表1 月別にみた出生率（人口千対） −平成元〜12年−
| 平成元年 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
| 総数 | 10.2 | 10.0 | 9.9 | 9.8 | 9.6 | 10.0 | 9.6 | 9.7 | 9.5 | 9.6 | 9.4 | 9.5 |
| 1月 | 10.2 | 10.0 | 9.7 | 9.6 | 9.5 | 9.6 | 9.7 | 9.4 | 9.5 | 9.4 | 9.4 | 9.5 |
| 2月 | 10.1 | 9.8 | 9.7 | 9.5 | 9.4 | 9.7 | 9.5 | 9.4 | 9.2 | 9.3 | 9.3 | 9.4 |
| 3月 | 9.9 | 9.7 | 9.6 | 9.3 | 9.4 | 9.6 | 9.3 | 9.2 | 9.1 | 9.3 | 9.1 | 9.3 |
| 4月 | 10.1 | 9.9 | 9.7 | 9.7 | 9.5 | 9.8 | 9.4 | 9.6 | 9.3 | 9.6 | 9.5 | 9.2 |
| 5月 | 10.3 | 10.2 | 10.0 | 9.9 | 9.7 | 10.0 | 9.6 | 9.9 | 9.9 | 9.6 | 9.4 | 9.4 |
| 6月 | 10.0 | 9.9 | 9.9 | 10.0 | 9.8 | 10.0 | 9.8 | 9.8 | 9.8 | 9.8 | 9.5 | 9.3 |
| 7月 | 10.4 | 10.3 | 10.3 | 10.4 | 10.0 | 10.4 | 10.0 | 10.2 | 10.1 | 10.2 | 9.7 | 9.7 |
| 8月 | 10.5 | 10.3 | 10.2 | 10.0 | 9.9 | 10.4 | 10.0 | 9.9 | 9.8 | 9.9 | 9.7 | 9.8 |
| 9月 | 10.3 | 10.1 | 10.3 | 10.4 | 9.9 | 10.4 | 9.9 | 10.1 | 9.7 | 10.2 | 9.7 | 10.0 |
| 10月 | 10.1 | 9.9 | 10.2 | 9.8 | 9.2 | 10.1 | 9.1 | 9.9 | 9.5 | 9.5 | 9.0 | 9.5 |
| 11月 | 10.1 | 9.6 | 9.7 | 9.4 | 9.3 | 9.9 | 9.1 | 9.5 | 9.2 | 9.1 | 9.1 | 9.4 |
| 12月 | 10.3 | 9.8 | 9.9 | 9.6 | 9.5 | 9.9 | 9.2 | 9.4 | 9.4 | 9.4 | 9.2 | 9.3 |