"I feel like I've been pregnant for six years!" the Keeping Up with the Kardashians star told PEOPLE at the Operation Shower baby bash for military moms in Jersey City, New Jersey, on Monday.
Jokes aside, Khloé says all the premature baby buzz took some getting used to.
"I used to get offended, like, 'Do I look fat today?' or 'Why are they saying that?' But they just say it," says the reality star, who recently celebrated her 30th birthday with rapper boyfriend French Montana.
"Before I was like, 'Do I have a baby bump? Is my belly sticking out?' But no," she adds. "I mean, one day the rumor will be true, I hope, but who knows? Until then, it is what it is."
Khloé, along with sisters Kim and Kourtney, teamed up with Babies "R" Us to host the Operation Shower event. The nonprofit, founded in 2007, throws baby showers for military moms-to-be, and has so far provided essentials to more than 200,000 women and families.
The women's care packages on Monday included items from the sisters' Kardashian Kids collection.
"These women, their husbands are deployed, and it's a stressful time. But they're also having such a joyous time having a baby," Khloé says. "We want to relieve some of the burden by having the shower."
Kim adds that their collection was a perfect fit for the cause. "When we get our line in, we gift it to all our friends. We thought, 'How can we do this on a bigger scale?' " Kim, 33, tells PEOPLE, adding that motherhood has changed her perspective on getting involved.
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Kourtney, 35, couldn't agree more. "Once you're a mom and understand what you're going through, you just have this connection with other moms," she says. "We're excited to be able to be a part of that."
For more from the Kardashians on motherhood and more, pick up the July 21 issue of PEOPLE, on stands Friday.