What is coronary heart disease?
Also known as coronary artery disease (CAD), coronary heart disease (CHD) is a condition in which one or more arteries supplying the myocardium (the muscular layer of the heart) is unable to deliver enough blood and oxygen. This can happen due to an artery gradually becoming blocked due to atherosclerosis (the formation of plaques in the lining of the artery) resulting in the artery narrowing and the wall of the artery hardening; such changes typically have begun long before pregnancy, but changes in cardiovascular physiology associated with pregnancy can make it worse, such that previously symptomless atherosclerosis now becomes symptomatic, or less severe CHD now becomes worse. CHD can also develop during pregnancy, resulting from whats called spontaneous coronary artery dissection (a major artery supplying the heart tears within a short period of time), which often can be followed by atherosclerosis. In either case, a pregnant woman can develop a serious heart condition, ranging in severity from an inability of the heart to support normal physical activity such as walking up a flight of stairs, to a myocardial infarction (MI), a heart attack resulting from a portion of the heart muscle failing due to an inadequate oxygen supply.
How common is coronary heart disease in pregnancy?
Cardiovascular disease, which includes coronary heart disease, is rare in women of reproductive age, complicating about 0.4 percent to 4 percent of pregnancies. Despite its rarity among women of childbearing age, CHD is the leading cause of maternal mortality (pregnancy deaths).
How is coronary heart disease diagnosed during pregnancy?
Coronary heart disease diagnosis begins with your medical history, particularly your reporting of symptoms that could indicate presence of coronary conditions, such as dyspnea (difficulty breathing or shortness of breath), chest pain or feeling of heaviness on the chest, pain in other locations such as shoulder, arm, or neck, fatigue when you try to increase your activity (such as walking fast or climbing stairs), and palpitations or feelings that your heart has skipped a beat, or has made extra beats. The physical examination also can provide important hints of heart trouble. Your doctor will acquire more information from blood tests, and procedures such as electrocardiography (ECG) and echocardiography. In the course of evaluating you, your doctor may refer you to a specialist, such as a cardiologist or a specialist in high-risk pregnancies. In addition to determining whether you have a heart problem, doctors will evaluate various physiological values of your heart, such as the ejection fraction (what fraction of blood that enters a heart chamber is pumped out in each beat) and the stroke volume (the actual amount of blood that is pumped with each beat). These values normally change during pregnancy to meet the needs of supporting the developing baby, and so your heart function can worsen if you have an underlying problem. In evaluating you, doctors will rate your functional capability according to whats called the New York Heart Association (NYHA) Functional Classification (NYHA), which defines four classes:
- Class I: There is heart disease, but no symptoms that would limit your normal activity.
- Class II: There are mild symptoms, such as dyspnea or angina (chest pain that comes and goes)
- Class III: You are comfortable only when resting. Activity is limited, for instance, you can walk for only short distances
- Class IV: You feel symptoms even when resting and thus activity is extremely limited and you must remain in bed.
Risk during pregnancy from cardiovascular disease also rated in a classification system by the World Health Organization (WHO).
Does coronary heart disease cause problems during pregnancy?
Most cases of CHD in pregnant women put the woman into an NYHA Class I or Class II category, which generally means that the risk of problems is not elevated significantly. Along with numerous other cardiovascular conditions, CHD can be severe enough for you to be designated as Class III or IV, in which case carrying a pregnancy puts you at risk of life-threatening events.
Does coronary heart disease during pregnancy cause problems for the baby?
If your CHD is severe enough to put your health at risk while you are pregnant (Class III or IV), this puts the baby at risk for a range of problems, from distress and poor growth due to reduced blood circulation into the placenta to loss of the baby.
What to consider about taking medications when you are pregnant:
- The risks to yourself and your baby if you do not treat the coronary heart disease
- The risks and benefits of each medication you use when you are pregnant
- The risks and benefits of each medication you use when you are breastfeeding
What should I know about using medication to treat coronary heart disease during pregnancy?
A wide range of medications are given to CHD patients outside of pregnancy, including cholesterol-lowering drugs, aspirin, beta-blockers to slow the heart while increasing the power of each contraction, drugs to open blood vessels, and drugs to decrease blood pressure. However, the main medication issues for CHD during pregnancy relate to the fact that the treatment of choice is often to deliver the baby as early as possible and the fact that there is an increased risk of hemorrhage (severe bleeding), particularly if you are being treated with anticoagulation (blood thinning medication). The hormone oxytocin (Pitocin) is given to reduce the risk of hemorrhage, but it is also useful to induce labor. In women with CHD, it must be given very slowly to prevent a rapid drop in blood pressure. Some women with CHD require anticoagulation, the usual choice being low-molecular-weight heparin (LMWH). Generally, LMWH is used for short-term therapy, but once you are out of immediate danger, depending on your risk, doctors may wish to add a long-term anticoagulation treatment. The usual long-term treatment, called warfarin, is not a good option in pregnancy because it can reach and harm the developing baby, can be added after the baby is delivered.
Who should NOT stop taking medication for coronary heart disease in pregnancy?
CHD is a serious condition that complicates pregnancy if you are Class III or IV, and so any medications that are given are critical and withdrawing them poses more risk to the baby than continuing them. CHD is a situation in which taking the medication is a matter of life and death, so you MUST take the medication until it is ended by order of your physician.
What should I know about choosing a medication for coronary heart disease in pregnancy?
You may find Pregistrys expert reports about individual medications to treat coronary heart disease here. Additional information can also be found in the sources listed at the end of this report.
What should I know about taking a medication for coronary heart disease when I am breastfeeding?
Neither warfarin (used in North America for long-term anticoagulation therapy), nor a similar drug called acenocoumarol (used in Europe) enter breastmilk or otherwise affect a nursing infant. LMWH does enter breast milk, but in very tiny amounts and is not harmful because it is degraded in the inf
ants digestive system (LMWH is not taken orally for this reason, but must be injected or infused).
What alternative therapies exist besides medications to treat coronary heart disease during pregnancy?
Women with mild CHD (Class I/II) can usually be allowed to continue the pregnancy to term. In many cases, women with Class III or IV disease will need to deliver the infant as early as possible by inducing labor, sometimes with devices that assist in pulling out the infant, so that the woman does not need to push, as pushing can cause instabilities in blood pressure. Usually, vaginal delivery is the first option, since pregnant patients with CHD carry a risk of hemorrhage and other complications connected with cesarean section. In very severe cases of CHD, sometimes therapeutic abortion is the only option that will allow the mother to survive.
What can I do for myself and my baby when I have coronary heart disease during pregnancy?
It is vital that you work in consultation with all of your physicians, including your specialist in high-risk pregnancies or maternal-fetal medicine, and your cardiologist. Use the medication that your doctors prescribe.
Resources for coronary heart disease during pregnancy:
For more information about coronary heart disease during pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or read the following articles:
- Mayo Clinic: Heart conditions and pregnancy: Know the risks
- UK National Health Service: Coronary Heart Disease and Pregnancy