One reason for the change, it seems, is “The Business of Being Born,” a documentary produced by the actress and former talk show host Ricki Lake, which ran in only a few theaters during its theatrical release in January but has become an underground hit among expectant parents since coming out on DVD. (Rentrak, a company that monitors DVD rentals, said that instead of dropping off, as typically happens with new releases, the film is being rented at consistent rates.)

With scenes of several home births (including one in which Ms. Lake delivers her second child in the bathtub of her former West Village apartment), the film argues that women’s bodies are perfectly well equipped to give birth at home and that the occasion need not be a medical event.

Many women are wary of hospital births, both because of a patient’s limited control over the process and because of the growing frequency of Caesarean sections (use of the procedure increased by 50 percent nationwide from 1996 to 2006, to nearly one in three births, according to the National Center for Health Statistics).

“The Business of Being Born” seems to offer an alternative, and “is putting home births on the map in a way that makes women feel like it’s a really legitimate option,” said Élan V. McAllister, founder of Choices in Childbirth, a four-year-old nonprofit educational group that publishes “The New York Guide to a Healthy Birth.” “In your home you’re able to move around and be in the tub or in the shower. You’re able to eat and behave in a natural, more normal way. If you believe birth is not a medical emergency, it is the ideal place because it’s the place you can really let go and follow what your body wants you to do.”

Mrs. Scharback, for example, tried many different positions over the course of her labor: leaning on the windowsill of her newly decorated nursery, sitting on a birth stool, crouching on the bed, sitting on the toilet and, eventually, leaning back against her husband inside the warm birthing pool. Finally, having endured 40 hours of regular contractions with no painkillers  like most women who have home births, she refused them  she let out a guttural scream and pushed her new son, Noah, into the world.

Home birth also appeals to the desire of many new mothers to stay put, and in continual contact with their babies, after the grueling ordeal. Michelle Zassenhaus, 33, a Web designer and photographer who gave birth for the first time in March, said her apartment in Park Slope, Brooklyn, was an ideal environment for calm postpartum recovery with her husband, Silvio Galea, and their new daughter, Lucienne.

Shortly after the birth, “the doula and midwife got us all cleaned up, cleaned up the apartment, looked in our fridge, figured out what kind of food they could prepare for us, showed us some breastfeeding techniques, put us in bed, gave us some food, and left,” Ms. Zassenhaus said. “Those first couple of days when you’re usually suffering through postpartum, we were in this very quiet, intimate state of bliss.”