Objective : The goal of this study is to find a link between the amount of calcium in the blood and how stiff the uterus is and how much blood is lost in women who are in the first and second stages of labour. Methods : Study design is cross sectional study in department of Obstetrics &   Gynaecology  Beni-suif University Hospital, Duration of  study is from July 2021 till November 2021. Number of subjects studied: 180 women, with intrapartum estimation of serum calcium level and relationship to atonic primary PPH after vaginal delivery or caesarian delivery. Atonicity is characterised by a soft, swollen uterus and a lack of muscle tone. Results : 180 clients in total were looked at. 45 women who had a calcium level in their blood that was less than 8 mg% developed uterine atonicity. Only five of the women who had a serum calcium level of more than 8 mg% had uterine atonicity. Conclusions: Our results showed that, reduced calcium level is strongly linked to uterine atony and is therefore a risk factor for it.