Aberdeen North MP Kirsty Blackman has been warned after taking her two young children to work in Westminster.
Ms Blackman was unable to arrange childcare for her two-year-old daughter Rebecca and son Harris, five, so brought them with her to a committee hearing.
The UK Parliament has no creche and the nursery only offers six-week bookings, which Ms Blackman said were unsuitable for her children, who live in Aberdeen.
She said: “My children were down in parliament and, because they don’t live in London, they couldn’t use the nursery.
“The school holidays in Scotland start on July 1 but parliament doesn’t break up until 23rd, so childcare is an issue.
“They were very quiet and well-behaved but Rebecca started to fall asleep so I went and picked her up and held her on my lap. That’s against the rules.”
Ms Blackman added that providing childcare facilities was essential in making sure mums could become MPs.
She said: “I genuinely don’t see how you could possibly be a single parent and a parliamentarian right now.
“We want parliament to be representative and people from all walks of life are able to be parliamentarians.
“We need to make sure there are no barriers to people coming to work.”