Hilaria Baldwin is battling pneumonia - and two of her kids have the flu.

The 34-year-old fitness and wellness expert welcomed her fourth child, a son named Romeo, into the world last week, but has admitted that her first week as a mother of four has been ''adventurous'', after most of her family - including her other children Carmen, four, Rafael, two, and Leonardo, 20-months, all of whom she has with her husband Alec Baldwin - have fallen ill.

Alongside a picture of Romeo, Hilaria wrote in a lengthy Instagram post on Thursday (24.05.18): ''It's been quite an adventurous week with highs and lows...Romeo was born last Thursday and is a complete joy...however, I was also diagnosed with pneumonia, Rafa and Leo with the flu, Carmen came home from school with pink eye. Tumultuous to say the least, and, for a family that rarely gets sick, definitely a foreign experience. (sic)''

Hilaria added that luckily, little Romeo is ''super healthy'', but she has still been left ''stressed out'' as she and her 60-year-old spouse Alec have been attempting to ''quarantine'' their growing family.

She continued: ''We are all on the mend, and fortunately, so far, Romeo is super healthy. It's been tough getting our new family of 6 oriented with all of the necessary quarantining. The recovery from birth, the beginnings of breastfeeding again, the sleepless nights, taking care of sick toddlers, dr visits, my own health...I just keep on saying ''we got this''.... I have definitely had my stressed out moments and have had to practice lots of breathing and perspective, trying to stay as calm and positive as possible. I'm looking forward to renewed health for my family, and one day, to look back and have a little laugh. #WeGotThis2018 (sic)''

Hilaria and the 'Boss Baby' actor - who also has 22-year-old daughter Ireland from a previous relationship - welcomed Romeo into the world last Thursday (17.05.18), and revealed his adorable moniker earlier this week.

In a separate Instagram post, Hilaria wrote: ''We are happy to introduce you to Romeo Alejandro David Baldwin.''