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NCT Number: NCT07312227

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.

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Key information

Conditions

Hypertensive Disorder of Pregnancy Congenital, Hereditary, and Neonatal Diseases and Abnormalities Female Urogenital Diseases and Pregnancy Complications Fetal Diseases Fetal Growth Retardation Growth Disorders Hypertension, Pulmonary Infections Intrauterine Growth Restriction Lung Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Pregnancy Complications Pulmonary Arterial Hypertension Respiratory Tract Diseases Toxemia Urogenital Diseases

Age range

18 year–45 year

Sex eligibility

Female

Study type

Observational

Primary location

Hospital De La Meujer, La Paz, Bolivia

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About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Primary outcomes

  1. Pulmonary artery pressures

    Time frame: Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks)

    Measurement will be performed by transthoracic echocardiography.

  2. Echographic estimate of fetal weight

    Time frame: Late pregnancy (35 ± 4 weeks gestation)

  3. Nitric oxide metabolites

    Time frame: Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks) for maternal samples, at delivery (neonatal samples)

    Measurement will be performed with a chemiluminescence assay.

  4. RV remodeling echocardiography parameters

    Time frame: Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks)

  5. Weight at birth

    Time frame: At delivery

Study contacts

Contact information is provided by the study sponsor or research team.

Andrea Bolchini, MD

CONTACT

[email protected]

617-216-5124

Lorenzo Berra, MD

CONTACT

[email protected]

617-726-3030

Sponsors and collaborators

Lead sponsor

Massachusetts General Hospital

Other

Registry information

Important dates

Study start
2026
Primary completion
2026
Study completion
2027
First posted
Dec 31, 2025
Registry last updated
May 26, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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