Due to change on standard of care, higher doses of fentanyl requirements are rare.

This study is being done to investigate if there is more effective pain relief during the latter stages of labor and delivery when epidural fentanyl 100mcg is administered compared to epidural fentanyl 20mcg.

The objective is to evaluate if high-dose epidural fentanyl (100 micrograms) is more effective at providing pain relief during the late first stage (>8 cm cervical dilation) and second stage of labor until the time of delivery compared to low-dose epidural fentanyl (20 micrograms). In this study, anesthetic care will be provided to a subject by an experienced anesthesia provider according to standard hospital care. If the subject has adequate pain relief from the continuous epidural infusion, then a study investigator will record the verbal pain score and document any other side effects at hourly intervals beginning at >8cm cervical dilation, but no additional epidural medications will be administered. If pain relief becomes inadequate during the late first or second stage of labor (>8cm cervical dilation) and a manual epidural bolus is required, then the subject will be randomly assigned to one of two groups (like flipping a coin): one group will receive lower dose epidural fentanyl (20 micrograms) combined with local anesthetic; and one group will receive higher-dose epidural fentanyl (100micrograms) combined with the same amount of local anesthetic. Both doses are used frequently on labor and delivery and are considered to be safe based on available evidence. If there is not sufficient pain relief from the epidural medication given, then an experienced anesthesia provider will assess if another epidural dose may be effective and this additional epidural medication will be given at the discretion of the anesthesia provider. An experienced anesthesia provider will be available at all times during the study to assess pain and provide epidural medications. All patients participating in the study will have their pain scores assessed every hour as soon as the cervical dilation is noted to be >8cm; at the time of randomization; and at 10, 20, 30 and 60 minutes after the epidural dose is administered. The presence of any side-effects such as itching, shivering, nausea, vomiting, low blood pressure, slow respiratory rate or lower extremity muscle weakness will also be collected at hourly intervals as soon as the cervical dilation is noted to be >8cm. Subject satisfaction (1-100 rating scale) with anesthetic care provided will be assessed on postpartum day # 1 during routine follow-up visit.

Inclusion Criteria:

1. Nulliparous women
2. Spontaneous labor
3. A single vertex presentation fetus at term (38-42 weeks)
4. Effective labor epidural analgesia with continuous epidural infusion established
5. Provide written consent to participate in the study.

Exclusion Criteria:

1. Multigravida women
2. Multigestation pregnancies
3. Patients being treated/managed for chronic pain
4. Allergies or significant adverse reactions to local anesthetic or opioid medications
5. Inadequate or unsatisfactory labor epidural analgesia
6. Patients with history of spine abnormalities or spine surgery
7. Non-English speaking
8. Prisoners
9. Age less than 18 years old

Must be pregnant woman to considered for study.

No plan to share IPD.

The subject and the research personnel will be blinded to the arm to which they are randomized. Only the clinician assessing the patient and administering epidural doses will be not be blinded to the study group.