Women with a history of breast cancer are significantly less likely than the general population to get pregnant, according to a new meta-analysis presented at the San Antonio Breast Cancer Symposium.

But although there is some higher risk for poorer foetal outcomes, they often have healthy babies and good long-term health.

“Returning to a normal life after cancer should be considered as a crucial ambition in cancer care in the 21st century,” said Dr Eva Blondeaux, of Ospedale Policlinico San Martino in Genova, Italy, who presented the results.

“Pregnancy after breast cancer diagnosis and treatment is a priority for many young survivors.”

The new meta-analysis included a total of 39 studies, covering more than 100,000 women with breast cancer. It found that compared with the general population, survivors of breast cancer had a relative risk of pregnancy of 0.40 (95% CI, 0.32-0.49; p<0.001), meaning they had a 60% reduced chance of becoming pregnant.

When compared with other cancers, only women with cervical cancer were less likely to get pregnant, with an RR of 0.33. Among all cancer patients, the RR was 0.65.

There were no differences with regard to the likelihood of a completed pregnancy, or of spontaneous or induced abortion. There was a higher risk of undergoing a Caesarean section in those with a history of breast cancer, with an RR of 1.14 (95% CI, 1.04-1.25; p=0.007).

There were also some differences with regard to foetal outcomes, with a higher likelihood of low birth weight (RR 1.50), of preterm birth (RR, 1.45), and of being small for gestational age (RR, 1.16). There was no significant difference with regard to the risk for congenital abnormalities.

The differences in foetal outcomes appeared largely confined to women who had received prior chemotherapy, with no differences seen in those who did not.

The results regarding maternal safety were reassuring, with pregnancy showing no detrimental effect on survival compared with breast cancer patients who did not become pregnant. In fact, hazard ratios for disease-free and overall survival favoured the women who became pregnant.

“The higher risk of delivery and foetal complications particularly in women exposed to prior chemotherapy, calls for ensuring a closer monitoring of these pregnancies,” Dr Blondeaux said.

The study’s senior author Dr Matteo Lambertini said that the results highlight the need for clinicians to consider pregnancy desires as a crucial component of a survivorship care plan. “This starts with offering oncofertility counselling to all newly diagnosed young breast cancer patients,” he said.

Disclosure statement: Dr Blondeaux reports no conflicts of interest or financial disclosures. Dr Lambertini has received speaker fees from and acted as a consultant for several pharmaceutical companies.