'There is a high chance of two happy outcomes'
It is estimated that one pregnant woman in every 1,000 will be diagnosed with cancer.
Because age is the most significant risk factor for the disease, the rate of cancer during pregnancy may be increasing as more women are waiting until they are older to have children.
Although it is a challenging journey, many women have found solutions and survived.
When making treatment decisions for cancer during pregnancy, doctors consider treatment options for the mother and risks to the foetus.
Consultant oncologist, Professor John Crown explained that if somebody had a "surgically removable cancer that was life-threatening" and for which treatment delay would be a risk, surgery would be expedited.
The rule of thumb with chemotherapy is to begin it after three months of pregnancy.
"Chemotherapy in the first trimester can be catastrophic," he said. "After the second trimester, the incidence of foetal malformations is not depreciably increased, although the incidence of stillbirth is higher."
He stressed radiotherapy, which would radiate the foetus, was "a no-no".
"At any stage in pregnancy you would desperately try to avoid it. I can think of only one circumstance in all of my 30 years where we have had to make a very tough decision to recommend that a woman would undertake radiotherapy which would radiate the foetus," he said.
In the most common case of breast cancer, he said that most early-diagnosed cases were potentially curable.
"What I say to most patients is, 'I know this sounds like the worst thing that could happen but there is a high chance you are going to get two happy outcomes here: you will be cured and the baby will be born normal. That is the most likely outcome'."
Professor Crown praised the courage of the women who find themselves pregnant and with cancer.
"It is always a huge inspiration to us; I find they are very protective of their child. They do understand that unless the mother is cured, the baby can't live," he said.