Seven years ago, a group of nine pregnant women met in an antenatal class at Adelaide's North Eastern Community Hospital.

Now, with a combined 22 children between them, the mothers group — who call themselves the "Maybe Babies", as they were all due to give birth in May 2013 — is still close.

The group meets at least once per fortnight and continues to celebrate milestones in their own personal lives as well as their children's lives.

There are many benefits in joining a mothers group, including peer and social support, and most importantly, social interaction that experts say is protective against postnatal depression.

North Eastern Community Hospital's gynaecologist and obstetrician Valerie Thompson said it was important for new mothers to be a part of a group as it provided social support.

"In the early months and days, it is a very big adjustment," Dr Thompson said.

"Social support is really important because it can protect against postnatal depression and PND is really common."

Three-month-old Oscar Cameron is the youngest child in the group.

"I mean we went from the newborn stage to the terrible-twos, we sent all of our kids off to school last year, so going through all of those experiences together is just fantastic," said his mother Louise Cameron.

"It's very daunting when you leave the hospital and you come home with a newborn baby, and you know you're not going to know everything, but when you're in a mums group with eight or nine other girls sharing resources and information it's just really nice."

Robyn Curtis said they "all clicked".

"Seven years later here we are," she said.

The children have also formed special bonds.

"We have lots of friends to play with," said Eli Curtis, 7.