Many people diagnosed with haematological malignancies or who undergo a haematopoietic stem-cell transplantation (HSCT) must face the impact of their treatment on their future fertility. A new German registry study provides insight into the likelihood of pregnancy and live birth in 2654 women aged 18–40 years who had had an allogeneic HSCT to treat a range of conditions. 50 women had 74 pregnancies, and the annual first birth rate in recipients of an HSCT was 6-times lower than that of the general population at 0·45% (95% CI 0·31–0·59); however, 39 (72%) of 54 pregnancies occurred spontaneously without the need for assistive reproductive technology, providing evidence that pregnancy is possible after this treatment.