Fetal Position is the seventeenth episode of the third season of House and the sixty-third episode overall.
Pregnant photographer Emma Sloan (Anne Ramsay) arrives at a photo shoot for rock star Tyson Ritter, but she can't read the writing on a prop chalk board. She starts slurring her speech and says she's having a stroke before passing out.
House comes in to visit Emma, who is checked in at the hospital. He runs some tests and determines her kidneys have shut down, and resolves to find the underlying cause of the stroke. Emma is interested in taking photos of House, and the staff is interested in House's photo. House has the staff run tests to determine if she has a clot in her heart, while he discusses his vacation plans. Cameron wonders why House didn't say anything about seeing her and Chase together. They confirm House's diagnoses and prepare to put in a balloon to clear the clot.
The staff clears the clot but Emma's kidneys are still shut down and the staff runs through various diagnoses. They come up with five possible conditions but they all test negative. House confronts Emma and warns that there's something wrong with the fetus.
It's back to the white board where House explains that Emma has a condition known as Mirror syndrome, meaning that the fetus is dying and could take the mother with it. The team decide to check the fetus's heart except they can't get a clear MRI because it won't stay still. House decides to paralyze the fetus and Cuddy confronts him about it. She is told by House that Cameron and Chase are having sex in the hospital, then agrees to let House get Emma's consent and accompanies him. Emma agrees and Cuddy reassures her that House is the best person to handle the situation. The subsequent tests show the bladder is four times its normal size because of a urinary tract obstruction and Cuddy takes over the case. She talks to Cameron about her dating Chase and warns that Chase won't be the one who gets hurt.
Cameron finds House relaxing in a hypobaric chamber in an attempt to build up his tolerance for high altitude (by reducing the pressure in the chamber), for his upcoming vacation. Cameron confronts him about telling Cuddy about her and Chase. He ducks the matter while Cuddy tells Emma about the treatment they have planned to relieve the pressure on the fetus' bladder. Cuddy then finds House in her office where he questions her diagnosis of bladder blockage, warning the first two tests will be inconclusive. He suggests that Cuddy is sympathizing with Emma as they are both older women having a baby through artificial insemination. Cuddy decides to hand the case back to House.
The third test proves positive and Chase gives the results to Emma, who is thankful things will turn out okay. Emma notices that Chase is in love with Cameron. The doctors prepare to treat the baby but discover that Emma is jaundiced and her liver is shutting down. House believes the fetus "lied" and the urinary tract obstruction is just a sign of something else. With time running out, House suggests there is only one sure cure: to abort the baby at 21 weeks. House breaks the news to Emma and she wants to wait the two weeks, but House warns she won't last two days. She refuses to have an abortion and demands House fix it so they can both live.
House goes to Cuddy who refuses to go to Emma. It's back to a differential diagnosis with Cuddy running the board. Cuddy suggests that they go through the veins in the neck to get to the liver. House mentions Cameron and Chase are dating, much to Foreman's surprise. They go with it while Cuddy suggests that an unenthusiastic House go on vacation. Chase and Foreman go ahead with the procedure, however, but fetus' heart rate drops and Emma goes into pre-term labor. They manage to stop the contractions, but warn they'll have to remove the fetus. Cuddy insists on finding the problem and suggests they have to check the undeveloped lungs. Cuddy suggests they use steroids to increase the lung growth, yet the staff refuses. Cuddy goes off to do it and Emma has another seizure. Wilson goes in to suggest it's time to terminate and Cuddy tells him to either help or get out.
Later, a concerned Cuddy goes to Wilson and admits that everyone was right all along and Emma's lungs are shutting down. She asks him what House would do if he was in her position, and Cuddy concludes that Emma doesn't need her lungs because she's on a respirator anyway, so she's put the fetus back on steroids. Cuddy goes to House's apartment while he is packing up for his vacation and agrees to look at the tests now that the baby's lungs have expanded. They go back to the hospital and try to figure out a way to examine the lungs more thoroughly. They finally decide to do exploratory surgery and explain things to Emma. She agrees and they take her into surgery where House performs the operation.
During the operation, the baby's hand emerges weakly and grasps House's index finger. House, in response, pauses for a moment, reacting by touching the tiny hand with his thumb. House stares at the phenomenon in awe, but Cuddy reminds him to proceed, and he snaps back to reality. They find lesions in the baby's lungs but Emma goes into ventricular fibrillation. House prepares to cut the umbilical cord but Cuddy insists on applying the paddles until Emma is revived, once threatening to electrocute House. Cuddy succeeds, allowing Emma and her son to live.
House informs Emma that the baby is now fine and Emma thanks him. House tells her to thank Cuddy rather than him because he would have killed the kid. Chase meets with Cameron who notices a photo that Emma took of him, one that shows him "glowing," from earlier when he was looking at a picture of Cameron. Cuddy gives House a ticket for a vacation to Vancouver Island and he tells her she made the wrong call and got lucky. Cuddy is fine with her decision and tells him to go get happy. House goes home and rips up the ticket, then takes the phone off the hook and settles down for a night of television and Vicodin. He is deep in thought as he stares at the finger where the baby touched him.
It is implied that great deal of time passed between the last two scenes of the episode. The episode states that at the time of her hospitalization, Emma was 21 weeks (5 months) pregnant, but the final scene of the episode showed her at her home, hanging up photos of Cuddy and House's staff (though not of House himself) and caring for her newborn son, who she has named Greg, after Dr. House. If, after she left the hospital, Emma carried the child to term (nine months), then the episode jumped about four months into the future.
The camera that Emma uses while at Princeton-Plainsboro is a Canon EOS-1Ds Mark II with an attached Canon EF 24-70mm f/2.8L lens minus the hood. Later, Cameron is seen packing her gear into a Porta Brace CS-DV2 case normally used for consumer Mini-DV video cameras.