Cardiovascular Diseases: What Are the Risks in Pregnancy?

During pregnancy and childbirth, a woman's body undergoes a series of physiological changes in her cardiovascular system. Those changes do not suppose any problem for most women, but women with cardiovascular disease or heart disease may have a high-risk pregnancy.

Heart disease, be it congenital or acquired, is the leading cause of maternal death of non-obstetric origin, so it is essential to see a doctor for advice when a woman wants to be a mother.

Some women with heart diseases have contraindicated pregnancy, so they will need to resort to techniques such as surrogacy to have a child without this presenting a risk to their health or that of the future baby.

Cardiovascular changes in pregnancy.

Pregnancy is a new state in a woman's body in which large metabolic changes occur in order to meet her needs and those of the growing fetus.

In order to meet this metabolic demand, the cardiovascular system undergoes a series of modifications caused by hormonal changes, the presence of uteroplacental circulation and the increase in the size of the uterus.

This adaptation of the female organism begins at a very early stage of pregnancy and becomes more and more noticeable as pregnancy progresses. In the following, we will detail the most important changes in the circulatory system during pregnancy:

• Increased blood volume
• Increased heart rate
• Increased cardiac output
• Decrease in peripheral resistances
• Decreased blood pressure

Cardiovascular changes in pregnancy

Maternal blood volume increases by 30-50% from the sixth week of gestation to meet the demand of the fetus. Maximum volume is reached in 20-24 weeks and is maintained until the baby is born.

As blood volume increases, a woman's heart needs to pump faster, so her heart rate goes from 10 to 15 beats per minute and, as a result, her heart rythm goes up by 30-40%.

On the other hand, the blood pressure decreases due to dilation of the blood vessels. This decrease is most striking in the second trimester and ceases to be so at the end of pregnancy. The heart also dilates and can increase in size up to 30%.

What are the risks?

Women with heart conditions who become pregnant may be at some risk depending on the severity and type of cardiovascular disease.

In general, due to the need to increase blood volume and cardiac output, compensated heart failure may occur. Thus, there is a higher incidence of fetal and neonatal complications in pregnant women with heart disease compared to the general population:

• Intrauterine growth restriction
• Fetal distress
• Intracranial hemorrhage
• Premature birth
• Perinatal mortality of 18%

The moments of special risk of cardiac decompensation correspond to the end of the first trimester (between 28 and 32 weeks of gestation), childbirth and the early puerperium (the first 10 days after delivery).

Complications of pregnancy from heart disease

In addition, women with a congenital heart defect have an increased risk that their baby will also be born with a heart defect.

Cardiovascular diseases

Despite all of the above, it must be kept in mind that most women with heart disease do not have serious problems carrying a pregnancy to term.

This usually depends on the type of heart disease and its severity, so each case should be evaluated by a cardiologist.

The World Health Organization (WHO) has established a classification of cardiovascular diseases according to the maternal risk they pose. These are discussed below:

Type I risk

These cardiovascular diseases are the mildest in relation to pregnancy, as they do not cause a detectable increased risk of maternal mortality or morbidity:

• Pulmonary stenosis
• Permeable ductus arteriosus
• Mitral valve prolapse
• Simple lesions repaired successfully
• Isolated atrial or ventricular extrasystoles

Type II risk

This group includes cardiovascular diseases that have a slightly increased risk of maternal mortality or moderate increase in morbidity:

• Unexplained atrial or ventricular septal defect
• Repair of tetralogy of Fallot
• Most of the arrhythmias

Type III risk

Here we find more serious cardiovascular diseases with an increased risk of maternal mortality or serious morbidity, so medical advice is required before attempting a pregnancy.

If the woman decides to become pregnant, intensive cardiac and obstetric monitoring throughout gestation, delivery and puerperium will be necessary.

These are the following cardiopathies or situations:

• Mechanical valve prosthesis
• Systemic right ventricle cases (atrial exchange, transposition of great vessels)
• Circulation of Fontan
• Unrepaired cyanotic heart disease
• Marfan syndrome with 40-45mm aortic dilation
• Aortic pathology associated with bicuspid aortic valve with aortic dilatation of 45-50mm
• Other complex congenital heart diseases, such as hypertrophic cardiomyopathy, congenital valvular heart disease, etc.

Type IV risk

These cardiovascular diseases have an extremely high risk of maternal mortality or serious morbidity, so pregnancy is completely contraindicated.

In the event that any of these women becomes pregnant, it would be advisable to assess a voluntary interruption of pregnancy or, if continued, to carry out strict monitoring.

Cardiovascular diseases associated with a high risk of complications during pregnancy are as follows:

• Pulmonary Hypertension
• Severe systemic ventricular dysfunction
• Previous peripartum cardiomyopathy with any residual impairment of the left ventricle
• Severe mitral stenosis
• Severe symptomatic aortic stenosis
• Marfan syndrome with >45mm aortic dilation
• Aortic pathology associated with bicuspid aortic valve with aortic dilatation of >50mm
• Coarctation of severe congenital aorta
• Eisenmenger syndrome

As we have said, women with this type of heart disease should be advised against pregnancy and even have an abortion if they are pregnant, as women with primary pulmonary hypertension and Eisenmenger syndrome, for example, have a 30 to 50% risk of mortality during pregnancy.

Therefore, many of these women choose to resort to surrogacy to become mothers before putting their lives at risk. It is considered that there is a medical incapacity to gestate and so must be indicated by the specialist in a medical certificate.

FAQs from users

What are the cardiovascular risk factors?

Cardiovascular risk factors, that is, those circumstances that are associated with a greater probability of suffering from cardiovascular disease can be divided into modifiable and non-modifiable factors.

Non-modifiable cardiovascular risk factors are those that cannot be changed, such as age, sex, and genetic inheritance. In general, males older than 40-45 have a higher risk of having a cardiovascular accident.

With regard to modifiable cardiovascular risk factors, we can highlight those related to lifestyle, such as obesity, cholesterol, tobacco, stress, etc.

Can I continue to take drugs for my cardiovascular disease in pregnancy?

Some medications have teratogenic effects for the fetus, so the medical specialist will have to assess the risk-benefit of each of the drugs for both the mother and the baby.

It will be necessary to adjust the dosage of the medicines or change them if there are other safer ones for gestation. However, it should be noted that in the event of a vital emergency, the mother will be given the drugs she requires.

What screening tests will I have during pregnancy if I have cardiovascular disease?

Women with some type of cardiac pathology will have to make more or less visits to the gynecologist and cardiologist during pregnancy depending on the severity of their illness.

At each prenatal visit, the woman's blood pressure and weight will be monitored. In addition, the following tests will be routine:

• Echocardiogram: This is a type of ultrasound in which the heart and its structures are observed.
• Electrocardiogram-This is used to record the electrical activity of the heart.

Suggested for you

In addition to cardiovascular diseases, there are other pathologies that also prevent women from becoming pregnant because they present a risk to their lives or that of the future baby. You can find out about it here: Medical Contraindications to Pregnancy – When to Use a Surrogate..

We talked about surrogacy as an alternative to having a child. If you want to know what it is and the countries to which you can travel to carry out the whole process, don't hesitate to read on here: What Is Surrogacy & How Does It Work? – Everything You Should Know.