Bone density in a population of long term oral contraceptive pill users does not differ from that in menstruating women.

Prevention of osteoporosis is a major public health issue. Amenorrhoeic women have lower bone density than normally menstruating women, which is related to the duration of amenorrhoea and the severity of oestrogen deficiency. Bone mineral density (BMD) in amenorrhoeic women can be improved by oestrogen replacement in the form of the combined oral contraceptive pill (COCP), so increased BMD might be an important non-contraceptive benefit of the COCP in menstruating women. Previous studies have been variably reported, but have used different methodologies for measurement of BMD. We measured BMD using the DEXA technique in long term COCP users and compared this with menstruating women who had never used the COCP. No differences in bone density were found, suggesting that the COCP does not improve bone mass in menstruating women who are adequately oestrogenised by their own ovaries.