Trends by birthweight group for the whole city (58 552 live singleton births) 1985–94
| Year | Mean birthweight (SE) | <1500 g % (No) | 1500–999 g % (No) | 2000–499 g % (No) | 2500–999 g % (No) | 3000–499 g % (No) | ⩾3500 g % (No) |
|---|---|---|---|---|---|---|---|
| 1985 (n=5866) | 3287 | 1.04 (61) | 1.53 (90) | 4.84 (284) | 17.64 (1035) | 38.61 (2265) | 36.32 (2131) |
| 1986 (n=6137) | 3286 | 1.08 (66) | 1.53 (94) | 4.90 (300) | 18.01 (1105) | 38.16 (2342) | 36.34 (2230) |
| 1987 (n=6127) | 3306 | 0.88 (54) | 1.47 (90) | 4.59 (281) | 16.86 (1033) | 38.40 (2353) | 37.80 (2316) |
| 1988 (n=5679) | 3326 | 1.09 (62) | 1.29 (73) | 4.40 (250) | 16.66 (946) | 37.35 (2121) | 39.21 (2227) |
| 1989 (n=5469) | 3292 | 1.19 (65) | 1.23 (67) | 4.64 (254) | 17.86 (977) | 38.27 (2093) | 36.81 (2013) |
| 1985–9 | 3299 | 1.05 (308) | 1.41 (414) | 4.67 (1369) | 17.40 (5096) | 38.17 (11174) | 37.29 (10917) |
| 1990 (n=5513) | 3296 | 1.09 (60) | 1.31 (72) | 4.84 (267) | 17.88 (986) | 37.75 (2081) | 37.13 (2047) |
| 1991 (n=5683) | 3304 | 0.84 (48) | 1.44 (82) | 4.82 (274) | 18.18 (1033) | 36.97 (2101) | 37.74 (2145) |
| 1992 (n=5969) | 3311 | 0.95 (57) | 1.68 (100) | 5.28 (315) | 16.97 (1013) | 36.27 (2165) | 38.85 (2319) |
| 1993 (n=6134) | 3336 | 1.17 (72) | 1.37 (84) | 4.84 (297) | 16.92 (1038) | 34.48 (2115) | 41.21 (2528) |
| 1994 (n=5970) | 3321 | 1.54 (92) | 1.32 (79) | 4.71 (281) | 16.35 (976) | 36.43 (2175) | 39.65 (2367) |
| 1990–4 | 3315 | 1.12 (329) | 1.42 (417) | 4.90 (1434) | 17.24 (5046) | 36.34 (10637) | 38.97 (11406) |
| χ2 for linear trend | 3.88 | 0.29 | 0.67 | 2.92 | 26.18 | 33.38 | |
| p Value | <0.05 | >0.50 (NS) | >0.10 (NS) | >0.10 (NS) | <0.0001 | <0.0001 |