Ergometrime n oxytocine used together for postpasturm bleeding. but oxytocin causes vasodilation while erg. cause vasoconstrict?so how they work?

Oxytocin: Oxytocin is a hormone that produces intense contraction of the uterine muscle. By contracting the uterine muscles, the blood vessels that cause the bleeding also become contracted and the bleeding stops or is reduced.

Muscle contraction: The uterus is a remarkable organ. After stretching to an incredible size (from normal), it then contractss or tightens upon itself to close the large blood vessels developed during pregnancy to prevent excessive bleeding after childbirth. Oxytocin stimulates and enhances this contractile activity ergotamine also causes uterine contractions as well as blood vessel constriction, reducing bleeding.