A woman whose stomach swelled from 32 inches to 49 inches may have looked pregnant to the rest of the world, but it turned out the massive bulge was actually a 17-pound ovarian cyst, the Daily Mail reported.

Janet Delaney, who already has two grown children, knew she wasn’t pregnant because she had her tubes tied 13 years ago. Still, doctors didn’t know was what wrong with her.

At first, Delaney, who lives in Manchester, England, was diagnosed with irritable bowel syndrome (IBS) and given medication. However, the medication did not work.

It was then that Delaney insisted the hospital perform an ultrasound and that’s when they found the massive cyst.

“I looked nine months pregnant — strangers were giving up their seat for me on the bus, asking me when my baby was due,” Delaney told the newspaper.

Dr. Manny Alvarez, chairman of the Department of Obstetrics and Gynecology and Reproductive Science at Hackensack University Medical Center in New Jersey, told FoxNews.com that this was most likely a dermoid cyst, which is one of the most common ovarian cysts.

“Usually these cysts are benign,” Alvarez, who is also the managing health editor of FoxNews.com, said. “They tend to evolve with time since most of them originated when the ovary is being formed. They are embryonic types of cysts and usually contain elements of different types of tissues, skin, hair and teeth and they can get quite large.”

Delaney eventually underwent a 5-hour operation to remove the cyst, which was so big that it took two doctors to remove it, according to the report.

“Ovarian tumors are usually asymptomatic until they get to a certain size, which can create symptoms such as abdominal distention and back pain,” Alvarez added.“That’s when many women seek medical help. But by that time, the tumor has grown to a significant size.”

Click here to read more and see photos from the Daily Mail.