Certified nurse midwife-attended births: trends in Washington State, 1995-2004.

Nationwide, the proportion of certified nurse-midwife (CNM)-attended births has increased steadily. We examined trends in CNM-attended singleton spontaneous vaginal births between 1995 and 2004 in Washington State by site of birth, payer source, and hospital birth volume. CNMs were more likely than other providers to care for women at risk for adverse outcomes based on several sociodemographic indicators.