As her labor progressed, Jaime St. Peter went to her roof deck for some fresh air. In between contractions, her midwife fed her yogurt as cars whizzed past on the nearby Brooklyn-Queens Expressway. During contractions, Ms. St. Peter would clutch the deck's railing because, she said, "it felt very good to squat and hang."

After 38 hours of active labor—spent outside, in a kiddie pool set up in the dining room, and walking the stairs of her Brooklyn Heights duplex—Ms. St. Peter, her husband by her side, gave birth on the bed to a 7-pound-6-ounce son.

"It's one of the things I'm proudest of in my life," Ms. St. Peter, a 34-year-old attorney, said of giving birth without pain medication to her now 2-year-old son. "I wish women wouldn't shy away from the difficulties of giving birth because I do feel like it's important for preparing yourself to mother: the fear, the pain, the work of it."

Ms. St. Peter is among a growing number of New York residents choosing to give birth at home. Home birthrates nationally, while still less than 1% of total deliveries, have climbed quickly—rising 50% between 2004 and 2011, according to U.S. Centers for Disease Control and Prevention data provided to The Wall Street Journal. And the increase has been even more dramatic in New York state, where home births have grown 71% since 2004. Statewide, there were 2,130 home births in 2011.

But a home birth in New York City—where neighbors live cheek-by-jowl, often in small walk-up apartments—poses unique challenges not faced in, say, rural Tennessee, where home-birth maven Ina May Gaskin started her practice. Will neighbors hear screaming through labor pains? Will creaky floorboards give way under the weight of the birthing pool? How does a laboring mother get down four flights of stairs, in case of a hospital transfer?