Some Twihards are getting more than they bargained for during screenings of The Twilight Saga: Breaking Dawn - Part 1 the second-to-last film in the Twilight series. The much anticipated birth scene, where Bella Swan delivers her half-vampire baby amidst flashing red, black, and white images, is reportedly triggering seizures in audience members with photosensitive epilepsy.

It's like a light switch going off, because it hits your brain all at once, Dr. Michael G. Chez, the medical director of pediatric neurology and epilepsy for Sutter Medical Center in Sacramento, Calif., told CBS Sacramento.

According to Dr. Chez , many people with photosensitive epilepsy can go through their entire lives without knowing they have the condition, as a seizure will only happen under specific conditions.

Brandon Gephart is one of these people. Gephart accompanied his girlfriend, Kelly Bauman, to an opening weekend showing of Breaking Dawn and ended up in the hospital after the birth scene found him convulsing, snorting, trying to breathe on the floor of the theater.

He scared me big time, Bauman told CBS Sacramento.

A 1997 episode of Pokeman reportedly triggered seizures in hundred of children in Japan, and was subsequently pulled from rotation and never aired overseas. The incident prompted an investigation and a revision of broadcasting guidelines that eliminated the type of flashing light scenes believed to cause convulsions among viewers.

The trouble with theaters, it's dark, the lights flashing in there is more like a strobe light, Dr. Chez told CBS Sacramento.

A Salt Lake City, Utah, man experienced a reaction like Gephart's to the birth scene. The man spoke to ABC4 but did not want to be identified for fear he could lose his job.

I think I blacked out, he told ABC4. According to [my wife] I was shaking and mumbling different noises.

I was kneeling in front of him and slapping his face, his wife added.

The couple told ABC4 they returned to the theater the next day to retrieve the man's cell phone, which they had left behind in the commotion, and were told a female audience member had also experienced convulsions during a Breaking Dawn screening, but the theater manager did not corroborate that report.