Table 3. Association of stillbirth with categories of maternal pre-pregnancy body mass index by gestational age, race-ethnicity and parity, California 2007–2010. 1 .
| BMI | 20–23 weeks | 24–27 weeks | 28–31 weeks | 32–36 weeks | 37–41 weeks | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| N | RR (CI) | N | RR (CI) | N | RR (CI) | N | RR (CI) | N | RR (CI) | ||
| Nulliparous | |||||||||||
| Non-Hispanic White | Normal | 78 | ref | 46 | ref | 36 | ref | 65 | ref | 78 | ref |
| Overweight | 28 | 1.06 (0.68,1.63) | 22 | 1.49 (0.89,2.47) | 18 | 1.54 (0.87,2.72) | 26 | 1.26 (0.80,1.99) | 32 | 1.25 (0.83,1.89) | |
| Obese I | 24 | 2.28 (1.44,3.61) | 4 | 0.74 (0.26,2.05) | 13 | 2.98 (1.57,5.65) | 11 | 1.47 (0.77,2.80) | 28 | 2.92 (1.89,4.52) | |
| Obese II | 8 | 1.91 (0.92,3.96) | 4 | 1.92 (0.69,5.37) | 4 | 2.42 (0.85,6.83) | 6 | 2.10 (0.90,4.86) | 6 | 1.63 (0.71,3.76) | |
| Obese III | 10 | 4.46 (2.29,8.66) | 2 | – | 2 | – | 1 | – | 5 | 2.70 (1.09,6.69) | |
| Non-Hispanic Black | Normal | 34 | ref | 19 | ref | 16 | ref | 17 | ref | 18 | ref |
| Overweight | 21 | 1.26 (0.73,2.17) | 12 | 1.31 (0.63,2.71) | 8 | 1.14 (0.49,2.67) | 17 | 2.11 (1.07,4.13) | 9 | 1.03 (0.46,2.30) | |
| Obese I | 13 | 1.67 (0.88,3.17) | 4 | 0.95 (0.32,2.79) | 3 | 0.98 (0.28,3.37) | 5 | 1.39 (0.51,3.78) | 6 | 1.55 (0.61,3.92) | |
| Obese II | 10 | 2.73 (1.34,5.57) | 6 | 3.12 (1.23,7.89) | 2 | – | 2 | – | 2 | – | |
| Obese III | 6 | 2.36 (0.98,5.66) | 0 | – | 4 | 4.97 (1.63,15.1) | 4 | 3.88 (1.30,11.7) | 3 | 2.65 (0.77,9.09) | |
| Hispanic | Normal | 105 | ref | 67 | ref | 61 | ref | 84 | ref | 85 | ref |
| Overweight | 103 | 2.02 (1.54,2.66) | 35 | 1.12 (0.74,1.68) | 29 | 1.01 (0.65,1.58) | 56 | 1.45 (1.03,2.03) | 50 | 1.23 (0.87,1.75) | |
| Obese I | 63 | 2.96 (2.16,4.05) | 12 | 0.95 (0.52,1.77) | 8 | 0.69 (0.33,1.44) | 16 | 1.02 (0.60,1.75) | 23 | 1.39 (0.87,2.20) | |
| Obese II | 23 | 3.12 (1.98,4.92) | 5 | 1.20 (0.48,2.98) | 5 | 1.28 (0.51,3.21) | 4 | 0.78 (0.28,2.12) | 9 | 1.60 (0.80,3.18) | |
| Obese III | 22 | 6.09 (3.83,9.69) | 4 | 2.05 (0.74,5.65) | 2 | – | 3 | 1.25 (0.40,3.98) | 9 | 3.35 (1.68,6.69) | |
| Multiparous | |||||||||||
| Non-Hispanic White | Normal | 67 | ref | 45 | ref | 34 | ref | 61 | ref | 61 | ref |
| Overweight | 38 | 1.27 (0.85,1.89) | 29 | 1.54 (0.96,2.47) | 21 | 1.43 (0.83,2.47) | 29 | 1.03 (0.66,1.61) | 54 | 2.11 (1.46,3.05) | |
| Obese I | 20 | 1.44 (0.87,2.39) | 10 | 1.22 (0.61,2.44) | 16 | 2.43 (1.33,4.45) | 14 | 1.07 (0.60,1.92) | 20 | 1.79 (1.07,2.98) | |
| Obese II | 12 | 1.96 (1.05,3.65) | 10 | 2.87 (1.43,5.75) | 6 | 2.14 (0.89,5.15) | 16 | 2.82 (1.61,4.92) | 15 | 3.14 (1.77,5.57) | |
| Obese III | 7 | 1.93 (0.88,4.23) | 9 | 4.62 (2.23,9.58) | 4 | 2.51 (0.88,7.16) | 5 | 1.52 (0.61,3.79) | 2 | – | |
| Non-Hispanic Black | Normal | 22 | ref | 13 | ref | 15 | ref | 20 | ref | 13 | ref |
| Overweight | 19 | 1.13 (0.61,2.10) | 15 | 1.64 (0.78,3.45) | 11 | 1.03 (0.47,2.26) | 16 | 1.12 (0.58,2.16) | 10 | 1.10 (0.48,2.50) | |
| Obese I | 15 | 1.56 (0.81,3.02) | 5 | 1.00 (0.36,2.81) | 7 | 1.21 (0.49,2.97) | 15 | 1.91 (0.97,3.74) | 14 | 2.83 (1.33,6.05) | |
| Obese II | 10 | 2.09 (0.99,4.42) | 8 | 3.23 (1.33,7.82) | 4 | 1.41 (0.47,4.26) | 3 | 0.78 (0.23,2.65) | 2 | – | |
| Obese III | 7 | 1.89 (0.81,4.44) | 1 | – | 2 | – | 5 | 1.77 (0.66,4.74) | 3 | 1.71 (0.48,6.01) | |
| Hispanic | Normal | 124 | ref | 70 | ref | 78 | ref | 144 | ref | 126 | ref |
| Overweight | 132 | 1.22 (0.95,1.56) | 63 | 1.09 (0.77,1.53) | 56 | 0.87 (0.62,1.23) | 112 | 0.92 (0.72,1.18) | 134 | 1.28 (1.00,1.63) | |
| Obese I | 78 | 1.34 (1.01,1.79) | 37 | 1.26 (0.85,1.88) | 42 | 1.28 (0.88,1.87) | 50 | 0.81 (0.59,1.12) | 67 | 1.26 (0.93,1.69) | |
| Obese II | 32 | 1.49 (1.01,2.20) | 13 | 1.24 (0.68,2.24) | 14 | 1.23 (0.70,2.18) | 16 | 0.75 (0.45,1.26) | 26 | 1.40 (0.92,2.13) | |
| Obese III | 23 | 2.09 (1.34,3.27) | 0 | – | 4 | 0.73 (0.27,2.00) | 12 | 1.18 (0.65,2.12) | 18 | 2.00 (1.22,3.28) | |
1 Relative Risks (RR) reflect estimated risk of stillbirth relative to term (37–41 weeks) live birth adjusted for maternal age, education, and height; excludes women with gestational or pre-gestational diabetes or pregnancy-induced or chronic hypertension with one exception. For estimates among stillbirth at 20–23 weeks, the comparison group of term live births included the following additional births beyond those shown in Table 1 who had gestational diabetes: non-Hispanic White (n = 386,490), non-Hispanic Black (n = 69,633), and Hispanic (n = 734,548). RRs were not calculated for cells with fewer than 3 cases.