Long-Term Risk of Cardiovascular Disease in Mothers and Their Children After Pregnancy Complications

Back in April, we introduced a new series in which we discuss medical problems during pregnancy that increase the risk of medical problems for the mother later in life. As part of the series, we recently explored the pregnancy complication preeclampsia, and how it appears to increase a mother’s risk of suffering a stroke later in life, yet earlier than old age, which is when it usually occurs. In the introduction to the series, we noted that, of mothers who die on account pregnancy complications, only approximately 31 percent die actually during pregnancy. A substantial fraction of deaths, illness, and disability occur much later, including many years later. Today we’ll look at cardiovascular disease (diseases of the blood vessels of the heart) and heart disease overall. Not only is the risk for this category of disease elevated in mothers decades after they suffer an adverse pregnancy condition or outcome, but recent research suggests that children of such mothers also have elevated risk for heart disease.

In medicine, the term adverse pregnancy outcomes (APOs) refer to major problems that can develop in a pregnant woman, or that the fetus can develop. Several APOs have been discussed here on The Pulse. Examples of APOs include hypertensive (high blood pressure) disorders of pregnancy. Within this category are gestational hypertension (high blood pressure that is present only during pregnancy), preeclampsia, eclampsia, HELLP syndrome, and chronic hypertension with superimposed preeclampsia). Other categories of APO include gestational diabetes, preterm birth, fetal growth restriction, and various things that can go wrong with the placenta. When it comes to APOs in the mother, we tend to focus on what such complications could mean for the health and development of the newborn and what they could mean for the short-term health for the mother, such as whether she will be in danger of losing her life during pregnancy, or just after childbirth. However, researchers also have been studying long-term effects of APOs.

High risk related to heart disease can occur at all ages but increases with older motherhood. In the case of certain APOs, notably preeclampsia and eclampsia, the higher risk falls on both mothers who are older and those who are very young (teenage pregnancy). Furthermore, pregnancy complications are much more likely to strike particularly women who are African American, Hispanic, and Asian. Nevertheless, of the mothers who die on account pregnancy complications, only around one third (31 percent) die during pregnancy itself. About another one third (36 percent) lose their lives at delivery, or within a week of delivering, but the remaining third (33 percent) from one week after delivery to much later.

In recent years, cardiology researchers have found that APOs can affect maternal heart health for much longer periods after childbirth. While cardiovascular disease, which can lead to heart attacks and heart failure notoriously strikes older people, it tends to strike earlier, such as in middle age, in mothers who have suffered APOs, such as preeclampsia, during their pregnancies. The mechanism relates to problems of the inner walls of arteries. This makes sense, because various APOs, including preeclampsia and HELLP syndrome are thought to involve problems with the blood vessels in the placenta, as well as in other areas throughout the body.

One of the worse consequences of cardiovascular disease is what doctors call acute coronary syndrome (ACS), which is commonly called a heart attack. ACS is subdivided into two broad categories: non-ST elevation-acute coronary syndrome (NSTE-ACS) and ST elevation myocardial infarction (STEMI). The first category, NSTE-ACS consists of two severity types – non-STEMI (NSTEMI) and unstable angina, which used to be two completely separate categories, but are grouped together now, because they exist along a spectrum of disease with much overlap between them. As for the STEMI category, this is the most severe type of ACS, the type that requires invasive treatment.

The term infarction refers to the death of tissue in a particular region, due to the blood supply being inadequate in supplying the affected region with oxygen and other consumables. In the heart, most of the needed blood flow is to supply what’s called the myocardium. Thickest of the layers of tissue that form the heart, the myocardium consists of muscle cells. ACS occurs because of problems with the wall of one or more arteries supplying the myocardium. This results in a plaque on the inner layer of the artery, which can start to obstruct blood flow and cause a blood clot which further obstructs blood flow. The increasing amount of obstruction, from slight to completely across the artery, correlates with the severity of ACS and with the amount of damage to the heart muscle supplied by the affected artery.

A diagnosis of NSTE-ACS generally means that the progression of the condition can be stopped by giving you various medications, as long as the condition remains limited to NSTE-ACS and does not worsen into STEMI. In contrast, STEMI requires immediate intervention with reperfusion (reestablish circulation of blood) of the affected parts of the heart. This means either removing the obstruction from the blocked artery or arteries, or detouring blood around the obstruction. The first option, opening the blocked artery or arteries can be achieved through what is called percutaneous coronary intervention (PCI). In this procedure, a stent (a tube that holds the artery open from the inside, providing a tunnel for the blood) is placed in the affected region of the affected artery/arteries. If the arteries cannot be stented, if too many arteries are obstructed, or if a main coronary artery is obstructed, then the patient would need a surgical procedure called coronary artery bypass grafting (CABG, pronounced like the vegetable cabbage). In CABG, surgeons remove parts of blood vessels from other parts of the patient’s body and transplant them into the heart in a way that bypasses the blood around the obstructed portion of each affected artery and delivers the blood back into the affected artery downstream from the obstruction.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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