One mother has said she was denied time with her new baby, as she was undergoing chemotherapy following her son's birth.
Mary was speaking amid a fresh push for separation between maternity leave and sick leave for new mothers.
Every year in Ireland, 60 women go through a cancer diagnosis while pregnant or postpartum.
The Irish Cancer Society has said these women are unable to defer their maternity leave when ill, so all or almost all of their maternity leave is spent receiving life-saving treatment.
Mary was diagnosed with breast cancer when she was nine weeks pregnant with her first child.
She told Lunchtime Live something needs to change.
"I went through a lot of treatment while I was pregnant, but actually six weeks after I had my son Killian I still had a lot more treatment to do," she said.
"I ended up having another three months of chemo after he was born, and then I ended up having a lot of surgeries.
"All of this treatment and everything that I had to go through to try and get myself well happened on my maternity leave.
"So that whole period of my life was consumed with treatment, going to hospital, staying in hospital, and wasn't really about my time with Killian, bonding with Killian, looking after him.
"I suppose I really feel like I was really denied something that was fundamentally so important".
Mary said if this had happened while she wasn't pregnant, she would have been out on sick leave.
"Once you have your baby it's maternity leave; even though you're still sick, even though it's still sick leave, you can't continue on sick leave at that time.
"It's just crazy that even though you are sick, it's immediately just moved into maternity leave for six months and the sick leave is not used then.
"For paternity leave, if a father is unwell, he then can take his sick leave and defer the paternity leave until he's better and then... have that time with his child.
"We don't really understand why women of Ireland aren't afforded that same right?
"If we're sick can we not just take our sick leave - we're not asking for anything extra.
"It's just can we take our sick leave and then, when we're better, have that maternity leave and have that time".
Mary has said she is hopeful of change.
"Every week that goes by, there's another woman who's going to be affected by this," she said.
"There's a lot of people listening to this who know that it's wrong.
"If they really feel that this is so unjust, which it is, I would just plead to them to contact their local TDs and tell them about the campaign.
"The more people that get behind us, the greater the chance is that there will actually be real change," she added.
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