They went in for her 12-week scan and afterwards, the technician doing the scan said she had "something to tell them".

"I thought, 'Is everything okay?'," Emma, 30, said.

"The lady said, 'There's more than one heartbeat'. And we said, 'Twins?'.

"And she was like, 'Oh, no there's three'.

"I think I pretty much started laughing and didn't stop for 10 minutes.

"The adrenalin just went through my body and I couldn't sleep all night. The next day, I just crashed."

The three identical girls are due to be delivered in two to four weeks at the Canberra Hospital.

That will mean Emma, and Matt will have six children under the age of 12.

They now have Patrick, 11; Laura, seven, and Lily, five.

The couple did want another child - "but not quite yet". The triplets were a complete surprise, conceived naturally without any fertility drugs.

The fact all three girls are identical makes them particularly special.

Various sources say the chances of having identical triplets range from one in 60,000 to one in 200 million pregnancies.

"I think Matt and I were both gobsmacked," Emma said.

"It was something we were not expecting."

Canberra has celebrated identical triplets before.

Former ACT resident Tom Hepner (formerly Kaminskas) and his American wife Hannah, welcomed identical girl triplets at a hospital in California in 2013.

Bombala couple Karen and Scott Guthrie had their hands full with their identical triplet boys born at the Canberra Hospital in 2012.

The first triplets in Canberra were the famous French boys, Tom, Mick and Bob, from Narrabundah, born in 1958 and also identical.

ACT Health says seven sets of triplets have been born in the Territory to Canberra residents between 2011 and 2015. Data from other years was not available and ACT Health does not count whether the triplets were identical or not.

The Keen babies, meanwhile, will be delivered six to eight weeks' premature and will be cared for initially at the Neonatal Intensive Care Unit at the Canberra Hospital.

Matt, 34, a self-employed plumber, has recently built on a four-bedroom extension to their home in Chisholm to accommodate all the children.

The build has kept him away from his day job and stretched the family finances considerably. They still need to paint the extension and add on doors but money is tight.

Then there is the question of how to transport all six children. The family has a 2006 VE Commodore and no means at this stage to upgrade to a bigger vehicle. Warm winter clothes for the triplets are also on the family wish list.

Emma, an administration officer, has been on sick leave since she was 17-weeks' pregnant due to severe morning sickness.

Despite the big change about to hit their lives, Emma is still giving her time to the community.

She has made herself available to help promote the Australian Breastfeeding Association's new class in the ACT to help mums who are breastfeeding multiples. The association's Jessica Armstrong said the classes were about passing on information to mums of more than one infant and letting them know support was available.

Emma is determined to breast feed the triplets after also breastfeeding her other children.

"My littlest was very excited," Emma said, of the coming siblings.

"When I told my son, he said, 'How are you going to feed them when you only have two boobs?'," Emma said, with a laugh.

The answer is with lots of support from the breastfeeding association - and lots of expressing.

"I just think if they're going to be premature babies I want to help give them that boost right from the start of their life," Emma said.

"I want to give them a go. I think it's better to give it a go and possibly fail than not try it at all."

If you can help the Keen family in anyway please send an email to megan.doherty@fairfaxmedia.com.au. The first ABA breastfeeding class for multiples is at the Pearce Community Centre on April 7. For more details ring the Australian Breastfeeding Association ACT/Southern NSW region office on 6162 2716.