Jenelle and her boyfriend of one-year, David Eason, announced their news on social media and revealed to fans that their first child together is a girl.
The pair both have two children from previous relationships. They have planned to call their daughter Ensley Jolie Eason.
Taking to Instagram, Jenelle has shared a series of photographs taken on Halloween. In one shot, she is cradling her baby bump while David is mimicking her pose with a pumpkin. Captioning the picture, she told fans she is "truly blessed" to have him in her life.
Jenelle wrote: "Every family needs a good father to anchor it. This man has always put our #FamilyFirst since day one. I'm truly blessed and one very lucky woman to call him mine. @easondavid88 #WhosPumpkinIsBigger?"
Another shot, taken by David, shows Jenelle sat on a stack of pumpkins among a patch. Addressing her unborn child, she said: "Miss. Ensley, we are waiting patiently for your arrival and wish it wasn't taking so long!
"Everyone is super excited to meet you and cannot wait to hold you. Such a joy to bring a little girl into our big family. Love you baby girl!"
Jenelle first appeared on MTV's Teen Mom following the birth of her son Jace. However, her life soon spiralled out of control and, with her ex-boyfriend Andrew Lewis out of the picture, Jenelle's mother Barbara gained custody of Jace in 2009.
Having cleaned up her act, Jenelle is currently seeking to regain custody of the now seven-year-old. She is also mum to son Kaiser, two, who she had with her ex-fiancé Nathan Griffin. Nathan was jailed during Jenelle's pregnancy for driving on a suspended license.
Despite her troubled past, Jenelle has been working hard to turn her life around. She began dating David, who has a son and a daughter from a previous relationship, in 2015.
The couple's baby is due in January.
Meanwhile, Teen Mom UK will premiere on Wednesday night (3 November) - and here is everything you need to know!
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