This is a single-center, prospective observational study in patients undergoing cesarean delivery under spinal or combined spinal-epidural anesthesia. It compares whether continuous noninvasive hemodynamic measurements from the lower extremity (toe) better predict neonatal outcomes than upper extremity (arm/finger) measurements during spinal-induced hypotension.

Participants receive standard spinal anesthesia and routine blood pressure management, with additional monitoring using the ClearSight™ system at both upper and lower extremities from before spinal anesthesia through delivery.

The primary outcome is a composite of neonatal outcomes (APGAR scores, need for respiratory support, cord gases, and NICU admission). Secondary outcomes include maternal side effects and comfort.

Overall, the study evaluates whether lower-extremity hemodynamic monitoring improves detection of clinically relevant hypotension and prediction of neonatal outcomes compared to traditional arm measurements.

Enrolled parturients undergoing elective cesarean delivery under spinal anesthesia will participate in this prospective, observational study following informed consent. Standard perioperative care will be maintained, including administration of spinal anesthesia (1.6 mL of 0.75% hyperbaric bupivacaine with fentanyl 10 mcg and morphine 100 mcg), crystalloid co-loading, and a prophylactic phenylephrine infusion. For study purposes, the ClearSight™ system will be applied noninvasively to both the upper and lower extremities, with a finger cuff placed on the ring finger of the arm opposite the intravenous line and a toe cuff placed on the left foot, while a standard oscillometric blood pressure cuff will be placed on the same arm. Continuous beat-by-beat blood pressure and flow measurements will be recorded from 3 minutes prior to spinal anesthesia placement until 3 minutes after neonatal delivery, alongside routine intermittent arm cuff measurements. Intraoperative maternal events and hemodynamic parameters will be documented, and neonatal outcome data-including Apgar scores, need for airway support, and NICU admission-will be extracted from the electronic medical record. No additional interventions beyond standard care will be performed, and all data collected will be used to compare the predictive performance of upper versus lower extremity hemodynamic measurements for neonatal outcomes.

Inclusion Criteria:

• Age ≥ 18 years old
• Singleton pregnancy
• Gestational age ≥ 37 weeks
• Women undergoing CD under SAB or Combined Spinal-Epidural (CSE) electively.
• Ability to consent in English and in Spanish language

Exclusion Criteria:

• CD under or converted to general anesthesia
• CD under epidural anesthesia or converted to epidural anesthesia
• Diabetes Mellitus (DM)/Gestational Diabetes Mellitus (GDM)
• Evidence of unstable cardiac disease other than HDP (including chronic hypertension, gestational hypertension, preeclampsia-eclampsia, and chronic hypertension with superimposed preeclampsia) judged by the investigator to have any impact on BP will make the subject unsuitable for participation in the study
• Documented fetal anomaly/ congenital malformations and genetic syndromes
• Intrauterine growth retardation
• Unable to consent in English/Spanish.
• Prisoners

The study includes adults, children, English- or Spanish-speaking individuals, and pregnant women (and their fetuses). It excludes adults with impaired decision-making capacity, nonviable neonates, neonates of uncertain viability, and prisoners. Eligible participants must be ≥18 years old, able to provide consent in English or Spanish, and have a singleton pregnancy at ≥37 weeks gestation. Exclusion criteria include documented fetal anomalies, congenital malformations, or genetic conditions; unstable cardiac disease (other than hypertensive disorders of pregnancy) that may affect blood pressure; and intrauterine growth restriction. Prisoners and other vulnerable populations are excluded.