The incidence of birth has been determined for each hour of the day for all births in Norway in 1968-1977 of fetuses of 16 weeks of gestation or older, with resident mothers. The 24-hour incidence variations of births (A) with spontaneous onset and parturition, (B) with spontaneous onset, but delivery intervention, (C) with induced onset, but spontaneous birth, and (D) with induced onset and delivery intervention, are all different. It is shown that the curve for the hourly incidence of birth category A coincides very well with previous results of other workers. When multiple births are excluded and category A is split into first and later births in Northern and Southern Norway, dissimilarities arise between the respective 24-hour incidence curves. The results indicate that the 24-hour birth incidence variation has an underlying endogenous, circadian rhythmicity - possibly synchronized by the sun. The 24-hour rhythmicities of birth categories B, C and D seem to be purely exogenous - reflecting the working activity rhythms of hospital obstetricians and midwives.
University of New Mexico, Albuquerque, New Mexico; the Uniformed Services University of the Health Sciences, Bethesda, Maryland; the Northern Navajo Medical Center, Shiprock, New Mexico; the Mid-Columbia Medical Center, The Dalles, Oregon; the University of Texas Rio Grande Valley, Edinburg, Texas; the Alaska Native Medical Center, Anchorage, Alaska; the University of Mississippi Medical Center, Jackson, Mississippi; the Oregon Health and Science University, Portland, Oregon; and the American College of Obstetricians and Gynecologists, Washington, DC.
Since 1970, the American College of Obstetricians and Gynecologists' Committee on American Indian and Alaska Native Women's Health has partnered with the Indian Health Service and health care facilities serving Native American women to improve quality of care in both rural and urban settings. Needs assessments have included formal surveys, expert panels, consensus conferences, and onsite program reviews. Improved care has been achieved through continuing professional education, recruitment of volunteer obstetrician-gynecologists, advocacy, and close collaboration at the local and national levels. The inclusive and multifaceted approach of this program should provide an effective model for collaborations between specialty societies and health care professionals providing primary care services that can reduce health disparities in underserved populations.