CHANGES IN BONE MASS AS DETERMINED BY ULTRASOUND AND BIOCHEMICAL MARKERS OF BONE TURNOVER DURING PREGNANCY AND PUERPERIUM - A LONGITUDINAL-STUDY

In a longitudinal study, we analyzed the speed of sound (SOS) and broa dband ultrasound attenuation (BUA) of the os calcis as an index of bon e mineral density (BMD) to define the effects of pregnancy and lactati on on bone metabolism. We used an ultrasound bone densitometer and mea sured 6 biochemical markers of bone turnover in 18 healthy women throu ghout pregnancy and puerperium. The measurement of SOS and BUA by such an ultrasound device was clinically advantageous; not only is it radi ation-free technology, but it also correlates highly with BMD measured by conventional X-ray bone densitometry. While a significant decrease in SOS was found in the 3rd trimester of pregnancy as compared with t he early stage of pregnancy, there was no difference in both SOS and B UA between the breast-feeding women and the principally formula-feedin g women during a 6-month period of puerperium. The analysis of biochem ical markers revealed that both bone formation and bone resorption wer e elevated in the 3rd trimester of pregnancy as well as during puerper ium, and that the breast-feeding women had significantly higher bone m etabolism than the principally formula-feeding women. These results in dicate that bone mass decreases as bone turnover itself is enhanced du ring pregnancy, while lactation does not substantially affect bone mas s during at least 6 months of puerperium, although bone turnover is ac tive.