Table A.2.

Brain Derived Neurotrophic Factor (BDNF) in infancy and children’s developmental delay in the primary cohort (alternative cut-off)

	Child Development
Exposure: BDNF levels	Fine motor	Gross motor	Communication	Personal-social	Problem solving
	OR (95%CI) Random intercept variability (SE) BIC	OR (95%CI) Random intercept variability (SE) BIC	OR (95%CI) Random intercept variability (SE) BIC	OR (95%CI) Random intercept variability (SE) BIC	OR (95%CI) Random intercept variability (SE) BIC
Unadjusted	0.58 (0.33, 1.02) 7.16 (0.41) 7407.02	0.50 (0.27, 0.94)* 7.16 (0.44) 5055.32	0.45 (0.25, 0.82)* 8.17 (0.49) 6392.33	0.42 (0.24, 0.74)* 6.69 (0.41) 6066.81	0.53 (0.30, 0.95)* 7.51 (0.46) 6550.98
Adjusted	0.68 (0.38, 1.22) 7.05 (0.43) 7328.95	0.61 (0.33, 1.14) 7.21 (0.48) 5004.21	0.63 (0.33, 1.20) 8.32 (0.56) 6273.5	0.57 (0.33, 0.98)* 6.26 (0.40) 5978.04	0.67 (0.36, 1.23) 7.48 (0.49) 6457.89

BIC: Bayesian Information Criterion; OR: Odds Ratio; CI: Confidence Interval; SE: Standard Error

Primary cohort: singletons and one randomly selected twin of each pair

Developmental delay was assessed up to age 3 years using the Ages and Stages Questionnaires.

BDNF had a skewed distribution and therefore was log-transformed.

Models were adjusted for child gender, preterm birth, parity, infertility treatment, maternal age, race, education, history of smoking and drinking, pre-pregnancy body mass index, and having private insurance.

^*denotes P values <0.05