Octomom Nadya Suleman has a competitive uterus ... because she doesn't want any would-be baby machines taking a shot at her birthing title ... and she's sick of them trying.

Octo had some competition recently from Mexico's NueveMom -- who claimed to be pregnant with 9 babies. Her story might not be true, but if it is ... it could have shot Octo's record for most children delivered at a single birth to survive straight out the window.

Octo tells TMZ she's tired of all the Octofakes lately, telling us, "No one will ever take my Octo title, I’m in the Guinness Book Of World Records!"

She goes on to call NueveMom "a fraud" and says she "shouldn't be making a joke about raising a large family. It’s a serious job and takes a lot to take care of my children. She disgusts me."

Pot ... meet kettle.

NueveMom is no mas ... this according to Univision ... which has information that could prove the woman who was allegedly pregnant with 9 babies ... isn't really pregnant at all.

Univision published a report ... claiming a reporter spoke with a Mexican doctor who performed an ultrasound on Karla Vanessa Perez ... and determined her uterus was "empty."

The doctor told a reporter ... she was unaware of any other ultrasounds that may have been performed ... and says the local Health Dept. is trying to find out who told Karla she was pregnant in the first place.

So, for now ... hasta la vista, baby ... baby ... baby ... baby ... baby ... baby ... baby ... baby ... baby.

Adios OctoMom ... 'cause there's a lady in Mexico who's reportedly pregnant with NINE KIDS!!!!

According to reports, NueveMom has been identified as Karla Vanessa Perez ... who's one month away from giving birth to 6 girls and 3 boys.

Just like Nadya Suleman, NueveMom reportedly had fertility treatments leading up to the multiple pregnancy.

NueveMom told Mexico's Notimex news agency, "It's very early to think of names for the babies ... first I hope that everything goes well."

So far, it's unclear if Perez is married ... rich ... sane, etc.


11:35 AM PT -- FOOTAGE has just surfaced of the NueveMom on a local Mexican news station -- you gotta check it out!!!