Hannah's mother Michelle Browne is calling for all pregnant women to have a scan for Peripartum cardiomyopathy - the rare heart condition which killed her daughter.
She said: "if I can save one person out of all of this, it would mean so much, because then they wouldn't have to go through the heartache that we have had to go through as a family."
She said all is needed is "a simple scan - that would cost about £40-£60 - that would pick it up."
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Road closures are in place until 3pm today as the Cardiff Triathlon gets underway in Cardiff Bay.
It is going to stay fine and dry through the night with light winds.
It is going to stay fine and dry throughout.