My cats' relationship detiorated after my cat gave birth.

My cats, Lucy and Winnie always had a great relationship, they came together when I bought them a year ago, Winnie is fixed and Lucy isn't. Two days after Lucy gave birth, Winnie wasn't acting all that aggresive towards her but Lucy wasn't the same, she tried lunging at Winnie, so I put Winnie in a seperare room.

I took a minion hoodie and tried swapping scents, and the two had gradually started sitting on the article of clothing after a few days so I opened the door open a crack and they acted normal, Winnie even tried to pry the door open a tiny bit with her paws, but I stopped her.

It's been around a week now and I sometimes take Winnie out to see Lucy, she's hissing and growling in my arms, trying to attack Lucy instead of the other way around.

I've also tried brushing them both with a comb and letting them smell eachother and they act fine, not hissing at the hair on the comb or anything.

I'm in a serious pinch because I don't know what to do.