MCQ Obstetrics Answer 30

The correct answer is A.

This patient has the findings most consistent with uterine hyperstimulation-more than 5 contractions in 10 minutes, contractions lasting 2 minutes or more, or contractions of normal duration occurring within 1 minute of each other and a non-reassuring fetal heart rate tracing.

Oxytocin is one of the most frequently used medications in the U.S. It is very effective at producing contractions and used very often for induction of labor. The most common adverse effect with oxytocin is a non-reassuring fetal heart rate pattern brought about by uterine hyperstimulation. Because it has a very short half-life (3-5 minutes), discontinuing the oxytocin often resolves the hyperstimulation quickly.

In this patient, with a bradycardia to the 80s, this step is most appropriate. In situations where the fetal heart rate tracing is not as non-reassuring, the oxytocin dosage may be reduced rather than discontinued completely.

If uterine hyperstimulation induced by oxytocin does not respond to shutting the oxytocin off, one can start magnesium sulfate (choice B) or give terbutaline. Both of these may be given intravenously to treat uterine hyperstimulation that does not respond to other measures.

To perform forceps-assisted (choice C) or vacuum-assisted (choice D) vaginal delivery would be contraindicated. This patient's cervix is only 6 cm dilated. Forceps and vacuum are not used unless the cervix is fully dilated.

To perform a cesarean delivery (choice E) would not be appropriate prior to trying other steps. This fetus most likely is not suffering a metabolic acidemia, based on the fact that its reassuring heart rate tracing is in the 120s and reactive. Its bradycardia is directly related to the hyperstimulation, which is caused by the oxytocin.

Thus, efforts should be made to manage the fetal distress with conservative measures prior to resorting to cesarean delivery.

Category: Obstetrics MCQs