Table 1.

Demographic information of pregnant women in Jiangsu Province from April 2013 to July 2016 ($n=\mathrm{1,024}$).

Maternal characteristic	$\text{Mean}\pm \text{SD}$ or $n$ (%)
Maternal age (y)	$28.8\pm 3.7$
Ethnicity
Han	999 (97.6)
Other	25 (2.4)
Maternal height (cm)	$161.7\pm 5.0$
Weight before pregnancy (kg)	$54.9\pm 7.8$
BMI before pregnancy (${\mathrm{kg}/\mathrm{m}}^2$)	$21.0\pm 2.8$
Parity
0	814 (79.5)
$\ge 1$	210 (20.5)
Education (y)
$\le 12$	446 (43.6)
$\ge 13$	578 (56.4)
Smokinga
Yes	23 (2.2)
No	1,001 (97.8)
Alcohol consumptiona
Yes	40 (3.9)
No	984 (96.1)

Note: These data were complete for all participants. BMI, body mass index.

^a Reported “yes” at least one time in the first, second, or third trimester.