Anna Faris has opened up about the terrifying experience she had while she was pregnant with her five-year-old son, Jack, who she shares with former husband Chris Patt. The former couple separated in August this year.

In her new memoir, Unqualified, the Scary Movie star has revealed how suddenly things changed after facing no problems throughout the first 30 weeks of her pregnancy. During the pregnancy, she was 35 years old.

Faris was admitted to hospital after her water broke even though she wasn't due for two more months. To stop the labour, she was pumped with magnesium and was asked to stay at the hospital until the baby was born.

However, she went into labour seven days after she was put on hospital bed rest. The labour was so painful she "could barely speak" and added to it doctors told her that she may not be able to hold her newborn right after birth.

"That's where the unexpected nature of this whole fiasco really hit home," she says in her memoir.

"When you have a healthy pregnancy, you never wonder if you'll get to hold your son right after he's born. It's a given. I was terrified, but I also knew I had to be a soldier."

Faris' struggles did not stop after giving birth to her child as a pediatric neurosurgeon told her and her former partner Pratt that their son might be developmentally disabled with a severe brain bleeding at birth. However, they were told their son's health condition would not be definitely known until he was 18 months old.

"Chris and I did what we could, which was hold hands and hope and face it together. We know how fortunate we are to have a happy ending," she says.

"So the fact that we have a charming and outgoing and athletic kid who loves dinosaurs and introducing himself to people, Chris and I are both grateful every day. We count ourselves extremely lucky."