Charlotte and musician Jonathan married in 2017 three months after she announced the couple had suffered a miscarriage.
Charlotte told fans on Twitter on Sunday that she is not taking any chances with her health, after pulling out of charity concert to raise money for flood victims in Wales.
Charlotte tweeted: 'Gutted to have missed it. I'm preggers so I'm airing [sic] on the side of caution in terms of virus. It looks like it was a great success. X'.
In 2017, Charlotte announced to fans that she had sadly suffered a miscarriage.
'Charlotte and Jonny are very sad to announce that they lost their baby. Now is a time for grieving and being together as a family. We kindly ask everyone to respect that peace,’ a statement on her Twitter account read at the time.