B. IV fluids
C. Postdates pregnancy
D. Prostaglandin (PGE2) gel
E. Vaginal examination
The correct answer is d.
Prostaglandin (PGE2) gel is widely used for labor induction. In simple terms, it is used "to soften" an unfavorable cervix, to make the cervix more favorable for induction. It has been shown to lead to an improvement in the Bishop's score, a shorter duration of labor, a need for lower maximal doses of oxytocin, and a reduced incidence of cesarean deliveries. PGE2 gel can also cause uterine contractions. One of the major side effects with PGE2 gel is uterine hyperstimulation. This occurs when uterine contractions come one right after the other, or when there is a tetanic contraction (a prolonged uterine contraction with no rest period). In this setting, the fetus can become hypoxic with a resultant bradycardia. This patient had the gel placed and 60 minutes later had uterine hyperstimulation.
Infection (choice A) has not been shown to cause uterine hyperstimulation. This patient's group B Streptococcus colonization is likely noncontributory.
IV fluids (choice B), unless oxytocin is present, do not cause uterine hyperstimulation.
Postdates pregnancy (choice C) is the reason for this patient's induction and not likely the direct cause of her uterine hyperstimulation.
Vaginal examination (choice E) does not usually cause uterine hyperstimulation. Vaginal examination with a cervical examination can be used for fetal scalp stimulation-rubbing the baby's head to provoke an acceleration of the fetal heart rate. However, this does not usually provoke uterine hyperstimulation.