Scientists find new way to predict complications after childbirth in PAH
Elevated levels of heart-related protein can ID pregnant women at high risk
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Testing a pregnant woman’s levels of a protein linked to changes in the heart’s size and shape may help identify expectant mothers with pulmonary arterial hypertension (PAH) who are at high risk of serious complications after childbirth, a new study in China shows.
The researchers found that levels of the protein secreted phosphoprotein 1 (SPP1), which is involved in cell growth and heart changes, are “significantly elevated” in pregnant PAH patients — and that women who experienced “postpartum adverse events,” or complications after childbirth, had “higher SPP1 concentrations.”
As such, “SPP1 serves as an effective molecular biomarker for predicting postpartum risk in pregnant women with PAH,” the team wrote.
Additionally, the scientists determined that “combining SPP1 with clinical indicators … further improves prediction of adverse outcomes” for pregnant women with PAH, a type of pulmonary hypertension marked by a narrowing of the blood vessels that transport blood through the lungs.
According to the team, these findings demonstrate that determining SSP1 levels and using them alongside common clinical parameters can be an effective tool for assessing risk for PAH patients following childbirth.
Their study, “SPP1 improves early risk assessment of postpartum adverse events in pulmonary arterial hypertension complicated with pregnancy,” was published in the European Journal of Obstetrics & Gynecology and Reproductive Biology.
In PAH, narrowing of the pulmonary arteries that carry blood through the lungs creates too much pressure in those blood vessels, making the right side of the heart work harder to pump blood. This causes severe shortness of breath and can lead to fatigue, weakness, chest pain, dizziness, and fainting among patients.
Weeks after childbirth are ‘critical period’ for complications
The condition is more common in women, and pregnancy is contraindicated, or not recommended, in the PAH patient population. That’s because hormonal and anatomical changes that occur during pregnancy might be particularly troublesome for women with PAH.
Importantly, the risk of heart failure and other adverse events for pregnant PAH patients becomes greater during childbirth.
“However, increasing clinical evidence indicates that the high-risk period for patients with PAH is not limited to the time of delivery; the early postpartum stage — particularly from one week to 42 days after childbirth — also represents a critical period for the occurrence of severe adverse events,” the team wrote.
Having reliable biomarkers would be especially valuable to estimate risk, the investigators added, noting a particular need for markers related to scarring, or fibrosis.
Here, the team sought to determine if levels of SPP1 could help identify women at higher risk of serious complications after giving birth. To that end, the researchers analyzed several datasets comparing gene activity between PAH patients and healthy individuals.
The results showed that activity, or expression, of the SPP1 gene is significantly elevated in people with PAH.
The researchers then explored the clinical significance of the SPP1 protein by analyzing clinical data from 61 pregnant women with PAH and 20 healthy pregnant women, who served as controls. All were followed at a hospital in Beijing between 2021 and 2024. The PAH group had significantly higher levels of SPP1 than the controls, the data showed.
Protein test showed good ability to predict adverse events
Among the new mothers with PAH, about one third — 21 women — experienced adverse events for up to 42 days after childbirth. Such events primarily involved bleeding, progressive increase of pulmonary arterial pressure, heart failure, worsening heart function, and PAH crisis.
Those who experienced adverse events were more likely to have more severe heart failure, according to the New York Heart Association (NYHA) Functional Classification, and to have higher levels of heart damage markers, including B-type natriuretic peptide (BNP). SPP1 levels were also higher in women with complications after childbirth (63.56 vs. 39.62 nanograms/mL).
Based on systolic pulmonary artery pressure (SPAP), which measures the pressure in the lung arteries as the heart’s right ventricle pumps blood, 23 women had mild PAH, 13 had moderate disease, and 25 had severe PAH. Women with severe PAH showed significantly higher SPP1 levels than those with mild disease, according to the team.
The scientists then determined whether SPP1 could help gauge the risk of complications after childbirth using a statistical measure called area under the curve (AUC), where scores range from zero to one; the higher the AUC value, the better the ability to identify women at greater risk.
SPP1 alone showed good predictive ability for postpartum complications, with an AUC of 0.743. But adding it to a model that also used BNP, NYHA functional class, and systolic pulmonary artery pressure, increased AUC from 0.698 to 0.761.
According to the team, these findings show that SPP1 is effective as a molecular biomarker that can predict postpartum risk in pregnant women with PAH. Further, combining this measure with clinical parameters improved the predictive value of SPP1, the researchers concluded.
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