An intravenous catheter should also be started to administer fluids, medications, and blood productsThere are several different types of uterotonic drugs that may be given, and the each has its own advantages and disadvantages. Moreover, the use of combination uterotonic therapy is a common practice and might be more effective at controlling bleeding than monotherapy. Some combinations might include oxytocin plus misoprostol, oxytocin plus ergometrine, and carbetocin.Medications used for PPH include the following:
Oxytocin (Pitocin) Stimulation of oxytocin receptors in the uterine muscle leads to contractions. The number of these receptors increases during pregnancy and with labor. There are also more in the fundus than in the lower uterine segment. Oxytocin has a quick onset of action, within a few minutes, but also loses effectiveness quickly because of a short half-life. The medicine is given in a rapid infusion and may cause hypotension. Oxytocin alone is the usually treatment of atony in the US. However, if bleeding is uncontrolled  after administration of oxytocin, then a second uterotonic is given. Carbetocin: A synthetic analog of oxytocin, works similarly to oxytocin but the half-life is much longer. It binds to smooth muscle receptors of the uterus, like oxytocin and has been reported to produce a stable uterine contraction, followed by rhythmic contractions. It is not available in the US but is available in many countries for the prevention of uterine atony and hemorrhage. Methylergonovine: This is an ergot alkaloid and has multiple mechanisms of action to induce fast, regular uterine contractions which leads to sustained uterine contraction.
Uterine atony is the failure of the uterus to contract adequately following delivery. Contraction of the uterine muscles during labor compresses the blood vessels and slows flow, which helps prevent hemorrhage and facilitates coagulation. Therefore, a lack of uterine muscle contraction can lead to an acute hemorrhage, as the vasculature is not being sufficiently compressed. Uterine atony is the most common cause of postpartum hemorrhage, which is an emergency and potential cause of fatality. Across the globe, postpartum hemorrhage is among the top five causes of maternal death. Recognition of the warning signs of uterine atony in the setting of extensive postpartum bleeding should initiate interventions aimed at regaining stable uterine contraction. Risk factors
There are many risk factors for uterine atony and several are due to the type of labor a mother experiences such as prolonged labor, labor lasting less than 3 hours, uterine inversion, the use of magnesium sulfate infusions, and extended use of oxytocin. Uterine distention caused by things like more than one fetus present, polyhydramnios, fetal macrosomia, uterine fibroids, chorioamnionitis can also lead to decreased uterine function and atony. Retained placental tissue or placental disorders, such as an adherent placenta, placenta previa, and abruption placentae increase the mothers risk of PPH. Body mass index (BMI) above 40 and coagulopathies are known risk factors.Magnesium sulfate is used often in patients with preeclampsia and eclampsia, can inadvertently inhibit uterine contractions. In addition, preeclampsia can lead to blood disorders such as  thrombocytopenia, platelet abnormalities, and disseminated intravascular coagulation.