Table 2.
Diagnosis- and treatment-related factors associated with time to pregnancy according to five different models: (1) type of diagnosis; (2) age at diagnosis; (3) CED score; (4) radiotherapy site; (5) stem cell transplantation
| Total number of pregnancies | Time to pregnancy (months); Median (IQR) | Ratio (95% CI) | |
|---|---|---|---|
| Controls | 787 | 3.0 (1.0–7.5) | Ref. |
| Survivors | 721 | 3.0 (1.0–8.0) | 1.1 (1.0–1.2)a |
| Model 1: type of diagnosisa | |||
| Controls | 787 | 3.0 (1.0–7.5) | Ref. |
| Leukaemia | 236 | 3.0 (1.0–7.3) | 1.1 (0.9–1.2) |
| Lymphoma | 164 | 3.0 (1.0–8.0) | 1.1 (0.9–1.4) |
| CNS tumours | 27 | 7.0 (3.0–12.0) | 2.0 (1.3–3.0) |
| Neuroblastoma and other peripheral nervous cell tumours | 60 | 3.5 (1.3–9.0) | 1.0 (0.8–1.3) |
| Renal tumours | 66 | 3.5 (1.4–12.0) | 1.3 (1.0–1.8) |
| Bone tumours | 72 | 3.0 (2.0–5.8) | 1.0 (0.8–1.3) |
| Soft tissue sarcoma | 49 | 3.0 (1.8–6.0) | 0.9 (0.7–1.2) |
| Germ cell tumours | 24 | 2.0 (1.0–3.8) | 0.9 (0.5–1.5) |
| Other | 23 | 4.0 (2.0–9.0) | 1.3 (0.8–1.9) |
| Model 2: age at diagnosis (years)a | |||
| Controls | 787 | 3.0 (1.0–7.5) | Ref. |
| < 10 | 408 | 3.0 (1.5–9.0) | 1.1 (1.0–1.3) |
| ≥ 10 to < 13 | 120 | 3.0 (1.0–8.8) | 1.1 (0.9–1.4) |
| ≥ 13 | 193 | 3.0 (1.0–7.5) | 1.1 (0.9–1.3) |
| Model 3: CED scoreb | |||
| Controls | 787 | 3.0 (1.0–7.5) | Ref. |
| 0 | 354 | 3.0 (1.0–9.0) | 1.1 (0.9–1.2) |
| > 0 to ≤ 4000 mg/m2 | 100 | 3.0 (1.0–7.0) | 1.0 (0.8–1.3) |
| > 4000 to ≤ 8000 mg/m2 | 104 | 4.0 (1.3–8.0) | 1.1 (0.9–1.4) |
| > 8000 mg/m2 | 142 | 3.0 (2.0–8.0) | 1.1 (0.9–1.4) |
| Model 4: radiotherapy body sitec | |||
| Controls | 787 | 3.0 (1.0–7.5) | Ref. |
| No RT | 377 | 3.0 (1.0–7.0) | 1.0 (0.9–1.2) |
| Cranial/spinal RT | 161 | 4.0 (1.0–9.0) | 1.2 (0.9–1.5) |
| Low dose (< 20 Gy) | 47 | 3.0 (1.0–7.0) | 1.2 (0.7–2.0) |
| Medium dose (20–30 Gy) | 73 | 4.0 (2.0–12.0) | 1.3 (0.9–1.8) |
| High dose (≥ 30 Gy) | 38 | 6.0 (1.0–9.8) | 1.3 (0.8–2.1) |
| Lower abdominal/pelvic RT | 64 | 4.8 (2.0–10.5) | 1.3 (1.0–1.8) |
| Low dose (< 20 Gy) | 26 | 6.5 (2.0–14.5) | 1.7 (0.9–2.9) |
| Medium dose (20–30 Gy) | 15 | 3.0 (0.0–6.0) | 1.0 (0.6–1.9) |
| High dose (≥ 30 Gy) | 23 | 5.0 (3.0–12.0) | 1.5 (1.0–2.4) |
| TBI | 7 | 5.0 (4.0–10.0) | 1.2 (0.5–2.7) |
| Other RT | 104 | 3.0 (2.0–6.0) | 1.0 (0.8–1.3) |
| Model 5: stem cell transplantationa | |||
| Controls | 787 | 3.0 (1.0–7.5) | Ref. |
| No | 696 | 3.0 (1.0–8.0) | 1.1 (1.0–1.2) |
| Yes | 14 | 4.8 (0.8–10.5) | 1.2 (0.6–2.3) |
CED cyclophosphamide equivalent dose, CNS central nervous system, RT radiotherapy, TBI total body irradiation
aCorrected for age at time of pregnancy and educational level
bCorrected for age at time of pregnancy, educational level, and gonadotoxic radiotherapy (i.e. lower abdominal/pelvic RT and/or TBI) (yes or no)
cCorrected for age at time of pregnancy, educational level and alkylating agent therapy (yes or no)