Maternal ultrasound bone density in normal pregnancy.

OBJECTIVES

The aim of the study was to investigate the effect of pregnancy on maternal bone mineral density by an ultrasound device.

STUDY METHODS

Two hundred and thirty consecutive healthy pregnant women were evaluated by ultrasound densitometry during the 1st (n=45), the 2nd (n=56) and the 3rd (n=129) trimester of pregnancy, measuring the velocity (SoS) and frequency attenuation (BUA) of an ultrasound wave as it passes through the os calcis. Speed of sound (SoS) and Broadband Ultrasound Attenuation (BUA) values are combined in order to express a relational variable (Stiffness), indicator of bone quality.

RESULTS

Statistically significant reductions in SoS, BUD and Stiffness values were observed during the 3rd trimester vs the 1st and the 2nd trimesters. Negative statistically significant relations were found between the gestational age and ultrasound densitometry parameters.

CONCLUSION

A linear reduction of ultrasound bone density was observed throughout pregnancy, reaching a statistical significance in the 3rd trimester, when the greatest calcium transfer from the mother to the fetus occurs.