A pregnant patient, gravida 2, para 1, at 41 weeks and 1 day gestation is admitted to the … — USMLE Step 2 CK

A pregnant patient, gravida $2$ , para $1$ , at $41$ weeks and $1$ day gestation is admitted to the labor unit for a scheduled induction of labor due to a post-term pregnancy. She is receiving a continuous intravenous infusion of a synthetic uterotonic agent to stimulate uterine activity. Her medical history is unremarkable, and her previous delivery was an uncomplicated vaginal birth.

Current maternal vital signs reveal a blood pressure of $115/75\text{ mmHg}$ , heart rate of $86\text{/min}$ , and temperature of $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ). Uterine contractions are occurring every $3$ to $4\text{ minutes}$ and palpate as strong. A sterile vaginal examination reveals the cervix is $5\text{ cm}$ dilated, $90\%$ effaced, and at $-1$ station.

Continuous electronic fetal monitoring displays a baseline heart rate of $140\text{/min}$ with moderate variability. Over the past $25\text{ minutes}$ , the tracing demonstrates recurrent, symmetric, gradual decreases in the fetal heart rate that begin after the peak of each uterine contraction and slowly return to the baseline after the contraction ends. These decelerations are occurring with approximately $75\%$ of the contractions. The patient is repositioned to her left side and provided with supplemental oxygen, but the fetal heart monitoring pattern remains unchanged.

Which of the following is the most appropriate next step in the management of this patient?

Halt the continuous synthetic uterotonic infusionCevap
B
Initiate a transcervical intrauterine fluid infusion
C
Administer subcutaneous terbutaline
D
Proceed with an urgent operative abdominal delivery
E
Perform fetal scalp stimulation

Cevap

Halt the continuous synthetic uterotonic infusion.

The patient's electronic fetal monitor demonstrates recurrent late decelerations, which are characterized by symmetric, gradual decreases in the fetal heart rate that nadir after the peak of the uterine contraction. These decelerations indicate uteroplacental insufficiency and constitute a Category II tracing when accompanied by moderate variability. Management requires immediate, stepwise intrauterine resuscitation to prevent fetal acidemia. Standard resuscitative measures include maternal repositioning (to relieve inferior vena cava compression), intravenous fluid boluses (to correct potential hypotension), administration of supplemental oxygen, and discontinuation of any uterotonic agents (to decrease uterine metabolic demand and improve placental blood flow). Because maternal repositioning and supplemental oxygen have already been attempted without resolution of the decelerations, the most appropriate next step is to halt the continuous synthetic uterotonic infusion.

Adım Adım Çözüm

Analyze the electronic fetal monitoring tracing described in the vignette.

The tracing shows recurrent, symmetric, gradual decreases starting after the peak of contractions, which defines recurrent late decelerations.

Accurate identification of the deceleration type is required to determine the underlying pathophysiology (uteroplacental insufficiency).

Classify the fetal heart rate tracing and determine the need for intervention.

The tracing is Category II (moderate variability with recurrent late decelerations), necessitating prompt intrauterine resuscitation.

Recurrent late decelerations can lead to fetal acidemia if uteroplacental blood flow is not restored.

Evaluate the resuscitative steps already taken.

Maternal repositioning (left lateral) and supplemental oxygen have already been administered without improvement.

Intrauterine resuscitation is a step-wise algorithm; recognizing completed steps dictates the next appropriate action.

Select the next appropriate resuscitative intervention based on the ongoing clinical scenario.

The continuous synthetic uterotonic infusion must be stopped.

Halting uterotonic stimulation decreases uterine metabolic demand and improves placental perfusion, addressing the uteroplacental insufficiency.

Anahtar Kavram

Intrapartum management of Category II fetal heart rate tracings with recurrent late decelerations

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