Episode 89 of "Without a Trace"
s04e19 Expectations

The team searches for an HIV positive pregnant woman who vanished moments after she and her husband saw the ultra-sound of their healthy 8 ½-month-old fetus. The team members remain wary of Megan's husband, Brian, who allegedly left for a business trip after the ultra-sound. Their suspicions are heightened when they learn that he had a brief affair last year after Megan was diagnosed with HIV, which she contracted from a previous relationship. Brian admits that it's not easy for either of them to live with her HIV, but they're working through it and, after much thought, chose to start a family. He suggests questioning a blood technician who upset Megan by chastising her for putting her child at risk by choosing to become pregnant with HIV. They also investigate whether Megan's disappearance is connected to an attempted infant abduction at the same hospital three weeks prior and look into the relevance of her last incoming cell phone call from a detention center.