Table 2 The trend of SRB in the subgroups of maternal age at three stages of Two-Child Policy (22 Hospitals in Hebei Province of China, 2013–2017)
From: How does the two-child policy affect the sex ratio at birth in China? A cross-sectional study
SRB in subgroup | BTCP | OTCP | UTCP | P |
|---|---|---|---|---|
< 20 years (SRB) | 1.012 | 1.083 | 1.016 | 0.95 |
20–24 years (SRB) | 1.079 | 1.049 | 1.012 b2 | < 0.01 |
25–29 years (SRB) | 1.079 | 1.058 | 1.054 b2 | 0.06 |
30–34 years (SRB) | 1.110 | 1.049 b1 | 1.049 b2 | 0.01 |
≥35 years (SRB) | 1.146 | 1.016 b1 | 1.062 b2 | 0.10 |
Unadjusted OR (95% CI) | ||||
  < 20 years | 1.00 | 1.07(0.91–1.25) | 1.01(0.86–1.17) | 0.67 |
 20–24 years | 1.00 | 0.97(0.93–1.01) | 0.94(0.89–0.98) | < 0.01 |
 25–29 years | 1.00 | 0.98(0.95–1.01) | 0.97(0.95–1.00) | 0.13 |
 30–34 years | 1.00 | 0.95(0.91–0.99) | 0.95(0.91–0.98) | 0.02 |
  ≥ 35 years | 1.00 | 0.80(0.82–0.95) | 0.93(0.87–0.99) | < 0.01 |
Adjusted OR (95% CI) | ||||
  < 20 years | 1.00 | 1.08(0.92–1.26) | 1.02(0.87–1.19) | 0.65 |
 20–24 years | 1.00 | 0.98(0.94–1.02) | 0.94(0.90–0.98) | 0.01 |
 25–29 years | 1.00 | 0.98(0.95–1.01) | 0.97(0.95–0.99) | 0.12 |
 30–34 years | 1.00 | 0.94 (0.90–0.99) | 0.94(0.90–0.98) | < 0.01 |
  ≥ 35 years | 1.00 | 0.89(0.82–0.96) | 0.93(0.87–0.99) | < 0.01 |