"BABY DADDY times two," Astrid, 32, captioned a black and white photo of her husband holding a birthday cake via Instagram Stories.
"Test results came back POSITIVE so we're celebrating @Kevin.c.wendt birthday a day early."
Astrid and Kevin, who welcomed their 14-month-old son August "Auggie" Wendt in November 2021 after dealing with fertility issues and undergoing her first IVF journey, also thanked fans for their "sweet messages" and checking in on the couple.
"It means the world," Astrid concluded.
Astrid revealed she had a successful embryo "transfer day" late last month.
Kevin admitted he has "a lot of empathy now" for couples struggling to conceive a baby.
"The amount of stuff [Astrid] put herself through just to have [our son] is unbelievable," Kevin boasted of his wife. "I think when you have a baby in the end, it's all worth it."
Astrid and Kevin tied the knot on October 28, 2022 at the Powel Crosley Estate in Sarasota, FL, after a three-year engagement and two postponed weddings due to COVID-19 and Astrid's due date with their first child.
The couple -- whose wedding had initially been scheduled for November 2020 before it was pushed back to November 2021 -- revealed how the third time was the charm and their wedding day was "magical" and "worked out" because their son got to participate and take photos.
Astrid and Kevin, who got engaged in August 2019, said that when they decided they were ready to start a family, they tried to conceive naturally for a year.
When that didn't work, Astrid underwent multiple intrauterine inseminations and then started IVF a week before Christmas in December 2020.
Astrid ended up going through two rounds of IVF before getting pregnant for the first time with her son.
Astrid and Kevin were a solid couple on Bachelor in Paradise in Summer 2018, but Kevin blindsided and dumped Astrid before the Fantasy Suite dates and ended up trying to win her back during the live reunion show.
Kevin explained on the reunion special of Paradise's fifth season he had a lot of fears and insecurities he had to deal with via therapy regarding his previous romances before being able to commit to a woman wholeheartedly and settle down.
One of Kevin's exes is Ashley Iaconetti, whom he met on The Bachelor Winter Games but split from in March 2018.
"I will never forget when I left the show, going to my best friends and being like, 'I know we technically broke up on the show, but I'm pretty sure this is the person I'm going to marry,'" Astrid previously told People.
"I feel like I knew right away how well he fit into my life."
Back in November 2018, Astrid and Kevin's families reportedly met each other at an event in Toronto, Canada, and then the following month, Astrid -- who worked as a plastic surgery office manager in Tampa, FL -- moved in with Kevin in his hometown of Toronto.
Prior to appearing on Paradise several years ago, Astrid competed to win Nick Viall's heart on The Bachelor's 21st season, and Kevin found fame when he won the debut season of The Bachelorette Canada in 2016 and then appeared on The Bachelor Winter Games in 2018.