This study is being done to determine the most effective dose of medicine to use to initially provide effective pain relief within the first 30 minutes of receiving an epidural for pain labor during labor. The study team will also study any side effects related to the epidural medication and patients' satisfaction with the quality of pain relief after receiving the epidural.

We aim to perform a prospective observational study in a single cohort of 50 patients receiving a dural-puncture epidural technique for labor analgesia. We will use a biased-coin up-down allocation methodology to quantify the volume of a combined epidural 0.1% ropivacaine and 2 mcg/ml fentanyl regimen that achieves effective analgesia in 90% of patients experiencing active labor who receive a dural-puncture epidural technique for labor analgesia.

Inclusion Criteria:

• Patients with singleton vertex pregnancies in active labor (latent or spontaneous labor or after induction of labor)
• Cervical dilatation between 2 and 7 cm
• Requesting neuraxial labor analgesia
• Age 18 or older

Exclusion Criteria:

• Significant obstetric disease (e.g., pre-eclampsia, major cardiac disease)
• Chronic pain or chronic opioid use
• BMI ≥ 50
• Multiple gestations
• Allergy or anaphylaxis to local anesthetic
• Fetal compromise or non-reassuring fetal trace
• Age under 18
• Inability to speak and understand English or Spanish

Pregnant birthing patients