Table 1 Characteristics of the participants (n = 500)

Characteristics

n (%)

Mean ± SD or Median (IQR)

n (%)

Mean ± SD or Median (IQR)

Age (years)

29.5 ± 6.5

30.3 ± 6.4

0.413^a

  18-24.9

117 (26.8)

21.3 ± 2.0

15 (23.4)

21.5 ± 2.1

0.646^a

  25-34.9

199 (45.6)

29.5 ± 2.9

28 (43.8)

29.6 ± 2.9

0.832^a

  ≥ 35

120 (27.5)

37.6 ± 2.3

21 (32.8)

37.3 ± 6.3

0.538^a

Parity

  0

252 (57.8)

0

33 (51.6)

0

0.348^b

  ≥ 1

184 (42.2)

1 (1,2)

31 (48.4)

1 (1,2)

0.210^b

BMI (kg/m ² )

22.1 ± 4.0

22.9 ± 4.9

0.183^a

  ≤ 18

50 (11.5)

16.8 ± 0.8

5 (7.8)

16.1 ± 1.0

0.091^a

  18–25

300 (68.8)

21.2 ± 1.8

41 (64.1)

20.8 ± 1.9

0.246^a

  > 25

86 (19.7)

28.5 ± 3.3

18 (28.1)

29.4 ± 3.4

0.289^a

Current weight (kg)

58.9 ± 10.7

61.0 ± 13.5

0.156^a

  ≤ 60

268 (61.4)

52.3 ± 4.8

35 (54.7)

51.4 ± 5.4

0.292^a

  60.1–80

146 (33.4)

66.4 ± 4.8

20 (31.3)

65.8 ± 3.9

0.540^a

  > 80

22 (5.0)

88.7 ± 7.4

9 (14.1)

87.9 ± 4.1

0.743^a

Placental location

  Anterior

186 (42.7)

-

32 (50.0)

0.283^b

  Posterior

237 (54.4)

-

30 (45.9)

0.285^b

  Fundus

13 (3.0)

-

2 (3.1)

> 0.99^b

LUW thickness (mm)

6.25 ± 1.46

6.02 ± 1.37

0.230^a

  < 4.5

31 (7.1)

3.9 ± 0.4

9 (14.1)

3.9 ± 0.3

0.785^a

  ≥ 4.5

405 (92.9)

6.4 ± 1.3

55 (85.9)

6.3 ± 1.1

0.687^a

Route of delivery

  Spontaneous vaginal delivery

263 (60.3)

-

38 (59.4)

-

0.892^b

  Cesarean section

164 (37.6)

-

25 (39.1)

-

0.890^b

  Vacuum extraction

9 (2.1)

-

0

-

-

  Forceps extraction

0

-

1 (1.6)

-

-

Birth weight (g)

3134.4 ± 429.2

2417.2 ± 480.2

< 0.005^a

  < 1,500

0

-

3 (4.7)

1173.3 ± 324.7

-

  1,500–2,499

18 (10.8)

2368.3 ± 145.6

36 (56.3)

2224.0 ± 229.2

0.019^a

  2,500–3,999

402 (85.4)

3119.1 ± 320.4

25 (39.1)

2844.7 ± 283.2

< 0.005^a

  ≥ 4,000

16 (3.2)

4380.0 ± 456.2

0

-

-