A Danish mum has gone viral after video of her belly while expecting triplets was posted to TikTok.

Michella Meier-Morsi gave birth to Charles, Theodore and Gabriel this month after documenting her pregnancy on Instagram.

She shared regular bump updates with her 259,000 Instagram followers, however, a video posted to TikTok by another person gave her bump international attention.

"One more reason for people to respect all mothers," the video, which showed Meier-Morsi hoisting and holding her pregnant belly, was captioned.

The video has since been viewed more than 14 million times, with people in awe at the size – and shape – of her pregnant abdomen.

"It's wild how some babies grow straight out like that as opposed to up and down," one person commented.

"I have no words … but RESPECT!" another wrote.

"I'm speechless! You my dear are a SUPER HERO!" one commenter also wrote.

In the days before giving birth, Meier-Morsi wrote on Instagram she was in "extreme pain" and it felt "overwhelming" to know she would soon welcome triplets.

She announced her sons' births on January 16, describing the process as the "wildest 36 hours".

"The birth went much better than feared – I got it bad along the way, but it was not nearly as bad as last time," Meier-Morsi wrote.

She also shared a photo of her postpartum belly 10 days after giving birth, saying it had "already become significantly smaller" but was "heavy and incredibly painful".

"The last few days, the stomach has felt like a big black mark, it even hurts to breathe," Meier-Morsi said, adding that it would "be exciting and nerve-racking to see how my body plans to heal".

Pregnancy will look different on every woman, with factors like whether it is her first pregnancy, body composition or multiple babies affecting the size of a pregnant belly.

Diastasis recti, a condition where the left and right abdominal muscles separate, can also affect the shape of a pregnant belly.

The condition will mean there's more room in the abdomen and therefore the uterus to stick out more, obstetrics and gynaecology Associate Professor Jessica Kiley at Northwestern Feinberg School of Medicine told Health.com.

"Pregnant women always feel like they look bigger or smaller than their friend, sister or neighbour," she said.

"It's our job as doctors to explain that what's normal for them might not appear normal for other women."