Pre-eclampsia (PE) and gestational hypertension (GH) are the main forms of Hypertensive Disorder of Pregnancy. Calcium (Ca) is involved in many body functions. Hypertension complicates 5% of all pregnancies and 11% of first pregnancies and half of these cases are associated with preeclampsia (gestational hypertension plus proteinuria). Calcium supplementation seems to be advantageous but currently it is only considered for patients with poor dietary intake and high risk for PE. This study has conducted to find the use of calcium supplementation in the risk reduction among the Preeclampsia women. The results demonstrated a positive association between 1500 mg calcium daily supplementation and reduction in risk of pregnancy loss among Libyan women who were at pre-eclampsia risk. The introduction of calcium supplementation in maternal health program is strongly recommended among Libyan population with low dietary intake of calcium. 1500 mg -2000 mg of calcium supplement are necessary to reduce the complications during the pregnancy among the women.