Elisabeth Bing, co-founder of Lamaze International who popularized what was known as natural childbirth and changed how women and doctors approached the delivery room, died Friday in her New York apartment at the age of 100.  The cause of her death wasn't immediately known.

When Bing became interested in childbirth techniques in the 1950s, women went into the delivery room with far less information than they do today, the dads were generally stuck in the waiting room and the women were heavily medicated.

Bing, who was trained as a physical therapist, taught breathing and relaxation techniques to generations of expectant mothers, wrote several books about pregnancy and birth, and encourage both women and men to be more prepared and be more active participants in the birth of their new babies.

"I was certainly considered a radical," she wrote in Lamaze's magazine in 1990. By then, she noted, childbirth education had become common. "This so-called fad has been proven not to be a fad."

Born on July 8, 1914 in Berlin, Bing fled Germany when the Nazis rose to power with her family and headed to England where she received her physical therapy training.  Working with new mothers got her thinking about delivery practices, an interest that she carried with her after she moved to the United States in 1949.

She learned about ideas advanced by some doctors, such as French obstetrician Dr. Fernand Lamaze, for using breathing and mental preparation to manage the pains of labor without the need for medication.  She and the late Marjorie Karmel established what is now known as Lamaze International in 1960 to spread the strategies. 

Lamaze went on to become a household name.  Its signature classes involve both women and men, with the idea that fathers could provide both emotional and mental support during labor.  Still, the idea of refusing painkillers fell out of favor with many women, and some couples began to look for shorter birth preparation classes than Bing's six-week program.

Despite the change, Bing still felt she had changed the birth process for the better.  "I feel we have changed the whole attitude toward obstetrics and pregnant women, not necessarily technical changes, but the psychological and practical approaches to pregnancy," she told The New York Sun in 2004.

Today, Lamaze International has about 2,000 childbirth educators around the globe and now more broadly promotes healthy and natural birth practices and preparation.  President Robin Elise Weiss said on Saturday that Bing's influence remains in delivery rooms around the country.

"Even if people haven't heard her name," Weiss said, "she's impacted how they give birth."