15 methyl prostaglandin F2α (carboprost tromethanine). Of all the prostaglandins used in the United States today, this 1 has the longest track record in managing uterine atony. Administer it into a peripheral muscle or directly into the uterus itself. In general, I prefer the first approach. If the patient is hypotensive, however, peripheral muscular perfusion will be diminished, and direct injection into the myometrium may be more effective.
One vial of 15 methyl prostaglandin F2α (PGFα) contains 250 μg. The medical literature suggests the use of 2 to 6 vials before considering the intervention a therapeutic failure.1 My own approach, generally, is to inject 2 vials initially in cases of serious uterine atony, then move on to other drugs if this proves ineffective. In most cases, however, it is entirely appropriate to repeat this 500-μg dose once or twice. (There is no evidence supporting the routine initial administration of 500 μg as opposed to 250 μg.) Patients generally respond within 5 minutes.
The primary contraindications to 15 methyl PGF2 α re asthma and cyanotic cardiac disease. Since this drug is a general bronchoconstrictor, clinically insignificant desaturation occurs in all women. Because asthmatic women are more sensitive to these bronchoconstrictive effects, the use of this agent in an asthmatic patient may have disastrous results. For the same reason, a woman with cyanotic heart disease—who may be only marginally oxygenated—might be unable to tolerate a degree of oxygen desaturation that would be insignificant in most patients.
Methylergonovine maleate. This drug has the longest history of use in the management of uterine atony. It is a potent smooth muscle constrictor, affecting not only smooth muscle of the uterus but vascular smooth muscle as well. In the vast majority of cases, the drug, dosed at 0.2 mg, should be given intramuscularly (IM). As with 15 methyl PGF2α, the patient generally responds within 5 minutes. Most physicians give 1 to 2 doses of methylergonovine at 5-minute intervals before abandoning the therapy. However, if the atony is slow, chronic, or intermittent, additional doses at longer intervals may be appropriate, as may oral therapy.
Because it may lead to hypertensive crisis and cerebral vascular accident, the drug is contraindicated in hypertensive patients.
Misoprostol. The most widely utilized agent in the world for both prevention and management of postpartum hemorrhage is misoprostol. It was not commonly used in the United States until recently, but is increasingly valued for its effects against postpartum atony. The drug comes in 100-μg pills. Although very small doses (25 μg) are used in labor induction, much larger quantities are needed for postpartum atony—generally in the range of 600 to 800 μg. Misoprostol is readily absorbed through any mucous membrane and may be given rectally, buccally, or orally, as the situation demands. (Avoid the vaginal route in patients with hemorrhage because the pills will wash out.)
While neither the obstetrician nor the patient wants to go from a normal spontaneous vaginal delivery to peripartum hysterectomy, such lifesaving decisions must occasionally be made.
Misoprostol generally takes effect within 10 to 15 minutes. There are no known contraindications to its use. In such high doses, however, violent shivering is a relatively frequent occurrence. This may be frightening for both patient and physician, but is transient and requires no treatment.
Surgery. When pharmacologic therapy fails, laparotomy is indicated. A number of surgical approaches to uterine atony have been described.3-5 Although some clinicians advocate uterine and hypogastric artery ligation, most series touting the effectiveness of these techniques do not include patients for whom medical management has failed.6 In my experience, these women are extremely unlikely to respond to either uterine or hypogastric artery ligation. Indeed, any technique that causes further ischemia of an organ would seem to stand little chance of improving the function of that organ and increasing contraction.
In most instances of failed medical management, hysterectomy is necessary. While neither the obstetrician nor the patient wants to go from a normal spontaneous vaginal delivery to peripartum hysterectomy, such life-saving decisions must occasionally be made. Death due to uterine atony alone is almost always preventable.
TABLE 2
Uterine atony: predisposing factors
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Lacerations
Genital-tract lacerations are the second most common cause of postpartum bleeding. When the palpated uterus is found to be firm in a hemorrhaging patient, a thorough search for lacerations is indicated. Begin this process with careful inspection of the vagina and cervix. Adequate anesthesia often is essential for such exploration. In some instances, it may be necessary to move the patient to the operating room (OR), as surgical assistance may be needed to obtain appropriate exposure.