They say life is full of surprises, and one Welshman has had the surprise of his life.
When Gareth William's girlfriend, Rhiannon, started screaming out with severe stomach pain, he did the right thing and called for an ambulance.
He told the operator it was almost as if his girlfriend was giving birth, but she wasn't pregnant.
"I had to carry her from the bathroom to the bedroom, and that's when I could see that something strange was happening," he told the BBC.
"I called 999 and I told them there was something seriously wrong with my girlfriend."
A recording of the emergency call captures his bewilderment.
"She's in a lot of pain. It's like she's trying to give birth to something but she's not pregnant," he told the call handler.
"She's actually got this large lump coming out; it's just coming out. She's not pregnant."
But within minutes Rhiannon had actually given birth to a healthy baby boy.
"It was a huge shock because we had absolutely no idea that she was pregnant, but we're over the moon," Mr Williams says.