Table 1.

Descriptive statistics for mothers in the study

Characteristic	N = 2961
Maternal age at measurement	27.82 (24.99, 30.79)
Days pregnant at measurement	207 (160, 288)
Current smoker?	17 (5.7%)
Grade completed	11.2 (2.0, 22.0)
SES z-score	0.06 (− 3.32, 5.10)
Pre-pregnancy BMI z-score	0.02 (− 1.89, 3.90)
Pregnancy number
1	41 (14%)
2	87 (29%)
3	67 (23%)
4	52 (18%)
5	25 (8.4%)
6 +	23 (8.1%)

¹Mean (range); n (%)