Table 1 Background characteristics of pregnant women.

From: Birth and birth-related obstetrical characteristics in southwestern China associated with the current adjustment of family planning policy: a 7-year retrospective study

 

Periods

P-value

One-child policy

Selective two-child policy

Universal two-child policy

Age groups (years)a

   

 < 0.001

 < 20

0.5

0.5

0.3

 

 [20, 35)

89.4

88.7

83.9

 

 [35, 40)

8.0

8.5

12.9

 

≧ 40

2.1

2.3

2.9

 

Multiparitya

17.8

25.9

37.6

 < 0.001

Multiple pregnancy

2.5

3.1

3.1

0.001

IVF-ET

1.8

2.1

2.2

0.021

  1. Data are shown in percentage. Chi-squared test was used.
  2. IVF-ET in vitro fertilization and embryo transfer.
  3. aThose variables were chosen as subgroup factors and defined as covariates for further analysis.
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