Pregnant mothers are using pictures of their 'rainbow babies' to spread awareness of miscarriages / CLAUDIO SANTANA/AFP/GettyImages

Miscarriages occur in 15 to 20% of pregnancies, but a lot of people never talk about them

Mothers from all over the world are sharing pictures of their 'rainbow babies' - and spreading awareness of the often unspoken pain that follows a miscarriage.

The term 'rainbow baby' refers to the sky after a period of rough weather - after the chaotic storm of a miscarriage or the loss of a child, a rainbow in the form of a child often breaks through the clouds. So when a women has a child after suffering a miscarriage, that child is a 'rainbow baby'.

One particularly popular image, posted on the Every Child is a Blessing Facebook page, shows seven pregnant women who have suffered miscarriages dressed in the colours of the rainbow. The second part of the picture, taken some months later, shows the mothers with their healthy children - and this time, it's the kids who are wearing the colours.

Miscarriages, especially when they occur in the early stages of pregnancy, are often never spoken about in public - leaving the grieving parents to cope with the pain silently.

Who loves this "rainbow babies" photo? A “rainbow baby” is a baby that is born following a miscarriage, stillbirth,...

Posted by Every Child is a Blessing: The Journey Through My Pregnancy on Sunday, 20 September 2015

Fortunately, this seems to be changing, through parents having the courage to speak out about their experiences.

In July, Facebook co-founder Mark Zuckerberg announced that he and his wife were expecting a child in a post on the social network.

The couple also openly spoke about their three previous miscarriages, saying they were "lonely experiences."

"You feel so hopeful when you learn you're going to have a child," Zuckerberg wrote.

"You start imagining who they'll become and dreaming of hopes for their future. You start making plans, and then they're gone."

He added: "We hope that sharing out experience will five more people the same hope we felt and will help more people feel comfortable sharing their stories as well."

In the UK, miscarriage occurs in 15 to 20 per cent of pregnancies, and only 15 per cent of women who have miscarried feel they were given the right support and information. With any luck, posts about 'rainbow babies' on social media will help encourage more parents to talk openly about their feelings in the aftermath of a miscarriage.