The 35-year-old, who has made 27 appearances for the Reds since signing from Liverpool last summer, will remain a part of the squad in what is our first season in the Barclays FA Women’s Super League.
She will take part in a reduced training programme and explore off the pitch activities with the club.
Manchester United would like to congratulate Siobhan and husband Leigh on their news.
“We are both filled with so much love and excitement looking ahead to the coming months, as we prepare to become parents,” said Siobhan, who has won 50 caps for England.