Variables | Infants | Birth defects | Unadjusted OR (95%CI) | ||
---|---|---|---|---|---|
n | Proportion in total (%) | n | Prevalence (%, 95%CI) | ||
Sex | Â | Â | Â | Â | Â |
 Female | 67,809 | 47.38 | 1130 | 16.66(15.69–17.64) | Reference |
 Male | 75,305 | 52.62 | 1852 | 24.59(23.47–25.71) | 1.49(1.38–1.60) |
 Unknown | 4 | < 0.01 | 2 | - | - |
Residence | Â | Â | Â | Â | Â |
 Urban | 47,777 | 33.38 | 985 | 20.62(19.33–21.90) | Reference |
 Rural | 95,341 | 66.62 | 1999 | 20.97(20.05–21.89) | 1.02(0.94–1.10) |
Number of births | Â | Â | Â | Â | Â |
 Singleton | 139,557 | 97.51 | 2880 | 20.64(19.88–21.39) | Reference |
 Multiple births | 3561 | 2.49 | 104 | 29.21(23.59–34.82) | 1.43(1.17–1.74) |
Paternal age (years old) | Â | Â | Â | Â | Â |
 25–29 | 51,332 | 35.87 | 1172 | 22.83(21.52–24.14) | Reference |
 < 20 | 267 | 0.19 | 12 | 44.94(19.51–70.37) | 2.01(1.13–3.60) |
 20–24 | 6928 | 4.84 | 235 | 33.92(29.58–38.26) | 1.50(1.30–1.73) |
 30–34 | 50,809 | 35.50 | 887 | 17.46(16.31–18.61) | 0.76(0.70–0.83) |
 >=35 | 33,782 | 23.60 | 678 | 20.07(18.56–21.58) | 0.88(0.80–0.96) |
Maternal age (years old) | Â | Â | Â | Â | Â |
 25–29 | 62,406 | 43.60 | 1260 | 20.19(19.08–21.31) | Reference |
 < 20 | 2328 | 1.63 | 66 | 28.35(21.51–35.19) | 1.42(1.10–1.82) |
 20–24 | 24,523 | 17.13 | 537 | 21.90(20.05–23.75) | 1.09(0.98–1.20) |
 30–34 | 38,391 | 26.82 | 741 | 19.30(17.91–20.69) | 0.96(0.87–1.05) |
 >=35 | 15,470 | 10.81 | 380 | 24.56(22.09–27.03) | 1.22(1.09–1.37) |
Number of pregnancies (times) | Â | Â | Â | Â | Â |
 1 | 48,541 | 33.92 | 1043 | 21.49(20.18–22.79) | Reference |
 2 | 57,947 | 40.49 | 1157 | 19.97(18.82–21.12) | 0.93(0.85–1.01) |
 3 | 20,995 | 14.67 | 446 | 21.24(19.27–23.21) | 0.99(0.88–1.11) |
 >=4 | 15,635 | 10.92 | 338 | 21.62(19.31–23.92) | 1.01(0.89–1.14) |
Parity (times) | Â | Â | Â | Â | Â |
 1 | 60,271 | 42.11 | 1320 | 21.90(20.72–23.08) | Reference |
 2 | 75,934 | 53.06 | 1516 | 19.96(18.96–20.97) | 0.91(0.84–0.98) |
 >=3 | 6913 | 4.83 | 148 | 21.41(17.96–24.86) | 0.98(0.82–1.16) |
Maternal household registration | Â | Â | Â | Â | Â |
 Local | 141,546 | 98.90 | 2892 | 20.43(19.69–21.18) | Reference |
 Non-local | 1572 | 1.10 | 92 | 58.52(46.57–70.48) | 2.98(2.41–3.69) |
Total | 143,118 | 100.00 | 2984 | 20.85(20.10–21.60) |  |