Demographic characteristics of the sample, by interpregnancy interval (IPI)
| IPI duration (months) | Mother's age at miscarriage at beginning of IPI (SD) | Mother's age at outcome at end of IPI (SD) | MCH-FP area (%) | Woman has no education (%)* | Gravida=2 (%) | Year | |||
|---|---|---|---|---|---|---|---|---|---|
| 1977–1990 (%) | 1991–2000 (%) | 2001–2008 (%) | n | ||||||
| ≤3 | 24.9 (5.8) | 25.6 (5.8) | 44.3 | 51.0 | 27.7 | 46.3 | 25.1 | 28.6 | 2138 |
| 3–6 | 25.5 (6.1) | 26.5 (6.0) | 45.1 | 54.0 | 23.8 | 50.2 | 25.3 | 24.6 | 2458 |
| ≤6 | 25.2 (6.0) | 26.1 (6.0) | 44.7 | 52.6 | 25.6 | 48.3 | 25.1 | 26.5 | 4596 |
| 6–12 | 25.9 (6.4) | 27.2 (6.4) | 43.4 | 53.8 | 24.4 | 48.0 | 27.8 | 24.1 | 2920 |
| 12–18 | 26.7 (6.7) | 28.5 (6.7) | 45.9 | 51.1 | 21.3 | 44.5 | 27.3 | 28.1 | 988 |
| 18–24 | 26.9 (6.8) | 29.2 (6.7) | 46.8 | 50.3 | 21.0 | 37.9 | 30.5 | 31.7 | 676 |
| >24 | 27.0 (6.5) | 31.5 (6.5) | 46.7 | 50.0 | 17.4 | 29.9 | 34.3 | 35.8 | 1255 |
| 24–36 | 27.4 (6.8) | 30.5 (6.7) | 46.6 | 50.3 | 17.4 | 33.2 | 32.3 | 34.5 | 579 |
| 36–48 | 27.0 (6.5) | 31.1 (6.4) | 48.6 | 45.9 | 18.8 | 33.2 | 29.8 | 37.0 | 292 |
| >48 | 26.5 (6.0) | 33.4 (6.0) | 45.3 | 52.6 | 16.2 | 22.4 | 40.9 | 36.7 | 384 |
| Total | 25.9 (6.3) | 27.5 (6.5) | 44.8 | 52.4 | 23.5 | 45.0 | 27.6 | 27.4 | 10 435 |
| Significance of differences across expanded IPI categories | |||||||||
| p<0.001 | p<0.001 | ns | p=0.064 | p<0.001 | p<0.001 | p<0.001 | p<0.001 | ||
*Among those with non-missing values. Education is not reported for 347 cases.
MCH-FP, Maternal Child Heath-Family Planning; ns, not significant.