Table 3.

The potential variables included in each logistic regression model

Model	Category of variable	Variables
A	Crude analysis	N/A
B	Parental age	Maternal age, paternal age
C	Socioeconomic/demographic factors	Household income, maternal education, social deprivation, ethnicity, marital status
D	Maternal health factors	Maternal smoking, BMI, hypertension, diabetes, depression treatment
E	Combined	Household income, ethnicity, maternal smoking, BMI