With the high standards of obstetric and gynecology services today, pregnancy-related deaths are few and far between. It is worth recalling that for most of human history, pregnancy-related care was virtually nonexistent: no prenatal scans, no predelivery checkups, and no genetic testing. In the past, every pregnancy came with great inherent risks, and when problems such as a breech birth or postpartum hemorrhage occurred, midwives could only do so much. 

Today, pregnancy still comes with some risks, such as preeclampsia, but these dangers are usually detected before the due date, and physicians can take the necessary precautions to minimize the risk of a dangerous delivery. However, the situation remains complicated in the cases of women with pre-existing conditions such as pulmonary arterial hypertension (PAH). 

Low and Granton, in their editorial on the risks of pregnancy in a woman with PAH, shared their insights into this particular state of affairs. They start their study by stating a sobering fact: “PAH predominately affects women and is characterized by the progressive obliterative pulmonary vascular disease that, even in the face of medical therapies, continues to cause right heart failure and death for many.” Their verdict? “For those with PAH, pregnancy is particularly hazardous.” 


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A Risk Factor for Poorer Outcomes

Low and Granton described a study that suggests that parity in women with PAH is a risk factor for poorer outcomes. A study compared 156 pregnant women in China who developed PAH during their first pregnancy (n=108) and those who developed PAH during their second pregnancy (n=48).

They found that the group of women with their first pregnancy had more babies delivered at term (58% vs 38%), and fewer had low-birth-weight babies (24% vs 45%). In addition, a significantly lower number of patients in the first pregnancy cohort developed heart failure, compared to the second (6% vs 19%). The researchers also discovered that the cumulative maternal death rate in 48 months of follow-up was significantly lower in the first pregnancy group (3% vs 10%). 

When commenting on these findings, Low and Granton wrote, “Whether pregnancy is a trigger for pulmonary vascular remodeling and how it acts as a factor affecting disease progression, remain to be elucidated.”

A significant barrier to our knowledge of PAH-associated pregnancy is that clinical trials are hardly conducted on pregnant women, due to the potential risks to both mother and fetus. Thus, clinicians have to make decisions based on documented clinical outcomes, as opposed to original clinical research. 

Read more about PAH epidemiology 

Olsson and Channick, in their study on pregnancy in PAH, provided a similarly sobering assessment of the risks that pregnant patients face. “Despite advanced therapies, maternal mortality in women with PAH remains high in pregnancy and is especially high during the post-partum period,” they wrote. “The current European Society of Cardiology/European Respiratory Society guidelines recommend that women with PAH should not become pregnant” and that “early termination should be discussed.”

In this scenario, it is the health (and indeed, survival) of the mother that physicians are trying to prioritize. “Given that PAH often affects women of child-bearing age, it should be made clear to women at the time of their PAH diagnosis that pregnancy is not recommended due to the high maternal and fetal risks,” Olsson and Channick wrote. “Counseling should be offered to women and their families at the time of PAH diagnosis, together with an individual patient risk assessment, in a pulmonary hypertension center with experience in the management of pregnancy in PAH.”

Managing High-Risk Pregnancies 

So what can be done to support women who choose to go ahead with pregnancy? Olsson and Channick have a few excellent recommendations. For example, they recommended that anticoagulation medication be prescribed to reduce the risk of venous thromboembolic events in pregnant women.

In addition, “due to increased fluid retention and blood volume during pregnancy, it is particularly important to manage peripheral edema, a symptom of right heart failure in PAH,” they wrote. Diuretics may also be needed to treat right-sided heart failure in pregnant women with PAH, as well as to reduce fluid overload during delivery.  

Read more about PAH patient education 

Low and Granton wrote that echo-derived right ventricular evaluation for pregnant women with PAH can be of immense value. In addition, they recommended that a multidisciplinary team be involved in managing pregnant patients with PAH.

“The importance of an interprofessional team in treating PAH in pregnancy cannot be overemphasized, with the involvement of at least the PAH specialist, high-risk obstetrician, intensive care specialist, and obstetric anesthetist in joint decision making for improved outcomes,” they wrote.

If the patient decides to go ahead with pregnancy with full awareness of the risks involved, physicians must do everything they can to support the patient’s decision. Olsson and Channick recommended a scheduled cesarean section delivery as a means to avoid lengthy labor. They wrote that “women with PAH should ideally not go into labor naturally,” although practices differ across centers. 

Ultimately, physicians should do everything in their power to ensure that PAH in pregnant women is well-managed. To improve data-gathering concerning pregnancy in women with PAH, Low and Granton called for “international collaboration to gather PAH data in pregnancy systematically in prospective registries, to uncover data-driven decision making and future directions for research.” 

References

Low TT, Granton J. Pregnant with pulmonary arterial hypertension – can we handle the pressure? Int J Cardio. 2021;328:180-181. doi:10.1016/j.ijcard.2020.11.036

Olsson KM, Channick R. Pregnancy in pulmonary arterial hypertension. Eur Respir Rev. 2016;25(142):431-437. doi:10.1183/16000617.0079-2016.