Family size and duration of fertility in female cancer survivors: a population-based analysis.

Objective: To assess family size and timescale for achieving pregnancy in women who remain fertile after cancer.

Design: Population-based analysis.

Setting: National databases.

Patient(s): All women diagnosed with cancer before the age of 40 years in Scotland, 1981-2012 (n = 10,267) with no previous pregnancy; each was matched with 3 population controls.

Intervention(s): None.

Main Outcome Measure(s): The number and timing of pregnancy and live birth after cancer diagnosis, to 2018.

Result(s): In 10,267 cancer survivors, the hazard ratio for a subsequent live birth was 0.56 (95% confidence interval, 0.53-0.58) overall. In women who achieved a subsequent pregnancy, age at live birth increased (mean ± SD, 31.2 ± 5.5 vs. 29.7 ± 6.1 in controls), and the family size was lower (2.0 ± 0.8 vs. 2.3 ± 1.1 live births). These findings were consistent across several diagnoses. The interval from diagnosis to last pregnancy was similar to that of controls (10.7 ± 6.4 vs. 10.9 ± 7.3 years) or significantly increased, for example, after breast cancer (6.2 ± 2.8 vs. 5.3 ± 3.3 years) and Hodgkin lymphoma (11.1 ± 5.1 vs. 10.1 ± 5.8 years).

Conclusion(s): These data quantify the reduced chance of live birth after cancer. Women who subsequently conceived achieved a smaller family size than matched controls, but the period of time after cancer diagnosis across which pregnancies occurred was similar or, indeed, increased. Thus, we did not find evidence that women who were able to achieve a pregnancy after cancer had a shorter timescale over which they have pregnancies.