUD units)	0.19	0.051, 0.33	0.008	0.24	0.042, 0.45	0.02	−0.91	−1.3, –0.55	<0.001	−0.84	−1.2, –0.48	<0.001
Household composition factors
Total household size at birth	−0.66	−0.96, –0.36	<0.001	-1.0	−1.4, –0.61	<0.001	−0.063	−0.83, 0.71	0.87	−1.3	−2.1, –0.57	0.001
Total number of siblings at birth	−0.61	−0.94, –0.29	<0.001	−1.1	−1.6, –0.69	<0.001	0.063	−0.77, 0.89	0.88	−1.5	−2.4, –0.73	<0.001
Lone parent household	−0.57	−2.2, 1.0	0.49	−0.58	−2.8, 1.7	0.61	1.8	−2.5, 6.2	0.40	4.7	0.37, 9.0	0.03
Cultural-linguistic factors
Number of grandparents identifying as Aboriginal or Torres Strait Islander	−1.1	−2.7, 0.45	0.16	−0.96	−3.1, 1.2	0.37	0.76	−3.4, 4.9	0.72	0.36	−3.8, 4.5	0.86
Maternal country of birth:
Australia	Reference			Reference			Reference			Reference
Majority English-speaking country	−0.39	−1.6, 0.81	0.52	−1.7	3.5, 0.0030	0.05	4.4	1.5, 7.3	0.003	2.1	−0.84, 5.0	0.16
Other country	−1.1	−2.5, 0.30	0.13	−0.94	−3.0, 1.1	0.36	−1.1	−4.7, 2.6	0.56	1.8	−1.8, 5.5	0.33
Antenatal health, diet & exposures
Maternal diet – total fish (g/day)	0.0013	−0.0094, 0.012	0.81	0.0041	−0.010, 0.020	0.58	0.0022	−0.025, 0.029	0.87	0.017	−0.010, 0.043	0.22
Any fish oil supplements in pregnancy	0.63	0.074, 1.2	0.03	0.74	−0.046, 1.5	0.06	0.49	−0.91, 1.9	0.49	−0.55	−2.0, 0.87	0.45
Average alcohol intake trimester 1 (standard drinks):
Nil	Reference			Reference			Reference			Reference
<1 a week	0.099	−0.54, 0.74	0.76	−0.68	−1.6, 0.22	0.14	0.48	−1.1, 2.1	0.56	0.19	−1.4, 1.8	0.82
1–6 a week	0.13	−0.91, 1.2	0.81	−1.8	−3.2, –0.29	0.02	0.78	−1.9, 3.5	0.57	1.5	−1.2, 4.2	0.27
1–3 a day	−1.9	−6.1, 2.3	0.37	−2.6	−9.2, 4.0	0.44	−0.45	−11, 10	0.93	3.2	−7.3, 14	0.55
(test of trend)			0.92			0.008			0.49			0.29
Number of occasions>5 standard drinks at a time over trimester 1	0.097	−0.31, 0.51	0.64	−0.55	−1.2, 0.08	0.09	0.59	−0.49, 1.7	0.29	1.1	0.019, 2.2	0.05
Maternal smoking (timing over this pregnancy):
Nil	Reference			Reference			Reference			Reference
Early but stopped	0.61	−0.44, 1.7	0.26	0.064	−1.4, 1.5	0.93	2.9	0.26, 5.5	0.03	4.1	1.5, 6.7	0.002
Early and late	−0.64	−2.2, 0.87	0.40	−2.7	−5.0, –0.35	0.02	2.8	−0.89, 6.4	0.14	2.2	−1.4, 5.9	0.23
Any maternal recreational drug use in this pregnancy (marijuana)	1.4	−1.4, 4.1	0.33	0.24	−3.6, 4.1	0.90	7.5	1.8, 13	0.01	3.9	−1.8, 9.6	0.18
Birth outcomes
Prematurity^d:
Term	Reference			Reference			Reference			Reference
Late preterm	−0.39	−2.0, 1.2	0.63	0.82	−1.7, 3.4	0.53	−0.18	−4.1, 3.7	0.93	1.2	−2.8, 5.1	0.56
Moderate preterm	−2.9	−6.5, 0.77	0.12	−7.1	−14, –0.51	0.03	1.5	−7.6, 11	0.75	5.4	−3.6, 14	0.24
Mode of delivery:
Unassisted vaginal	Reference			Reference			Reference			Reference
