Calcium and Phosphorus Balance in Pregnant Women Attending Antenatal Care at Murtala Mohammed Specialist Hospital, Kano

Adequate calcium and phosphorus metabolism during pregnancy is essential for foetal skeletal development and maternal bone integrity. This study assessed calcium and phosphorus balance in pregnant women attending antenatal care at Murtala Mohammed Specialist Hospital in Kano, North West Nigeria. Ninety pregnant women across the three trimesters were recruited alongside 30 non-pregnant women of reproductive age as controls. Serum calcium, phosphorus, and parathyroid hormone levels were measured from venous blood using standard biochemical methods. Dietary calcium intake was estimated using a validated food frequency questionnaire. One-way ANOVA and Tukey post-hoc tests were applied for inter-trimester comparisons. Results indicated that serum calcium declined progressively across trimesters, with lowest values in the third trimester, while parathyroid hormone rose correspondingly. Serum phosphorus showed modest trimester-related variation. Dietary calcium intake was below recommended levels in 72 percent of participants. Third-trimester participants had the greatest calcium-intake insufficiency. The study concludes that calcium homeostatic mechanisms are physiologically stressed during pregnancy in this population, particularly in the third trimester, and that dietary calcium is inadequate for many women. Routine calcium supplementation, dietary education, and bone health monitoring during antenatal care in Kano are strongly recommended. Keywords: calcium, phosphorus, pregnancy, parathyroid hormone, Kano.