House de-elevators and finds Cuddy sitting outside his office holding his cane. She hands it back to him and House inspects it for booby-trapping before welcoming "Little Little Greg" back. He tosses the substitute cane in a nearby mail cart and takes a seat next to Cuddy. Cuddy says that House is who he is, and the fact that she can't be with her daughter isn't really his fault. She's sorry. House points out that it's not like Cuddy was any good at her job before she got the baby and that her rapid mood swings most likely mean that she's on her period. That seems like a weird thing for House to say until you realize that he has to say it in order to have his epiphany moment. He stops in mid-sentence and takes off, but Cuddy doesn't realize what's going on so she follows him down the hallway wondering why when she's a jerk, he acts like a human, but when she's human, he acts like a jerk. She thinks that's his way of accepting her apology. He denies it, saying he's just saying that she sucks at her job and will continue to do so a bit more now that she has a baby. Cuddy accuses him of playing a part, and House tells her to go hang out with Wilson and do some more psychoanalyzing while House saves Dana's life.
House enters Dana's room and looks in the garbage. He finds an empty box of maxipads and holds it aloft on his cane. Kumar asks how that's diagnostically relevant. House says Dana is bleeding out of her uterus. "Women do that. It's perfectly natural, not scary at all," Taub says. Easy for you to say, Taub. House points out that Dana's uterus and her vascular tumors are bleeding at the same time. It could be a coincidence, or it could be a case of ectopic endometriosis. It turns out that when the surgeons operated on Dana's uterus, they sent endometrial cells into Dana's bloodstream. They landed in various places in her body and multiplied for eight months to grow big and strong. Then, when Dana was getting her period, the masses swelled at the same time as her uterus, causing her various liver, spine, and lung problems. And then when she got her period and started to bleed, they bled, too. "Yes, ladies," House tells the viewing audience; "I am blaming her period. Granted, it's the worst period ever." He adds that it has a lot of competition. Sigh. Doesn't it, though? Am I right, girls? House recommends waiting until Dana's period is over and the bleeding stops and simply cutting the masses out. That sounds fine, except that a few scenes ago Taub was saying that Dana might not last the day with the rate she was bleeding. Oh, well. House just prescribes a pint of ice cream and a DVD of Beaches. Ignorant man! We eat ice cream when we've been dumped. We eat chocolate during our periods.