Mathers seems oblivious to the chaos around her as she carefully studies one of many maps of the local area on the walls. She appears calm and focused, although she has more than just policies and pamphlets on her mind.
She is six months pregnant with her first child, but thoughts of pushchairs and baby clothes are having to be put on hold until after the election.
"My husband and I have discussed some names, but we don't know the sex yet," she says. "I've barely had any time to think about cots and clothes and all the other baby paraphernalia. We'll think about that come 4 May!"
The baby is due in July, during the parliamentary recess, providing 37-year-old Mathers with a convenient window for maternity leave should she be elected. However, she makes it clear that she is keen to return to the workplace as soon as possible.
"Professional women have babies all the time, and they often choose to juggle work and motherhood. There's absolutely no reason that it should be any different for a politician," she says.
"I will choose to return to work, and I really endorse the element of choice for mothers. It's up to the state to support women, whether they want to stay at home or go straight back to work. However, I do think that there should be more support available. Maternity provisions in this country are still terrible compared to most of mainland Europe."
Despite her concerns, Mathers is confident that the childcare facilities at Holyrood are more than adequate.
"The Scottish Parliament was established as a very family-friendly place," she says. "There are plenty of MSPs with children, and they manage to work fairly normal hours. I'm not sure that it's the same at Westminster - at Holyrood, they actually go home in the evenings."
Mathers breezes around the stuffy office in a loose-fitting beige suit, taking calls and leafing through piles of paper. It's a particularly hot day, and the sun streaming through the window is turning the office into a greenhouse.
However, she insists that now is not the time to be putting up her swollen ankles, and that hitting the campaign trail while heavily pregnant has not been a problem.
"I've been very lucky. No morning sickness or tiredness, and I have a very supportive husband, which always helps," she says. "I was never actually worried about my pregnancy affecting the campaign. The people that I've encountered on the campaign trail have all been very supportive, and perhaps it helps them to relate to me more, makes me a little more human."
Far from holding her back on the campaign trail, Mathers has found that her pregnancy has helped her to focus her policies.
"I've found my pregnancy very interesting from a policy perspective," she says. "Issues surrounding health and education have become even more important to me. I'm extremely impressed with the health professionals that I've come across in the NHS and I'm looking forward to giving birth in an NHS hospital. I've been particularly impressed with the level of choice I've been offered. I was given the choice of a home birth, for example."
Mathers is not unsympathetic towards Ruth Kelly, the local government and equality minister, who chose to send one of her children to an independent school, but insists that her child will be state educated. She does admit, though, to some concerns.
"Both my husband and I were educated at state schools and we both want the same for our child," she says. "There are a lot of good state and independent schools in Edinburgh, but we need to invest in education so that my child can go to a state school and still have the best chances in life.
"I'd hate to feel like I wasn't confident in the school I was sending my child to."
Although she plays down suggestions that hitting the campaign trail while six months pregnant might be challenging, she does admit to the odd biscuit craving when I point out a money box in her office that she has labelled "biscuit fund".
"Yes, my sweet tooth has certainly got a little sweeter!" she says, laughing. It seems that aside from the occasional confectionery craving, she is certainly taking pregnancy in her stride.
Well, not quite in her stride. There is just one thing that she admits she is finding very frustrating.
"Having to wear such sensible shoes! I love my heels but I'm forced to wear flats at the moment. I'm still slipping on the heels whenever I can though.
"With my enormous belly, I feel that they balance me out a bit!"