Reporters loathe writing about anniversaries, but there was something intriguing about this weekend's 40th anniversary of the nurse-midwife unit at Hennepin County Medical Center.

HCMC leaders report remarkable success, with the unit providing natural and alternative strategies for 21,500 births (and counting) that some traditional hospital delivery units have shunned until recently. And yet -- despite being in a hospital industry that is notorious for copying anything that works -- the HCMC unit remains the only one of its kind in the nation.

"This unit is the best kept secret," said Rita O'Reilly, director of HCMC's nurse-midwife service.

The nine-bed unit was created in 1976 along with the new HCMC campus (then General Hospital). Homebirth advocates wanted the hospital to create a service that assisted with more births outside of hospitals, but the OB chief at the time wasn't comfortable with that, O'Reilly said. He instead proposed a unit to promote alternative and natural birthing strategies within the hospital -- one that offered single suites for labor and delivery where women could also recover with their babies. It was a departure from hospitals at the time that moved women through separate triage, labor, delivery and recovery rooms, and whisked newborns away to nurseries.

Many women in traditional units at the time "had legs in stirrups for deliveries and were strapped down with leather straps so they couldn't help out in any way," O'Reilly said.

The birthing philosophy at many hospitals has changed dramatically in recent years. Many hospitals now offer all-in-one birthing suites for women and have increased access to nurse-midwife services and alternative strategies to medication for managing labor pain. Abbott Northwestern Hospital just hosted its first waterbirth earlier this month, and is planning a suite specifically for waterbirths in the new birthing center it is building in partnership with Children's Hospitals and Clinics of Minnesota. (Midwifes now account for 10 percent of births in Minnesota, compared to less than 5 percent in 1990, according to federal VitalStats data.)

That is probably one reason why the HCMC unit remains a novelty in the U.S., because many hospitals are simply incorporating its philosophies into their main delivery units. Even if no other hospitals are copying HCMC, O'Reilly still believes in the benefits of a separate unit in the hospital that preserves its natural birthing approach for low-risk pregnancies. (She noted that about one in 10 deliveries end up taking place in the main HCMC delivery unit due to unexpected complications.)

"Sometimes you just get caught up in the pace of a different kind of a unit," she said. "If you're practicing with people who (prefer to use medical interventions) or have more high-risk deliveries, you may kind of start leaning that direction too."