Table 1 Patient demographics and baseline characteristics

N

805

723

Maternal age (years)

30.4 (5.0) [30,27–34]

27.8 (5.2) [27,24–31]

<.0001

Number of deliveries

2.4 (1.5) [2,1-3]

2.4 (1.3) [2,1-3]

0.13

Primiparity

256 (32%)

235 (33%)

0.77

Delivery week

39.4 (1.4)

[39.6,38.4–40.4]

39.3 (1.4)

[39.4,38.4–40.3]

0.20

Group of original study

Symptoms

391 (49%)

402 (56%)

0.006

Screening

414 (41%)

321 (44%)

Beta thalassemia minor

4 (0.5%)

22 (3%)

0.0001

Smoking

7 (0.9%)

1 (0.1%)

0.07

 City > 20,000 residents

441 (55%)

327 (45%)

0.0002

 Village ≤20,000 residents

364 (45%)

396 (55%)

Socio-Economic Index^a

(−0.1) (0.4)

[(− 0.1),(− 0.2)-(− 0.1)]

(− 1.1) (0.4)

[(− 1.2),(1.3)-(− 0.8)]

<.0001

Pre-pregnancy BMI

23.4 (4.4)

[22.5,20.6–25.5]

24.3 (4.6)

[23.6,21.3–26.8]

<.0001

Gestational diabetes mellitus

65 (8%)

74 (10%)

0.14

Pre-gestational diabetesmellitus

7 (0.9%)

5 (0.7%)

0.69

Chronic hypertension

8 (1%)

7 (1%)

0.95

Gestational hypertension

25 (3.1%)

25 (3.5%)

0.7

Epidural analgesia

370 (46%)

182 (25%)

<.0001

Labor induction

261 (32%)

297 (41%)

0.0005

Revision of uterine cavity and cervix (due to hemorrhage)

31 (4%)

28 (4%)

0.98

Manual removal of placenta

11 (1.4%)

8 (1.1%)

0.65

Vacuum extraction delivery

40 (5%)

19 (3%)

0.02

Prolonged second stage of delivery

27 (3.4%)

11 (1.5%)

0.02

Shoulder dystocia

6 (0.8%)

4 (0.6%)

0.76

Perineal tear ≥ grade 3

(involving anal sphincter)

5 (0.6%)

4 (0.6%)

1

Episiotomy

65 (8%)

67 (9%)

0.41