Table 2.

Basic information of research objects.

Group	N	Pregnancy times (times)	Gestational week of blood collection in the first trimester (weeks)	Gestational week of blood collection in the third trimester (week)	BMI before pregnancy (kg/m2)
Normal pregnancy	200	1.98 ± 0.97	10.94 ± 1.26	34.13 ± 1.02	21.55 ± 1.47
Hypertension during pregnancy	78	1.79 ± 0.77	11.02 ± 1.25	34.03 ± 1.10	21.58 ± 1.47
Pre-eclampsia	46	2.07 ± 0.96	10.75 ± 1.12	34.20 ± 1.03	21.63 ± 1.45
Severe pre-eclampsia	37	1.84 ± 0.79	11.10 ± 1.15	34.39 ± 1.14	22.01 ± 1.34
P	—	>0.05	>0.05	>0.05	>0.05