"Contractions are actual hell but the epidural is heaven.... so I'm doing great," Witney wrote, according toPeople.
Witney documented her last days of pregnancy this past weekend with a final baby-bump selfie in which she was rocking a gray sports bra and matching sweatpants.
"Passed by this mirror today and couldn't believe how big this boy has gotten," Witney captioned the image at just about 39 weeks pregnant.
"I'm officially DONE & so ready to meet him! Any suggestions on how to start this labor?!"
Although Witney never wanted to have a c-section, she seems overjoyed to have given birth to a healthy boy.
Witney previously said on Instagram she planned to get "induced at 39 weeks."
"I just don't want the risk of having a C-section," Witney said in Fall 2020, People reported.
"I asked my doctor about that and he said the best way is to be induced. He said there's been a lot of studies about how they've had less C-sections with women who were induced versus women who waited until full-term -- so that's kind of what I'm basing my decision off of."
"Baby McAllister coming Jan 2021!!!!! We can't even contain our excitement and joy right now," Witney wrote alongside a photo of herself embracing her husband while holding sonogram photos and a positive digital pregnancy test.
Witney said finding out she was pregnant felt "surreal and special!"
"We love this little bean so much already and we can't wait to start this beautiful chapter in our lives! #15weekspregnant #mcallisterbaby #clearbluepartner #clearblueconfirmed," she added.
Witney then announced in August 2020 she had a baby boy on the way. She and Carson discovered the baby's sex at a big gender reveal party.
Witney, who married her high-school sweetheart in Salt Lake City on New Year's Day in 2016 after dating for four years, told Us Weekly in October 2019 that she had baby fever and wanted to have a child with Carson "so bad" soon.
"We're not really putting a timestamp on it, just when we feel ready," Witney told Us at the time.
"I get so baby hungry though. Like, every time I see a baby it breaks my heart. I want one."
Witney previously worried, however, about one "big issue" in regards to getting pregnant.
"Can you start a family and still have a career and still dance?" Witney questioned, according to the magazine. "Peta has been a really good mentor to us through what we would do when we eventually have kids. She's been awesome."
Witney had also revealed she "wants a lot of kids" but "four is going to be the [maximum]" for her family.
Days before Lindsay welcomed her first child, she told Entertainment Tonight that she was looking forward to being a first-time mom with her BFF Witney by her side.
"It's actually insane," Lindsay said at the time.
"We've done so many things in our lives together, so it's like, naturally, why wouldn't we get pregnant together? It's so funny because you can't really plan a pregnancy. I mean, you can plan when you want to try, but it's not like it's always going to happen when you want it to."
Lindsay added, "It's perfect we have a boy and a girl. I feel like it'll be good because boy and girl friend relationships are so much fun. They can be partners, maybe girlfriend, boyfriend, who knows."