The Association Between Fluid Administration, Oxytocin Administration, and Fetal Heart Rate Changes

Fetal heart rate patterns are an important parameter in the diagnosis of non-reassuring fetal status. Combined-spinal epidural analgesia is a method of initiating labor analgesia used by approximately 90% of the parturients at Prentice Women's Hospital. Optimizing the variables which could affect fetal heart rate patterns at the time of initiation of analgesia, such as fluid administration and oxytocin management, could help us provide better care for our patients and their fetuses. Hypotheses: The combination of fluid administration and lower doses of oxytocin administration will have fewer adverse fetal heart rate changes in the first 60 minutes following initiation of labor analgesia.

After obtaining informed, written consent, candidates were randomized to one of four groups at the time of request for labor analgesia. All subjects received a maintenance infusion of Lactated Ringers(LR). For candidates in Groups A or B, an intravenous bolus of 1000 mL of LR was initiated. Candidates in Groups C and D did not receive any additional fluid. If randomized to group A or C, the oxytocin management was continued as per the normal active management of labor protocal (AMOL). If randomized to groups B or D, the dose of oxytocin that was being administered was halved and not increased until 60 minutes after the initiation of epidural analgesia. Fetal heart rate monitoring and frequency of uterine contractions were recorded by external tocodynamometry.

An intravenous bolus of 1000 mL Lactated Ringers initiated when the patient is positioned for epidural placement. Oxytocin management continued as per protocol.

An intravenous bolus of 1000 mL Lactated Ringers. The dose of oxytocin being administered at time of epidural placement will be halved and not increased for 60 minutes until after placement.

The maintenance infusion of 125 mL/hr of Lactated Ringers will be given with no additional fluid bolus. Oxytocin management continued per protocol.

The maintenance infusion of 125 mL/hr of Lactated Ringers will be given with no additional fluid bolus. The dose of oxytocin being administered at time of epidural placement was halved and not increased for 60 minutes until after placement.

An intravenous bolus of 1000 mL Lactated Ringers initiated when the patient was positioned for epidural placement. Oxytocin management continued as per protocol.

Group B Intravenous bolus bolus 1000 ml lactated ringers solution oxytocin decrease to 1/2 current rate

An intravenous bolus of 1000 mL Lactated Ringers. The dose of oxytocin being administered at time of epidural placement will be halved and not increased for 60 minutes until after placement.

The maintenance infusion of 125 mL/hr of Lactated Ringers will be given with no additional fluid bolus. Oxytocin management continued per protocol.

The maintenance infusion of 125 mL/hr of Lactated Ringers was given with no additional fluid bolus. The dose of oxytocin being administered at time of epidural placement will be halved and not increased for 60 minutes until after placement.

Number of Participants With Non-reassuring Fetal Heart Rate Tracings During the First 30 Minutes After the Placement of Epidural Analgesia

The number of participants who experience non-reassuring fetal heart rate tracings obtained via electronic recording during the first 30 minutes after the placement of epidural analgesia

Inclusion Criteria: Age 18-60 Healthy nulliparous or multiparous women Term (>36 week gestation) Singleton pregnancy Spontaneous labor or with spontaneous rupture of membranes Receive oxytocin Request neuraxial analgesia Exclusion Criteria: Under 18 years of age Presence of any systemic disease (e.g., diabetes mellitus, hypertension, preeclampsia) Use of chronic analgesic medications Prior administration of systemic opioid labor analgesia Non-vertex presentation Induction of labor Contraindication to neuraxial analgesia.

Mardirosoff C, Dumont L, Boulvain M, Tramer MR. Fetal bradycardia due to intrathecal opioids for labour analgesia: a systematic review. BJOG. 2002 Mar;109(3):274-81. doi: 10.1111/j.1471-0528.2002.01380.x.

Clarke VT, Smiley RM, Finster M. Uterine hyperactivity after intrathecal injection of fentanyl for analgesia during labor: a cause of fetal bradycardia? Anesthesiology. 1994 Oct;81(4):1083. doi: 10.1097/00000542-199410000-00041. No abstract available.

Lopez-Zeno JA, Peaceman AM, Adashek JA, Socol ML. A controlled trial of a program for the active management of labor. N Engl J Med. 1992 Feb 13;326(7):450-4. doi: 10.1056/NEJM199202133260705.