Up to 70 percent of hysterectomies in the United States, a quarter of knee replacements in Spain and more than half the antibiotics prescribed in China are inappropriate, over-used health care, researchers said on Monday.

Experts who carried out a series of studies across the world found that medicine and health care are routinely both over- and under-used, causing avoidable harm and suffering and wasting precious resources.

The studies, commissioned by The Lancet journal and conducted by 27 international specialists, also found rates of Caesarian section deliveries are soaring — often in women who do not need them — while the simple use of steroids to prevent premature births has lagged for 40 years.