Carrie Symonds gave birth to her first baby, Wilfred two weeks ago.
In a post on Twitter, the new mum praised the team at University College Hospital.
Kit & Kin was co-founded by former Spice Girl Emma Bunton and specialises in sustainable products for babies and children.
The prime minister was out of hospital for less than three weeks before Carrie Symonds gave birth.
There is a very special meaning behind the little boy's middle name.
Boris Johnson and Carrie Symonds - who own Jack Russell cross Dilyn - have announced the arrival of a little boy.
From a £69 M&S coat to statement Anthropologie dress, Symonds' stylish maternity wardrobe was filled with high street heroes.
David Cameron and Tony Blair also had babies while serving as the Prime Minister.
The prime minister and his partner have welcomed a son.
The prime minister's pregnant fiancée also praised the "magnificent" NHS in a Twitter post.
England's chief medical adviser Professor Chris Whitty warned: 'Infections and pregnancy are not a good combination in general.'
The mum-to-be attended the Six Nations game with fiancé Boris Johnson.
She attended a reception at Downing Street for International Women’s Day.
The outfit she wore to meet the Queen set her back £225 - rather than £2,100.
The dress has been slashed to £95.
Carrie Symonds has risen through the ranks as one of politics’ most influential dressers.Since arriving at No.10 with her boyfriend Prime Minister Boris Johnson in July, she demands our attention through her stylish sartorial choices.And while we’d the 31-year-old to own a wardrobe full of luxury items, she continues to champion affordable high-street buys.As a keen conservationist, she also has an eye for eco-friendly and sustainable pieces such as her £255 eco-dress designed by Justine Tabak for her first public speech as the UK’s ‘First Girlfriend’.Whether she’s heading to Balmoral to visit the Queen in something vintage or supporting her boyfriend at a conference in this season’s high-street steal, Carrie’s style is fool-proof. Here’s a look at the First Lady’s work wardrobe and all her most talked about outfits to date.
The UK's 'First Girlfriend' opted for yet another affordable midi dress.
The 31-year-old has a penchant for transitional floral dresses.
It's believed to be the first time Boris Johnson's girlfriend has met the Queen.
Carrie just wore another dress by her favourite British brand