An observational study in Hypertensive Disorder of Pregnancy, Pulmonary Arterial Hypertension and Intrauterine Growth Restriction, sponsored by Massachusetts General Hospital. Recruiting at 2 sites in 2 countries. Open to female participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-26.
Sponsored by Massachusetts General Hospital · Observational
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.
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.
699 studies on the registry are indexed under Pulmonary Arterial Hypertension; 140 are open to participants now.
This study's planned enrollment of 27 is below the median of 104 across 181 observational studies indexed under Pulmonary Arterial Hypertension.
Browse Pulmonary Arterial Hypertension studies →Massachusetts General Hospital is the lead sponsor of 2,586 studies on the registry; 447 are open to participants now.
Of its 222 completed or terminated interventional studies of FDA-regulated products, 168 (76%) have results posted.
Counted across the registry records on this site, refreshed daily.
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.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Women with uncomplicated pregnancy.
Women with uncomplicated pregnancy.
Pulmonary artery pressures
Measurement will be performed by transthoracic echocardiography.
Time frame: Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks)
Echographic estimate of fetal weight
Time frame: Late pregnancy (35 ± 4 weeks gestation)
Nitric oxide metabolites
Measurement will be performed with a chemiluminescence assay.
Time frame: Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks) for maternal samples, at delivery (neonatal samples)
RV remodeling echocardiography parameters
Time frame: Late pregnancy (35 ± 4 weeks gestation) and postpartum (6 ± 0.3 weeks)
Weight at birth
Time frame: At delivery
Not enrolling at this site.
Started Feb 2026 (actual). Primary completion is estimated for Dec 2026, 10 months after the start.
Of 64 non-industry observational studies under Pulmonary Arterial Hypertension, half reached primary completion within 60 months of starting (the median), counting those still running; a quarter within 31. This study's planned 10 months is below that.
Counting every sponsor, half of 85 studies reached it within 58 months; a quarter within 30 and three quarters within 93.
How these figures are worked out, and which studies are left out of them.
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Pulmonary Arterial Hypertension →
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