Former winner of TV show Alone Australia Gina Chick was diagnosed with breast cancer just days after finding out she was pregnant. She describes in her recent book her experience with chemotherapy and what followed. Thankfully, cancer diagnoses during pregnancy and in the year following the birth are rare.

But such cases are becoming more common in parts of the world , including Australia . Researchers aren’t exactly sure why. Here’s what researchers know so far, and the options for treatment.

How rare is it? A New South Wales study found that in 1994 there were about 94 cancer diagnoses during pregnancy or within one year of birth per 100,000 women giving birth. That rose to about 163 per 100,000 in 2013. Although these statistics are more than ten years old, these are the most recent and rigorous data available in Australia.

A 2023 Swedish study of pregnancies in 1973-2017 had similar findings. Both studies found about one-quarter of pregnancy-associated cancers are diagnosed before birth, with the rest diagnosed in the year after birth. What type of cancers are we talking about? The United Kingdom’s first comprehensive assessment of cancer during pregnancy looked at diagnoses in 2016-2020.

This study, the NSW study, and others, have found breast and skin cancers (often melanoma) were the most common pregnancy-associated cancers. There were also high rates of thyroid, gynaecological (particularly cervical and ovarian) and blood cancers in this group. The UK study foun.