The first hint she had was five weeks after she'd returned from her honeymoon. The guard was bringing her breakfast when, suddenly, the smell of porridge hit her like a brick. Luckily, her wastebasket sat nearby. And she didn't have to clean it up afterwards herself.
By the time the Doctor – her Doctor – had arrived that evening, she'd felt fine for hours and didn't even think to mention it. After all, it was probably just a reaction to a bit of bad food. Stormcage wasn't known for its fine cuisine.
The next day, though, it was the tomato soup at lunch that did her in. "Doctor Song?" the guard asked, returning with her cleaned wastebasket.
She was lying on her narrow cot, her stomach still rolling threateningly. "Yes?"
"I need to bring you to the infirmary."
As she was in no condition to argue, she just nodded, got slowly to her feet, and followed the guard from the cell.
-o-o-o-o-o-o-
Under the circumstances, she wasn't really surprised. Well, surprised beyond the simple fact it was even possible. Which she'd rather doubted given the differences in their basic biology. Apparently, though, given her mutated DNA, they were close enough.
She wassurprised, however, when the Doctor showed up a few hours later and announced, without preamble, "You're pregnant." She was even more surprised later when she realized he wasn't her Doctor. Though, thinking about it, maybe she really ought not to have been.
-o-o-o-o-o-o-
Her Doctor did arrive later that afternoon, materializing silently and invisibly in a corner of her cell. He looked up from the console as she entered the TARDIS. "Hullo."
She tried to smile, but was too tired to give the expression real warmth. "Hello, sweetie."
"You okay?" he asked as she joined him up at the controls.
She nodded. "Yeah."
He cocked his head to one side, examining her closely, "No," he decided after a minute. Reaching out, he pulled her to him. "But you will be, River. Eventually. I promise." His words whispered through her hair as his hand stroked her back; she relaxed against his chest.
"You already know – ? " she began, but he cut her off.
"Spoilers," he warned. Then he continued after a pause, "Though I can tell you it was necessary... absolutely necessary... for things to work out this way. If that helps."
She pulled back a little to look up into his face as she asked, "Can you tell me why?"
"Not completely. But I can tell you that it's only because I knew we'd already had a child that I thought, before Utah, that our time together was through. That you'd believed I was dead all this time, deceived like everyone else. Which means it wouldn't have been there on that tower that I finally realized you'd only been playing a murderer; that you'd known I was alive the whole time. Which is when I did the only thing possible, dearest...I married you." He paused, letting her see his love, and his awe at the depth of her love, clear across his features. Shining in his eyes. "So, you see, without that, everything would have changed. As for the rest... Well..."
This time, her smile was quick and sure as she answered, "Spoilers?"
He returned her grin. "Yeah."
"I do have one more question," she continued, attempting to hold a straight face.
"Yes?"
"Does it ever bother you, sweetie, that you'll never really know whose child it is?" She couldn't help but laugh at his momentary confusion. "Yours...? Or his?"
It wasn't until much, much later though, as she stood over a cot with their daughter's name carved into it and watched him fall in love with her, that River finally really understood the rest. And knew how right he'd been.