Table 1. Maternal demographic characteristics.

	Euthyroid (n = 7641)	SCH (n = 371)	P
Maternal age (years)	27.12±0.05	26.33±0.24	0.243
Educational level			0.970
Primary school	607 (7.94%)	35 (9.43%)
Middle school	4465 (58.43%)	238 (64.15%)
College or university	2327 (30.45%)	84 (22.64%)
Parity			0.856
Nulliparity	6241 (81.68%)	299 (80.59%)
Multiparity	1400 (18.32%)	72 (19.41%)
Gestational age at delivery (weeks)	38.99±0.02	39.05±0.09	0.087
Mode of delivery			0.121
Vaginal	4876 (63.81%)	246 (66.31%)
Forceps	16 (0.21%)	2 (0.54%)
Cesarean	2749 (35.98%)	123 (33.15%)
Exposure to husbands’ smoking	3298 (43.16%)	166 (44.74%)	0.887

SCH, subclinical hypothyroidism.