McConnell is Scotland's most medalled track and field athlete and has represented her country or Great Britain at every major championships since 2001.
However the 34-year-old, who reached the semi-finals of the 400m at London 2012, will miss this summer's World Championships in Moscow after revealing she is pregnant.
The baby is due in November and McConnell is hoping to return for the 2014 Commonwealth Games in Glasgow.
"The pregnancy has come as a bit of a surprise but we are absolutely delighted with the news," she said.
"I plan to continue to train throughout the pregnancy but will not be competing this year.
"With regards to the Glasgow Commonwealth Games I would ideally love to be back on the track but it is going to be a big challenge and will depend on how the pregnancy and birth goes but either way I will certainly be keen to be involved.
"2014 is shaping up to be a really exciting year for me. And it's all happening in Glasgow! A home Commonwealth Games, my first baby - I'm really excited."
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