A Prospective Longitudinal Observational Cohort Study of Pregnant Women Residing at High Altitude in Bolivia

In this study, the investigators will follow two small cohorts of pregnant women: a cohort of healthy women with uncomplicated pregnancies residing at high altitude, a control group of healthy women with uncomplicated pregnancies residing at sea level, to characterize differences in cardiopulmonary adaptation and nitric oxide (NO) pathway expression at elevations >3,500 m throughout pregnancy and into the postpartum period. The investigators aim to investigate right-sided cardiac impairment induced by chronic hypobaric hypoxemia, its effects on fetal growth, and the potential contribution of cardiovascular nitric oxide depletion to obstetric complications.

Study Overview

• Status: Recruiting
• Conditions: Pulmonary Arterial Hypertension; Intrauterine Growth Restriction; Hypertensive Disorder of Pregnancy

Detailed Description

To investigate cardiac impairment, the investigators will perform transthoracic echocardiography in all enrolled pregnant women and infants, with a focus on right-sided cardiac anatomy and function, including pulmonary artery pressures, right ventricular thickness, right ventricular systolic performance, and indices of pulmonary vascular load.

To investigate the effects of hypobaric hypoxia on fetal growth, the investigators will measure intrauterine and post-delivery growth parameters, assess placental weight and histologic features, and correlate these findings with maternal oxygenation status and altitude exposure.

To assess nitric oxide production and consumption, the investigators will quantify nitric oxide-related metabolites (NO metabolomics) in maternal blood, umbilical cord blood, and placental tissue in both cohorts, and correlate these biomarkers with pulmonary arterial pressures, and right ventricular function. The investigators will also assess flow-mediated dilation in the high altitude cohort and relate these measures of endothelial function to pulmonary vascular and obstetric outcomes.

• Study Type: Observational
• Enrollment (Estimated): 27

Contacts and Locations

• Study Contact: Name: Lorenzo Berra, MD; Phone Number: 617-726-3030; Email: lberra@mgh.harvard.edu
• Study Contact Backup: Name: Andrea Bolchini, MD; Phone Number: 617-216-5124; Email: abolchini@mgh.harvard.edu

Study Locations

• Bolivia
  • La Paz, Bolivia
    • Completed
    • Hospital De La Meujer
• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Recruiting
      • Massachusetts General Hospital
      • Contact: Lorenzo Berra, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The cohort of healthy pregnant women residing at high altitude will selected from pregnant women who have lived at an altitude greater than 3500 meters throughout pregnancy and at delivery. The control group will be pregnant women who have lived at sea level throughout pregnancy and at delivery.

Description

Inclusion Criteria:

• women delivering at participating hospitals at more than 3500 meters or women delivering at participating hospitals at sea level
• signed informed consent

Exclusion Criteria:

• preexisting cardiopulmonary pathologies (CHD, COPD, CKD, NYHA > III)

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Healthy pregnant women residing at high altitude; Women with uncomplicated pregnancy.
Healthy pregnant women residing at sea level; Women with uncomplicated pregnancy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pulmonary artery pressures	Measurement will be performed by transthoracic echocardiography.	Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks)
Echographic estimate of fetal weight		Late pregnancy (35 ± 4 weeks gestation)
Nitric oxide metabolites	Measurement will be performed with a chemiluminescence assay.	Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks) for maternal samples, at delivery (neonatal samples)
RV remodeling echocardiography parameters		Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks)
Weight at birth		At delivery

Collaborators and Investigators

• Sponsor: Massachusetts General Hospital
• Investigators: Principal Investigator: Lorenzo Berra, MD, Massachusetts General Hospital

Study record dates

Study Major Dates

• Study Start (Actual): February 11, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: December 3, 2025
• First Submitted That Met QC Criteria: December 16, 2025
• First Posted (Actual): December 31, 2025

Study Record Updates

• Last Update Posted (Actual): May 26, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Pathologic Processes; Female Urogenital Diseases and Pregnancy Complications; Pregnancy Complications; Infections; Respiratory Tract Diseases; Lung Diseases; Fetal Diseases; Growth Disorders; Hypertension, Pulmonary; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Pathological Conditions, Signs and Symptoms; Pulmonary Arterial Hypertension; Fetal Growth Retardation; Toxemia
• Other Study ID Numbers: PregHigh

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No