A/N ok this is my first Twilight fan fic, so go easy.
This fan fic was grossly inspired by a rather revolting question that one of Stepehenie Meyer's fans asked her; "What happens when Bella gets her period?". In the article I read, I never got the answer so I decided that she doesn't. This is kind of sad but interesting. Hope you enjoy it.
Reviews please. Also title suggestions would be awesome. 'cause this one is pretty much crap.

In Detail

Bella's P.O.V.

I left Edward down stairs with Jasper and Emmett, telling him I was going to look for Alice. In truth, I was actually looking for Rosalie. It shouldn't be long now until I'm changed; if Edward won't do it I'll just ask Alice or Carlisle, its way too dangerous for me to be human.
I knocked on the door of Rosalie and Emmett's room and heard Rosalie's startled voice come from inside "Come in Bella."

I opened the door to see her sitting at an old fashioned vanity table brushing her long hair. Rosalie and Emmett's room, like Edwards, had a couch and a wall of windows. The couch was the only comfortable item of furniture apart from the chair Rosalie was sitting on.

"Can I help you with anything?" Rosalie asked.

"Uh, I want to tell you something." I took a deep breath before I continued. "So I know you don't why I'm so willing to give up being human to become a vampire. Why I don't mind missing out on all the humane experiences you and Esme have missed out on. Like having a family and everything, living a normal life and stuff, I know you always wanted to have a child of your own and could never understand why I was so willing to give that up. And now I want you to understand why," I said.

Rosalie looked at me questioningly and I took that as an invitation to continue. "The reason why I'm so eager to give that up, especially the change to have a baby-" My voice broke and I took a deep breath before I continued. "Is because I can't have a baby. I'm infertile. "

Rosalie stared at me disbelievingly. "What?" she asked shocked.

"I'm infertile," I replied. "I can't have children."

"How? Why?" Rosalie asked, her face shocked and bewildered.

"I don't exactly know why," I said thoughtfully. "And how? Well uh, I'm not sure if you remember anything about women's menstrual cycle?" I questioned my eyebrows raised. This was kind of weird and embarrassing, no one but me and my mom knew about my infertility. It's not something that simply rolls off the tongue.

Rosalie frowned thoughtfully searching through her faded human memories, after a moment she shook her head and looked back at me expectantly.

I sighed and tried to figure out how to explain this to a nearly 100 year old vampire. "Ok so for 'normal' girls, once a month they get their period which lasts roughly 3 or 4 days. It gets rid of all the stuff in our bodies that, during pregnancy, is used to help the baby grow in our womb. I don't get my period. Some girls just don't, most girls do though but I'm part of the minority and that's why I'm so willing to give up my humanity."

Rosalie just stared at me in shock for a moment. "Are you sure?" she asked, her voice barely audible, I had to move closer to hear her.

I nodded slowly. "I'm 18. It should've happened by now, long ago." It no longer affected me, being infertile. It's always been a possibility since I'd been 15.

"Oh Bella," she said softly. "I'm so sorry." She reached out and pulled me into her hard marble arms. "It must be horrible for you!" she exclaimed when she pulled away from me, her eyes containing a sadness that made me sad just to look at.

I simply shrugged looking up at the dark ceiling. "Not really," I said. "I'm sort of used to it now. I don't know anyone that's pregnant or that has young children or anything. Besides, I have Edward, he's all I really need in my life." She reached towards me again and hugged me tight, resting her head against my shoulder so all I could see was her long blonde hair flowing down her back. "Now you know that in that respect, I'm the same as you," I murmured softly.

"I'm sorry Bella, about what I said, about this, about everything. I could never imagine what this must be like for you. At least I had the chance," she said sadly.

"Yeah," I mumbled as she released me and we sat down on the couch.

"Please forgive me."

"Sure," I said smiling at her timidly. "I need to ask you a favour though…"

Rosalie reached out to grab my hand. "Anything," she said earnestly.

"Don't tell Edward," I requested quietly.

She looked at me dismally. "That's no easy feat Bella, keeping things from Edward. Not all of us are immune to him like you."

"Just for a little while," I said pleadingly. "Just until I'm changed. I don't want him to try to convince me to try or to use it as an excuse not to change me."

"Bella," Rosalie began slowly. "Why don't y-"

"No Rosalie," I said firmly. "Even if I could have a baby I wouldn't be able to have it with who I want to. I am in love with Edward and having a baby won't change that."

She opened her mouth to protest but I held up my hand, letting go of hers, to stop her. "Rose please," I said, using her family's nickname for her. "Just try not to tell him."

Rosalie sighed heavily and her blonde hair floated gracefully around her as her shoulder's slumped. "I'll try," she said dejectedly.

"That's all I can ask for," I said smiling at her. "Just try thinking about something else," I suggested remembering how Alice had hidden my realisation from Edward during our graduation ceremony.

Rosalie's lit up gleefully. "I've got an idea," she said, jumping up gracefully and pulling me up awkwardly beside her. She led me out of her room and down the hall to the stairs.

"I actually feel a bit sorry for Edward right now," Rosalie mused thoughtfully, her eyes still gleeful. I looked at her warily as she towed me down the stairs with a wicked grin on her perfect face.

"What the hell Rose?" Jasper muttered, raising his eyes to the ceiling. He took his eyes off the video game for only a moment but a moment was all it took for Emmett to decapitate his character.

"Score!" Emmett yelled triumphantly throwing the controller he had been playing with in the air where it there hit the roof with a loud bang before crashing to the floor in pieces.

"Emmett that's the third controller this month," Edward complained from his seat on the couch. "We may as well buy the company the way you're going!" Edwards eye's flickered to Jasper in response to his thoughts. "What is it?" he asked Jasper.

"Rose," Jasper replied slowly. "She's...she's feeling something." His brows furrowed in confusion. "That's weird she's feeling...pity."

"So?" Edward said. "It's Rosalie. She always pities herself. It's all she ever thinks about," he said rolling his eyes.

Emmett growled at him and Edward grinned at him good naturedly turning back to Jasper.

"No it's not self pity," Jasper continued, still slow and thoughtful. "She's pitying someone else. She's pitying Bella," Jasper said surprised, looking at Edward in confusion.

"Bella?" Edward asked sitting up straight. "Why is she pitying Bella?"

"What are you asking me for? You're the mind reader," Jasper snapped.

"She's probably feeling sorry for her because she's going to spend eternity with you," Emmett said sarcastically.

Edward ignored him and focused his eyes and mind upstairs.

"Well?" Jasper asked after a few minutes.

"She's feeling sorry for me," Edward said, confusion lining his voice. "I wonder why-oh my God!" He cut himself off mid-sentence and scrabbled at his eyes as if to block out whatever Rosalie was thinking. "Oh God! Rose stop," he exclaimed pleadingly, writhing on the couch.

Rosalie just giggled and flitted over to sit behind Emmett on the couch. Edward continued to scrabble at his face as if he was trying to claw his eyes out. "Rose, please," he moaned.

"Fine," Rosalie muttered and Edward relaxed looking over at me for the first time, he grimaced at me. "You didn't have to look you know," Rosalie added under her breath.

I sat down on the cough between Edward and Rosalie. "What did you think about?" I asked Rosalie leaning towards her.

She looked over at me and leaned even closer a smile on her face. "I thought about what Emmett looked like naked. In detail."

I heard Edward groan beside me as I struggled not to laugh.