"IT'S A......BOY!!!!!!!" Jenna captioned her post along with a blue heart emoji.
"Today we are officially half way there to meeting our son. Saying those words still makes me emotional!! SO EXCITED to be a boy mom. [Crying emoticon]."
Val, 36, posted the same photos on his own Instagram account and captioned them with a blue heart. Jenna previously said Val is "going to be the best dad in the world" and has been so "selfless and loving" during her pregnancy.
"Our biggest dream come true yet," Jenna wrote on Instagram on July 15. "Baby Chmerkovskiy coming this January! My heart has grown beyond comprehension while growing this little miracle inside of me. We can't wait to meet our precious angel."
Jenna also posted a video showing the moment she had discovered -- after taking an at-home pregnancy test -- that she's expecting.
"The moment my whole world changed. We had actually stopped trying to conceive for about 6 months to mentally/emotionally give ourselves a break... so the shock, disbelief, and sheer joy in this moment is a memory I will never forget," Jenna captioned the video, which showed her celebrating and crying tears of joy.
"I want to keep this moment very positive because there is so much to celebrate and my heart is overflowing with gratitude, BUT our journey getting to this point wasn't an easy one," Jenna revealed.
"I remember watching people share these videos and aching because I wished so badly I could experience that joy. After two years of infertility, and hundreds of negative tests after negative tests, it was heart wrenching at times to stay optimistic and made me question whether I would ever have this opportunity."
"I can't stop staring at it. I would show you but it will give the gender away hehe. Baby is SO lucky to have the best aunties already!!!"
Jenna's disclosure that she had a two-year battle with infertility followed a June interview in which she had been critical of fans asking her when she's going to have a baby or why she wasn't expanding her family.
"I think it's a really insensitive question, actually, because... you never know what somebody is going through," the dancer and choreographer told Us Weekly a few weeks before announcing her pregnancy.
"And the amount of DMs and comments -- you know, 'babies on the brain' and 'when are you going to have a baby?' -- it adds pressure but also it's nobody's business," she complained.
Jenna said although she is in the public eye, people have "no idea what [she's] gone through."
"[People don't know] what we want in the future," Jenna explained, speaking on behalf of Val as well.
Peta, who has served as a professional partner on Dancing with the Stars on and off since 2011, recently broke the news to People that she had three miscarriages in two years while trying to give her five-year-old son Shai a sibling.
Jenna and Val began dating in 2015 and the Ukrainian native proposed marriage in Venice, Italy, in 2018.
Val and Jenna tied the knot on April 13, 2019 in a romantic ceremony overlooking the ocean at the Terranea Resort in Rancho Palo Verdes, CA.
"Mr. & Mrs. Chmerkovskiy 04~13~2019," Jenna captioned a wedding photo that she shared on Instagram.
Prior to joining Dancing with the Stars as a Troupe member and then being promoted to a pro partner for Season 23, Jenna competed as a contestant and All-Star partner on separate seasons of So You Think You Can Dance.