Katy Lu opened the front door of the two-story house near the Queens Botanical Garden. “Why don’t I show you the babies first?” she said in Mandarin Chinese, leading the way up a staircase and past a small kitchen where a rice cooker sat on a table.

A dozen bassinets lined the walls of the warm, low-lit nursery where two babies slept and a woman tended to a third at a changing table. Blankets in some of the empty bassinets suggested that other newborns would spend the night here as well.

Across the hall, an open door offered a view of a double room, with one woman sitting up in her bed and another lying under a blanket. The women, both new mothers, were there for the Chinese practice of postpartum confinement — called zuo yuezi, or, in Mandarin, sitting the month.

To Western ears, confinement sounds like something out of a Victorian novel, but in some traditional Asian cultures, women still spend the month after a baby’s birth in pampered seclusion. Typically, a woman’s relatives would care for her, but more recently, the practice has been outsourced to postpartum doulas and confinement centers, like the one Ms. Lu operates. In the United States, they cater to middle-class immigrant women separated from their families. Business is steady enough in New York City to support at least four postpartum centers, tucked away in the heavily Asian-immigrant neighborhoods of Flushing and Bayside, Queens.