Assisted vaginal	−0.20	−0.94, 0.53	0.59	0.029	−1.0, 1.1	0.96	0.12	−1.7, 1.9	0.90	1.6	−0.22, 3.4	0.09
Unscheduled caesarean	0.31	−0.53, 1.1	0.47	0.87	−0.33, 2.1	0.15	−0.26	−2.4, 1.8	0.81	1.6	−0.52, 3.6	0.14
Elective caesarean	−0.17	−0.99, 0.65	0.68	−0.22	−1.3, 0.91	0.70	−1.4	−3.4, 0.61	0.17	−2.2	−4.1, –0.20	0.03
Apgar score at 5 min	−0.011	−0.38, 0.36	0.95	0.25	−0.31, 0.81	0.38	−1.2	−2.1, –0.42	0.003	−0.23	−1.0, 0.59	0.59
Postnatal
Breastmilk feeding (duration):
Nil or <1 week	-1.0	−2.7, 0.60	0.21	−3.4	−5.6, –1.2	0.003	2.6	−1.0, 6.3	0.16	1.1	−2.5, 4.7	0.56
>=1 week but <6 months	−0.85	−1.5, –0.25	0.006	−1.3	−2.1, –0.41	0.004	0.025	−1.5, 1.6	0.98	−0.9	−2.4, 0.64	0.25
>=6 months	Reference			Reference			Reference			Reference
Maternal stress & mental health
Edinburgh Depression Scale (pregnancy):
Low Risk (<10)	Reference			Reference			Reference			Reference
Moderate Risk	−0.52	−1.5, 0.49	0.31	0.029	−1.5, 1.5	0.97	4.1	1.3, 7.0	0.005	5.8	3.1, 8.6	<0.001
High Risk (>12)	−0.34	−1.8, 1.1	0.64	−0.93	−2.8, 1.0	0.34	0.66	−3.4, 4.7	0.75	4.5	0.56, 8.4	0.03
Mean Perceived Stress Scale score (pregnancy, 4 weeks, 6 months)	−0.013	−0.059, 0.033	0.57	−0.02	−0.084, 0.043	0.53	0.35	0.24, 0.47	<0.001	0.42	0.31, 0.53	<0.001
Parenting practices
HOME-SF Emotional Support subscale (9 months, n=275–334)	0.024	−0.42, 0.47	0.92	0.3	−0.36, 0.97	0.37	0.54	−0.65, 1.7	0.37	0.59	−0.52, 1.7	0.30
HOME-SF Cognitive Stimulation subscale (9 months, n=275–334)	0.18	−0.12, 0.48	0.23	0.33	−0.090, 0.76	0.13	0.12	−0.68, 0.92	0.77	−0.18	−0.93, 0.56	0.63

*Estimated change in raw score on the BAYLEY-III adjusting for sex, postconceptional age, researcher, researcher experience (number of prior assessments within study) and excluding twins, those with known acquired neurodevelopmental disorders, and those outside of age criteria of 2–3 years.
†Estimated change in T-score for problem behaviours reported on the Child Behaviour Checklist for Ages 1½−5 adjusting for sex and chronological age and excluding twins, known acquired neurodevelopmental disorders.
‡Highest level of education attained (six categories: <10 years of school, 10–11 years of school, completed year 12, trade certificate/apprenticeship or diploma, undergraduate degree, postgraduate degree).
§Note that the associations reported here between prematurity and BAYLEY-III measures (cognitive development and expressive language) are after adjustment for postconceptional age.
BAYLEY-III, Bayley Scales of Infant and Toddler Development, Third Edition; HOME-SF, Home Observation for Measurement of the Environment-Short Form.