What do these two women have in common? They're both pregnant — and, believe it or not, they're only four weeks apart. View this photo on Instagram Instagram: @chontelduncan The woman on the left is Chontel Duncan, a fitness model and former Miss Universe contestant from Australia. In this November photo, which this week went viral, she was 21 weeks pregnant. She is due to give birth at the end of March. On the right is her friend Natalie Smith, who was due at the beginning of March with her third child."Each woman carries differently and this most certainly doesn't mean one is doing something wrong or not healthy," Duncan wrote on Instagram. "We both have healthy growing babies and we both have had incredible pregnancies so far." Duncan uses her Instagram account to show that healthy pregnancies can come in many different shapes and sizes. View this photo on Instagram Instagram: @chontelduncan While most commenters have been positive, a fair share have criticized Duncan for exercising while pregnant — though doctors say doing so is almost always totally safe."Once it became clear to me (through my social media posts) how foreign it was to see a pregnancy performed like mine, it did get me thinking, 'Maybe I should continue to document my pregnancy because it seems that we are misled to believe that we are more fragile than we really are,'" Duncan told Today Parents. "We lose focus on one of the most important components (of a healthy pregnancy,) keeping ourselves physically and mentally strong." This is Duncan's most recent update, looking like a total beast at 37 weeks, and with just 21 days to her due date. View this photo on Instagram Instagram: @chontelduncan Duncan said that in spite of her thin, muscular figure, she "couldn't care less" how her physical appearance is affected by pregnancy."I respect my body, I'm disciplined, I look after my health, and it was most certainly not to be a silly size zero," she said.