Art of attending women in childbirth. It is known to date to ancient biblical, Greek, and Roman times. It declined in the Middle Ages, when childbirth carried high mortality for mothers and infants, but advanced considerably in the 17th–19th century. Later, with advances in obstetrics and gynecology, most women gave birth in hospitals. In the 1960s, the natural childbirth movement, feminism, and other factors renewed interest in the personal care given by midwives. In the U.S., certified nurse-midwives (CNMs)registered nurses trained in midwiferyaccept only low-risk patients. If problems develop, a physician is called. CNMs also provide pre- and postnatal care and reproductive health advice. Lay midwives usually have no formal training, are unlicensed, and deliver (at home) about three-fourths of infants born throughout the world, mostly in developing countries and rural areas of developed nations.