For birth control, what's old is new again

(CNN)"I can't afford to get pregnant," says 25-year-old Aisha Mukooza.

So every morning, for the past two and a half years, Aisha's been strict about taking her temperature as soon as her alarm goes off at 6 a.m.

"I have my thermometer under my pillow. I take it, and then take the reading and put it in Kindara," Mukooza says.