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Table 1 The Characteristics of Demographics and Obstetrics

From: How does the two-child policy affect the sex ratio at birth in China? A cross-sectional study

 

BTCP

n = 76,466

OTCP

n = 77,481

UTCP

n = 116,931

F/χ2

P value

Maternal age (year)a

27.2 ± 4.6

27.7 ± 4.7d1

28.7 ± 4.6 d2,d3

2708.69

< 0.01

 < 20 yearsb

1453(1.9)

1294(1.7)

1277(1.1)

5832.92

< 0.01

 20–24 yearsb

19,958(26.1)

16,664(21.5)

17,486(15.0)

 25–29 yearsb

36,188(47.3)

37,128(47.9)

55,035(47.1)

 30–34 yearsb

14,059(18.4)

16,056(20.7)

29,702(25.4)

 ≥ 35 yearsb

4800(6.3)

6323(8.2)

13,405(11.5)

 Unknown

8(0.0)

16(0.0)

26(0.0)

Delivery modeb

   

90.81

< 0.01

 Vaginal

35,616(46.6)

37,968(49.0)d1

57,112(48.8) d2,f3

  

 Cesarean

40,833(53.4)

39,510(51.0)

59,814(51.2)

  

 Unknown

17(0.0)

3(0.0)

5(0.0)

  

Gestational age (weeks) a

38.9 ± 1.9

38.9 ± 1.7 f1

38.7 ± 1.7 d2,d3

117.36

< 0.01

Parityb

   

4824.41

< 0.01

 Nulliparous

45,346(59.3)

40,944(52.8)d1

50,793(43.4) d2,d3

  

 Multiparous

31,120(40.7)

36,537(47.2)

66,138(56.6)

  

Educationb

   

27.57

< 0.01

 College and above

21,564(28.2)

23,096(29.8)d1

43,140(36.9) d2,d3

  

 Middle school

52,462(68.6)

51,683(66.7)

69,754(59.7)

  

 Primary school and below

1963(2.6)

1767(2.3)

2041(1.7)

  

 Unknown

477(0.6)

935(1.2)

1996(1.7)

  

Marital statusb

   

3.97

< 0.05

 Married

76,013(99.4)

77,137(99.6)d1

116,430(99.6) d2,f3

  

 Single

438(0.6)

326(0.4)

473(0.4)

  

 Unknown

15(0.0)

18(0.0)

28(0.0)

  

Delivery hospitalb

   

401.63

< 0.01

 Urban

33,537(43.9)

35,554(45.9)d1

56,678(48.5) d2,d3

  

 Rural

42,928(56.1)

41,924(54.1)

60,249(51.5)

  

 Unknown

1(0.0)

3(0.0)

4(0.0)

  

Baby sexb

   

13.22

< 0.01

 Female

36,686(48.0)

37,790(48.8)d1

57,133(48.9) d2f3

  

 Male

39,780(52.0)

39,691(51.2)

59,798(51.1)

  

SRBc, a

1.084

1.050d1

1.047 d2,f3

15.97

< 0.01

Birth weight (kg) a

3.34 ± 0.52

3.33 ± 0.52 d1

3.34 ± 0.51 f2,d3

10.29

< 0.01

Neonatal deathc

0.912

1.110

1.130

  

 Male neonatal deathb

283(44.0)

253(48.5) d1

340(49.7) d2,d3

15.29

< 0.01

 Female neonatal deathb

310(48.2)

228(43.7)

301(43.9)

30.83

< 0.01

 Unknownb

50(7.8)

41(7.8)

44(6.4)

  

Deliveries per daye

141(121, 163)

116(90, 162) d1

154(130, 181) d2,d3

47.98

< 0.01

  1. BTCP: Both the husband and wife of one couple were the only child of their parents, the couple were allowed to have Two Children in Policy (January 1, 2013 - May 29, 2014); OTCP: only the husband or wife of one couple was the only child of their parents, the couple were allowed to have Two Children in Policy (May 30, 2014 - December 31, 2015); UTCP: the Universal Two-Child Policy, every couple were allowed to have two children (January 1, 2016 - December 31, 2017). SRB: Sex Ratio at Birth. A analysis of variance test of Post Hoc Multiple Comparisons was used for normally continuous variables, and chi-square test for the categorical variables;
  2. aThe normal distribution continuous data were presented as mean ± standard deviation, the data were compared using independent t test (χ2);
  3. bThe categorical data were presented as numbers (frequencies, %), Chi-square test was used for categorical data (F);
  4. cn (male) / n (female);
  5. eThe non-normal distribution continuous data were presented as median (interquartile range), the data were compared using analysis of variance (F);
  6. d1Statistically significant when BTCP compared to OTCP (P < 0.05);
  7. d2Statistically significant when BTCP compared to UTCP (P < 0.05);
  8. d3Statistically significant when OTCP compared to UTCP (P < 0.05);
  9. f1Not statistically significant when BTCP compared to OTCP (P>0.05);
  10. f2Not statistically significant when BTCP compared to UTCP (P>0.05);
  11. f3Not statistically significant when OTCP compared to UTCP (P>0.05)
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BMC Public Health

ISSN: 1471-2458

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