I feel like with enough rest her body would be able to handle it, she was going through so much stress when she had Alec. She was also pretty young when she got pregnant (not sure if she's 18 or 19). This is why teenage pregnancy aint good, a female body needs to be fully mature to handle the risks of being pregannt and labor.
On the contrary, she'd have an easier time now compared to her first pregnancy. She's far healthier, body more prime for childbearing since she's now in her 20s, and she's quite active in physical labor judging from the hints we see of her working along with other citizens of her domain.
HRemember, during her first pregnancy, they were in the middle of a battle. Plus the added mental stress, lack of sleep, and whatever else during the time she thought her husband was dead. That piles up and caused complications during birth.
Wouldnt Bianca risk dying again if she had another baby? ;-; Or can she perform the miracle again?