Pregnancy more likely to be favorable if mother’s PH is mild

Risk of complications rises with moderate-to-severe disease, study says

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Pregnant women with mild pulmonary hypertension (PH) show a significantly lower risk of maternal and fetal complications than those with moderate-to-severe PH, according to a study from China.

“For patients with mild pulmonary hypertension and good cardiac function, continued pregnancy or even delivery should be considered under multidisciplinary monitoring,” its researchers wrote.

Con­tinuous disease monitoring and control throughout the preg­nancy, “multidisciplinary, individualized treatment,” and planning for a preterm birth also help to further “improve maternal and fetal outcomes,” they added.

The study, “Pregnancy feasibility in women with mild pulmonary arterial hypertension: a systematic review and meta-analysis,” was published in the journal BMC Pregnancy & Childbirth.

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European guidelines advise against pregnancy with pulmonary hypertension

PH, a chronic and progressive disease, is characterized by increased blood pressure in the vessels that supply the lungs, risking heart failure. The disease also is known to put patients at a risk of pregnancy complications, and recent European Society of Cardiology guidelines advise against pregnancy for women with PH.

Despite advances in disease treatment and pregnancy management, questions remain as to whether women with mild PH can carry a child to term or have a vaginal delivery.

Researchers at Tongji Medical College in Wuhan conducted a systematic review and meta-analysis to compare maternal and fetal outcomes between women with mild PH and those with moderate-to-severe disease. A meta-analysis is an assessment that pools the results of several studies.

A total of 32 studies, published between January 1990 and April 2023 and reporting outcomes involving 2,520 women (mostly Chinese, ages ranging from 21 to 39), were used for the meta-analysis.

Maternal outcomes included mortality, the incidence (new cases) of cardiac complications, and intensive care unit (ICU) admission.

Fifteen studies covering 1,204 women assessed maternal mortality. Findings showed lower rates in women with mild and moder­ate PH, a mean of 0.15%, compared with those having severe disease, a mean of 9%. Women with mild PH had significantly lower rates than those with moderate-to-severe PH.

In a subgroup analysis looking at mortality rates before and after 2010, a significant drop was seen in the mild PH group: from a mean rate of 2.13% prior to 2010, to a rate of 0.08% after that year.

In contrast, no significant difference in maternal mortality was observed in women with moderate-to-severe PH before 2010 (mean rate, 9.45%) or after that year (mean rate, 9.28%).

Four studies assessed cardiac complications while four others reported ICU admission. Cardiac complications in pregnant women in the mild PH group were significantly lower (mean of 13%) than in women with moderate-to-severe PH (mean of 41%). Similarly, ICU admissions were a mean of 18% in mild PH patients and 55% in those with more advanced disease.

Careful and multidisciplinary monitoring of pregnancy seen as essential

More positive outcomes for newborns also were reported among women with milder PH relative to those with moderate-to-severe disease. Specifically, researchers found a significantly lower incidence of preterm birth in the mild PH group, 20% versus 43%; a lower rate of a smaller size for gestational age (6% mild PH vs. 40% more advanced PH); and a lower rate of low birth weight infants (18% vs. 34%), newborns with asphyxia or insufficient oxygen (7% vs. 17%), and neonatal mortality (1% vs. 6%). Gestational age refers to how far along in weeks a pregnancy has advanced since the mother’s last menstrual period.

The rate of cesarean section births was similar between the groups (80% vs. 79%), while rates of vaginal delivery were significantly higher in the mild PH group than in women with moderate-to-severe PH (16% vs. 7%).

Researchers also assessed the proportion of women with functional class III and IV PH during pregnancy, as defined by the New York Heart Association (NYHA). Class III is characterized by marked limitations in activity due to symptoms, and class IV denotes severe limitations, with symptoms present even at rest.

Fewer woman in the mild PH group were identified as having NYHA class III and IV PH relative to those with moderate-to-severe PH, a mean of 12% versus 55%.

Findings show “that pregnancies with mild pulmonary hypertension had significantly better maternal and fetal outcomes than those with moderate to severe pulmonary hypertension,” the investigators concluded.

The significantly higher likelihood of complications with more advanced disease, however, makes it “necessary to evaluate pregnancy risk and terminate it on time,” they added.

Among the study’s limitations were the observational nature of the included studies, with limited methodological quality; the considerable variability among some reported results; and the fact that most studies analyzed were in Chinese patients, so its overall conclusions may not be generalizable to the global PH population.

A Conversation With Rare Disease Advocates