Table 1.

Comparison of general information between the two groups (n)

Groups	Observation group (n=30)	Control group (n=60)	χ2/t	P
Age (year)	27.4±2.7	27.1±2.3	0.550	0.584
Gestational age (week)	38.2±1.5	38.4±1.6	0.571	0.570
Number of pregnancies			2.537	0.111
The first time	24	55
≥2 times	6	5
History of abortion	6	8	0.667	0.411
BMI (kg/m2)	24.23±2.61	23.92±2.83	0.502	0.617
Comorbidities
Gestational hypertension	6	13	0.033	0.855
Gestational diabetes	8	10	0.478	0.489

Note: BMI: body mass index.