Women who have a baby before they are 25-years-old are more likely than any other age group to have post-natal depression.
A new study by Public Health England spoke to 7,000 women about their reproductive health.
It also found mums aged 16 to 24 were the least likely to share how they’re feeling.
Symptoms include frightening thoughts, feeling sad or finding it difficult to bond with your baby.
Stefani was 21 when she had her first child.
She’s now got three kids and had severe postnatal depression after each birth.
“I think initially I didn’t want to admit I was failing, or at least that’s what it felt like, so when it came to asking for help, at first I was very resistant,” she tells Newsbeat.
“I felt like there was very little that I was doing right and I felt out of my depth.
Stefani describes feeling like everyone was doing better than her and not understanding why she was struggling.
Eventually, she went to her GP and then told her family what was going on.
– Lindsay Brown