A multiparous patient at 38 weeks gestation with a history of poorly controlled asthma and chronic hypertension is admitted for induction of labor. Her cervical exam is 4 cm dilated, 80% effaced, and at -1 station. Fetal heart rate monitoring is reassuring. Following a successful vaginal delivery of a macrosomic infant, the patient develops heavy vaginal bleeding consistent with uterine atony. The physician must select an appropriate uterotonic agent while avoiding exacerbation of her underlying conditions. Match the following medications considered for postpartum hemorrhage to their distinct pharmacological properties, adverse effects, or absolute contraindications.
- MethylergonovineAn ergot alkaloid that induces smooth muscle tetany; strongly contraindicated in patients with preeclampsia or chronic hypertension.
- Carboprost tromethamineA prostaglandin F2-alpha analog; contraindicated in patients with asthma due to its potential to cause severe bronchospasm.
- MisoprostolA prostaglandin E1 analog; frequently causes transient maternal pyrexia, diarrhea, and shivering shortly after administration.
- OxytocinA nonapeptide that has structural similarities to vasopressin; can cause severe hyponatremia and water intoxication when administered in large volumes.
Answer
Methylergonovine matches the ergot alkaloid contraindicated in hypertension. Carboprost matches the prostaglandin contraindicated in asthma. Misoprostol matches the prostaglandin causing transient pyrexia. Oxytocin matches the nonapeptide causing water intoxication.
Each uterotonic agent has a distinct mechanism and side effect profile that dictates its clinical use and absolute contraindications. Methylergonovine causes vasoconstriction (avoid in hypertension). Carboprost causes bronchoconstriction (avoid in asthma). Misoprostol causes transient pyrexia and diarrhea. Oxytocin has an antidiuretic effect (risk of water intoxication).
Step-by-Step Solution
Key Concept
Pharmacologic management of postpartum hemorrhage relies on selecting uterotonic agents while avoiding absolute contraindications based on the patient's medical history (e.g., asthma, hypertension).
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