Prevalence and risk factors of hypocalcemia among pregnant and non-pregnant women in Maiduguri, Nigeria: A cross-sectional study

Background: Pregnancy is a period of heightened calcium demand necessary for the optimum growth and development of the fetus and placenta. Women with low calcium intake may manifest with hypocalcemia in pregnancy. Objective: The aim of this study was to determine the prevalence and risk factors of hypocalcemia among pregnant and non-pregnant women in Maiduguri, Nigeria. Subjects and Methods: A comparative cross-sectional study was conducted at the University of Maiduguri Teaching Hospital, Maiduguri from 1st January 2017 to 31st December 2018. For each patient, sociodemographic and clinical characteristics were noted. Serum calcium, phosphate, total protein, and albumin were determined using spectrophometric methods with their specific reagents. The data obtained was analyzed using the SPSS statistical software for windows version 20. Chi-square test, Student t-test and ANOVA were used as appropriate. Odd ratio with multiple logistic regression was used to determine risk factors for hypocalcemia. P value < 0.05 was considered statistically significant. Results: A total of 1,500 (1,000 pregnant and 500 non-pregnant) women were analyzed. The mean age, total protein, and albumin were similar in the pregnant and non-pregnant women. However, the non-pregnant women were of higher parity than the pregnant women (3.75 +/- 2.79 versus 2.45 +/- 2.24, P < 0.001). The staple food of both group were mainly high carbohydrate diets. The prevalence of hypocalcemia was 29.20% among the pregnant women and 14.20% among the non-pregnant women (X2 = 64.34, P < 0.001). The mean serum calcium was lower among the pregnant compared to the non-pregnant women (2.08 +/- 0.22 mmol/L versus 2.2 +/- 0.19 mmol/L, F = 5.73, P = 0.02). There were no statistically significant differences in the mean serum calcium across the trimesters of pregnancy (F = 1.58, P = 0.21). Conclusion: Hypocalcemia in pregnancy is common in our environment and it is associated with anemia in pregnancy, anorexia, and primigravidity while attainment of at least basic education is protective. We recommend routine calcium supplementation in pregnancy and preconception period.