Desiree captioned the photo, "Whoa mama! I feel like the baby's grown a foot in the last few weeks! The countdown is officially on and the prep work finally begins."
Click through below to see who else in the Bachelor family is expecting!
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Ashley Hebert and J.P. Rosenbaum
The Bachelorette couple welcomed a baby girl named Essex Reese on Nov. 4. The duo is also parents to son Fordham.
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Season 4 Bachelorette winner Jesse Csincsak revealed exclusively to Life & Style that he and wife Ann Leuders, a Bachelor alum, were expecting their third child. The couple welcomed son Carter James on Dec. 27.
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The former Bachelorette and her fiancé Kevin Manno welcomed a baby girl named Molly Sullivan on July 6.
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The Dancing With the Stars and Bachelor winner welcomed a baby boy named Cayson Jack in May 2016 with hubby Tye Strickland. The couple is already parents to daughter Ava Grace and son Beckett Thomas.
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The former Bachelorette star welcomed her second child with husband Stephan Stagliano in March 2016.
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The Bachelorette alum welcomed a baby boy named Leo in August with fiancé Justin Pasutto.
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Known as the "Onion Girl" on Chris Soules' season of The Bachelor, Ashley welcomed son Brooks on April 7, 2016, with hubby Austin Brannen.
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Sean Lowe and Catherine Giudici
The Bachelor and Marriage Boot Camp couple welcomed a baby boy named Samuel Thomas over Fourth of July weekend in 2016!
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The former Bachelor Pad contestant gave birth to a baby girl named Holland on Sept. 19.
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The former Bachelorette welcomed a baby boy with husband Tyler Johnson on Sept. 17, just 14 months after giving birth to son Jennings. Emily is also mom to a daughter named Ricki from a previous engagement.
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The Bachelorette alum and his wife Emily Tuchscherer welcomed a baby boy named Bowen Michael a month early on Oct. 12.
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Chris and Desiree (Hartsock) Siegfried
The Bachelorette alums welcomed a baby boy named Asher Wrigley on Oct. 19. "He already has us wrapped around his precious little fingers!" the proud mom wrote.
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Renee Oteri Maynard
The former Bachelor contestant, who was eliminated in week eight of Juan Pablo Galavis' season, welcomed her third child, a baby boy named AJ, on August 12.
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Chris and Peyton Lambton
The Bachelorette runner-up and Bachelor alum welcomed their first child, a daughter named Lyla, in November.