Table 4 Univariate and multivariate analysis to examine the risk factor of severe PPH^a in pregnant women with placenta previa

Maternal age

  > 35 years vs. < 35 years

1.19

(0.55–2.59)

0.66

Gestational age at delivery

  > 37 weeks vs. < 37 weeks

1.03

(0.46–2.32)

0.94

Parity

 Primipara vs Multipara

0.43

(0.19–0.98)

0.04

0.95

(0.27–3.33)

0.93

In vitro fertilization pregnancy

 Yes vs. No

0.80

(0.23–2.78)

0.73

Tocolytic agent use

 Yes vs. No

1.26

(0.58–2.74)

0.56

Warning bleeding^b

 Yes vs. No

1.40

(0.62–3.16)

0.41

Prior CS

 Yes vs. No

9.23

(4.02–21.20)

 < 0.01

4.71

(1.29–17.13)

0.02

The mode of cesarean section

 Emergency vs. Elective

0.98

(0.38–2.51)

0.96

The classification of placenta previa

 Major previa^c vs. Minor previa^d

11.35

(3.35–38.38)

 < 0.01

7.50

(1.98–28.43)

 < 0.01

Main location of placenta

 Anterior wall vs. Posterior wall

3.44

(1.40–8.44)

 < 0.01

1.83

(0.56–6.00)

0.32

Placenta accreta spectrum

 Yes vs. No

16.47

(4.66–58.26)

 < 0.01

2.53

(0.39–16.46)

0.33

Prior endometrial curettage

 Yes vs. No

0.71

(0.28–1.82)

0.48

Retained products of conception

 Yes vs. No

29.70

(11.23–78.55)

 < 0.01

13.26

(3.61–48.63)

 < 0.01