Zona claims she’s been pregnant more than three-and-a-half years and that no one believes her. She claims that her breasts are tender, she has extreme mood swings and that her stomach moves – and that even though she had her tubes tied when she was 20, she’s “1,000 percent” certain she’s giving birth to multiples.

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However, Zona says that when she goes to doctors and they perform tests, they always tell her she’s not pregnant.

Zona claims she has what is known as a cryptic pregnancy. “Cryptic pregnancy is a pregnancy that you do not show the HCG levels. Either at or around 20 weeks, it may show up, or through the whole entire pregnancy,” she tells Dr. Phil on Tuesday's episode. “Now with the cryptic pregnancy, your HCG levels are so low that the babies don’t even get bones until they’re 2-to-3 years old in the womb.”

WATCH: Young Woman Says Mom Claims She’s Been Pregnant For Almost Four Years

In the video above, Dr. Phil explains to Zona the medical definition of cryptic pregnancy. How does she respond? And, how does she explain the ultrasound showing she has an empty uterus?

On Tuesday's episode of Dr. Phil, Zona is given an exam by an OB-GYN who has delivered nearly 8,000 babies. Does she believe Zona is pregnant? Check here to see where you can watch.

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What An OB-GYN Says About Woman Who Claims She’s Been Pregnant For Nearly Four Years