Sex, Gender Have Major Implications on Cardiovascular Health in Children, Young Adults

Differences between the sexes and genders in cardiopulmonary diseases were the highlight of a session at the American Thoracic Society 2026 International Conference, taking place in Orlando, Florida, from May 17-20, 2026. The session focused primarily on how pregnancy can affect women living with pulmonary hypertension (PH), how the cardiovascular outcomes in pre-term infants are different based on sex, and how adolescence can bring an increased incidence of PH in women.

PH With Pregnancy Can Prove Dangerous for Women

Anna Hemnes, MD, ATSF, chair of the Department of Medicine for Vanderbilt Health, opened the session by focusing on how pregnancy can affect women with PH. The physiology of a normal pregnancy, she said, can include mechanical changes like the chest wall widening to accommodate the growth of the uterus. There is also a rise in progesterone, and estrogen rises throughout the pregnancy, which can have an effect on the cardiopulmonary system. Cardiac output is also at an increased rate between 15 and 40 weeks during the pregnancy, peaking at a little more than 40% in change from baseline.

“That’s oftentimes where, if problems are going to occur because of increased blood flow, that’s when that happens,” she said. “…It’s a little bit like exercise all the time when you’re pregnant by mid-pregnancy.”

The increase in cardiac output and blood volume is accommodated through dilation of the left ventricle, which can cause an increase in left ventricular ejection fraction. Hemnes reiterated that identifying what triggers the progression from this enlargement and structural changes in women—and how the heart subsequently returns to normal—could be key in treating right heart failure better.

However, when it comes to pregnancy, these physiological changes can be a big detriment to a woman’s health. “By the time [a patient with PH] manifests in our clinic, they have maximally dilated and recruited their blood vessels. They’ve already done the things that pregnancy has done, and yet the pressure has risen accordingly…as a result, pressure rises very early in the context of pregnancy,” said Hemnes.

Pregnancy in patients with PH can ultimately affect their hearts in the long term and may lead to right heart failure during delivery. Hemnes recommends counselling women to avoid pregnancy if they have risk of PH, but some studies have found that patients with low-risk PH may be able to carry out the pregnancy through shared decision-making.

“Pulmonary hypertension is a unique challenge in pregnancy with evolving recommendations based on risk, patient risk tolerance, and multidisciplinary care,” she concluded.

How Sex Plays a Role in Cardiopulmonary Development

Krithika Lingappan, MD, PhD, MS, an attending neonatologist with the Division of Neonatology at Children’s Hospital of Philadelphia, continued the session with a discussion on the infants who may be affected by cardiopulmonary development, based on their sex.

Lingappan pointed out that more preterm infants are living to adulthood and thereby expanding the population of those who have a history of prematurity. These patients often have other chronic health issues, including structural cardiopulmonary limitations, that can go unnoticed in clinical settings if patients do not bring them up or clinicians do not ask.

In a study using data from the Vermont Oxford Network Center that included 205,750 infants born between 22 and 29 weeks,¹ researchers found that the incidence of chronic lung disease was higher in preterm neonates who were born male compared with those born female. “Us neonatologists, we accept this as a clinical truth…but I think we are still a little behind in understanding what the biological underpinnings of this difference might be,” said Lingappan.

She also noted that if this population were exposed to a second hit, they could have a rapid decline in lung function, which can make them susceptible to adult-onset lung diseases. Males born preterm also start to see separation in lung function from their female counterparts as early as 25 years of age. “In [women], even though they leave the [natal intensive care unit] with a lower lung reserve, their lung function remains constant throughout at least the second decade of life,” she explained.

Infants born before 28 weeks also had a significantly higher risk of cardiovascular disease compared with those born at 37 weeks or later,² with those born between 28 and 36 weeks also having an increased risk of cardiovascular disease, although to a lesser degree than those born before 28 weeks.

“Prematurity is an important cardiopulmonary risk marker, and we need to do more education so that the parents and the patients remember that this is a risk factor that they carry through their lifespan. But we as clinicians, both pediatricians and adult pulmonologists and cardiologists, remember to ask the question of your patient of whether they were born preterm,” concluded Lingappan.

PH Manifest Differently Through Adolescence

Megan Griffiths, MD, a pediatric cardiologist at the University of Texas Southwestern Medical center, spoke about how PH can change through adolescence due to the changes that come with puberty. Adolescence, she said, matters because it is a period of rapid and massive growth in young children, which demands more cardiopulmonary output during the time. For patients who already have PH, they are at an increased risk.

“If we look at numbers before adolescence, it’s about a 1:1 male to female ratio, whereas post adolescence, idiopathic and paradigm PH has been 4:1 female to male,” she said.

Estrogen is a cause of this, as estrogen promotes the development of PH. However, once PH is established, estrogen is protective, and women will survive for longer than men if both have PH. When it comes to adolescents, women who are developing these symptoms may not report them as they become young adults, as they could minimize symptoms or not know how to advocate for themselves. Adolescents also have severe hemodynamics but can still perform well on the 6-minute walking test despite that.

Overall, Griffiths concluded that adolescents are uniquely vulnerable to PH. “We really need to start coming up with some age-appropriate ways to assess them that help for their resilience and their developmental stress.”

References

1. Boghossian NS, Geraci M, Edwards EM, Horbar JD. Sex differences in mortality and morbidity of infants born at less than 30 weeks’ gestation. Pediatrics. 2018;142(6):e20182352. doi:10.1542/peds.2018-2352
2. Carr H, Cnattingius S, Granath F, Ludvigsson JF, Bonamy AKE. Preterm birth and risk of heart failure up to early adulthood. J Am Coll Cardiol. 2017;69(21):2634-2642. doi:10.1016/j.jacc.2017.03.572