Evaluation of calcium and phosphorus elements in the developing human fetal long bone at different trimesters of pregnancy

Recent bone research has emphasized the importance of mineral composition and peak bone mass during the fetal and postnatal periods, impairment in which are related to subsequent bone diseases in later life. However, there is no quantitative data on the variations in the composition across the growth period of fetal bone to gain better insight into the fetal origin of adult bone disorders and old-age bone diseases. This study analyzed the mineral composition of the developing humerus bone in different trimesters of pregnancy. Stillbirth or medically terminated human fetal specimens ranging from approximately 10-36 weeks were obtained after institutional ethical committee clearance. The transverse section of each humerus close to mid-diaphysis was subjected for mineral analysis by scanning electron microscopy and energy dispersive spectroscopy techniques. The results indicated that the calcium (Ca) noticeably varies between 10 and 20 weeks and 24 and 36 weeks. It is also noted that the mean phosphorus level remained constant from 12 to 36 weeks. Further, significant differences were observed in Ca to phosphate ratio at different gestational weeks. The study provides preliminary quantitative insight into fetal cortical bone mineral composition and may serve as a foundation for future investigations examining broader anatomical regions, significance of mineral constituents, and functional correlations.