The mum-to-be also shared with her followers that she was planning a caesarean birth, admitting she felt "incredibly overwhelmed and nervous."
"The birth of my last babe is looking very different to the birth that I have envisioned and fantasised about for the last 34 weeks," she wrote on Instagram.
"I have one last ultrasound next week to see if my placenta has done what it needs to do to give me the final birth that I so badly want. I have however already grieved for that experience and am now sitting in and accepting my new reality, that I will most likely be a belly-birthing Mumma."
"It’ll be different, but it will be just as beautiful as the births of my two boys."
Late last year Alex opened up about her emotional third pregnancy and why she knows it will be her last in 9Honey’s ‘Pregnancy Diaries.’
"Sadly, this is going to be my last pregnancy. I haven't enjoyed it,” she shared.
The star revealed the difficult physical symptoms and side effects she had been dealing with this pregnancy, including nausea, heart palpitations, fainting episodes and anxiety.
Despite loving her first two pregnancy experiences, Alex revealed that her current pregnancy was nowhere near as easy - and not only has it impacted her own mental health but affected her relationships with her partner and sons.
Alex already has two children, a son Maxwell, who was born in August 2021, whom she shares with partner Carson Jory and Elijah, 11, from a previous relationship.