One versus two uterotonics: Which is better for minimizing postpartum blood loss?

Ergonovine plus oxytocin

Ergonovine is an ergot derivative that causes uterine contractions and has been shown to effectively reduce blood loss at delivery. In the United States a methyl-derivative of ergonovine, methylergonovine, is widely available. In a meta-analysis with mostly vaginal deliveries, there were no significant differences for ergonovine plus oxytocin versus oxytocin alone for the following outcomes: death, intensive care unit admission, rate of blood loss ≥ 1,000 mL(2.0% vs 2.7%), blood transfusion, administration of an additional uterotonic, change in hemoglobin from pre- to postdelivery, nausea, hypertension, shivering, and fever.³ However, ergonovine plus oxytocin, compared with oxytocin alone, resulted in a significantly reduced rate of blood loss ≥ 500 mL (8.3% vs 10.2%) and an increased rate of vomiting (8.1% vs 1.6%).³ In these trials women with a blood pressure ≥ 150/100 mm Hg were generally excluded from receiving ergonovine because of its hypertensive effect.

Clinical practice options

Given the Cochrane meta-analysis results, ObGyns have two approaches for optimizing PPH reduction.

Option 1: Use a single uterotonic to reduce postpartum blood loss. If excess bleeding occurs, rapidly administer a second uterotonic agent. Currently, monotherapy with intravenous or intramuscular oxytocin is the standard for reducing postpartum blood loss.^5,6 Advantages of this approach compared with dual agent therapy include simplification of care and minimization of AEs. However, oxytocin monotherapy for minimizing postpartum bleeding may be suboptimal. In the largest trial ever performed (involving 29,645 women) when oxytocin was administered postpartum, the rates of estimated blood loss ≥ 500 mL and ≥ 1,000 mL were 9.1% and 1.45%, respectively.⁵ Is 9% an optimal rate for blood loss ≥ 500 mL following a vaginal delivery? Or should we try to achieve a lower rate?

Given the “high” rate of blood loss ≥ 500 mL with oxytocin alone, it is important for clinicians using the one-uterotonic approach to promptly recognize patients who have excessive bleeding and transition rapidly from prevention to treatment. When PPH cases are reviewed, a common finding is that the clinicians did not timely recognize excess bleeding, delaying transition to treatment with additional uterotonics and other interventions. When routinely using oxytocin monotherapy, lowering the threshold for administering a second uterotonic (methylergonovine, carboprost, misoprostol, or tranexamic acid) may help decrease the frequency of excess postpartum blood loss.

Option 2: Administer two uterotonics to reduce postpartum blood loss at all deliveries. Given the “high” rate of excess postpartum blood loss with oxytocin monotherapy, an alternative is to administer two uterotonics at all births or at births with a high risk of excess blood loss. As discussed, administering two uterotonics, oxytocin plus misoprostol or oxytocin plus ergonovine, has been reported to be more effective than oxytocin alone for reducing postpartum bleeding ≥ 500 mL.³ In the Cochrane meta-analysis, per 1,000 women given oxytocin following a vaginal birth, 122 would have blood loss ≥ 500 mL, compared with 85 given oxytocin plus misoprostol or oxytocin plus ergonovine.³

Misoprostol is administered sublingually, buccally, or rectally, and methylergonovine is administered by intramuscular injection. Although dual uterotonic therapy is more effective than monotherapy, dual therapy is associated with more AEs. As noted, compared with oxytocin monotherapy, the combination of oxytocin plus misoprostol is associated with more nausea, vomiting, shivering, and fever. Oxytocin plus ergonovine is associated with a higher rate of vomiting than oxytocin monotherapy. In my practice I prefer using intramuscular methylergonovine as the second agent to avoid the high rate of fever associated with misoprostol.

For dual agent therapy, one approach is to administer misoprostol 200 µg or 400 µg through the buccal^7,8 or sublingual^9,10 routes. Higher dosages of misoprostol (600 µg to 800 µg) have been used^11,12 but are likely associated with higher rates of nausea, vomiting,shivering, and fever than the lower dosages. Methylergonovine 0.2 mg is administered intramuscularly.

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