Many women with congenital heart disease have healthy pregnancies. Getting pregnant is not entirely risk-free, however, so it is important for the woman to talk to her pediatric and adult congenital cardiologist, obstetrician, and possibly other specialists like the fetal medicine perinatologist, and neonatologist ahead of time and explore any potential risks to herself and/or the baby.
Steps to take before getting pregnant
The key is to be properly evaluated before trying to get pregnant and to be in the best physical shape possible prior to trying to conceive. The preconception visit will involve assessing overall health, identifying any potential risk factors, and determining whether pregnancy is a viable option.
Those at high risk will need the support of a multi-disciplinary team. The pregnancy is also likely to be overseen by a high-risk obstetrician, often along with a cardiologist, throughout the pregnancy to watch for problems.
Other issues that will likely be discussed prior to pregnancy include the life expectancy of the mother and the risk of congenital heart disease recurrence in offspring. A genetic counselor can help determine risk and see whether there is a hereditary component to the congenital heart disease. A fetal echocardiogram will likely be recommended. This is also the time to discuss any concerns the woman may have about stress on the heart during pregnancy.
For males, there may be concerns about the ability to have a family and support it, so speaking to the cardiologist is helpful in order to get the right information and for a counseling referral if desired.
Risks associated with pregnancy
Overall, risk depends on the type of defect, the treatment received, and the physical condition of the mother (in terms of overall heart health). If treatment was very successful and no symptoms remain, risk is low. If there are still symptoms and a higher risk of complications, the overall risk is higher. The main concern with pregnancy is that it can worsen congenital heart disease symptoms, simply from the added pressure on the body, or cause symptoms where before there were none. The potential risks apply to both mother and child. Specifically, the demands on the mother's heart increase significantly during pregnancy and during delivery, affecting both the mother and the baby's health. Pregnant women with heart disease are at risk for maternal complications including heart failure, arrhythmia, and stroke. The mother's heart may not return to normal for as long as 6 months after delivery. Another issue is the use of drugs during pregnancy. Some drugs taken to manage heart symptoms can be harmful to a fetus. In some cases, and depending on the treatment that was provided for a condition, miscarriages may be more common.
These women are also at increased risk of neonatal complications (particularly if their risk is higher for non-cardiac complications), such as premature birth, low weight for age, fetal or newborn death, and respiratory distress. Women with cyanotic conditions are even more likely to have babies born prematurely, who weigh less than they should, who fail to thrive, and who face a higher risk of death. In addition, spontaneous abortion is more common.
Measuring risk
Patients with congenital heart disease are classified according to low, intermediate, and high-risk as follows:
| Low risk | Left-to-right shunts Repaired lesions without residual cardiac dysfunction Bicuspid aortic valve without stenosis Mild-moderate pulmonic stenosis Valvular regurgitation with normal ventricular systolic function |
| Intermediate risk | Unrepaired or palliated cyanotic CHD Uncorrected coarctation of the aorta Aortic stenosis Mechanical prosthetic valves Severe pulmonic stenosis Moderate to severe systemic ventricular dysfunction Symptomatic arrhythmia |
| High risk | NYHA functional class III or IV Significant pulmonary hypertension with or without right-to-left shunt Marfan syndrome with aortic root or major valvular involvement Severe aortic stenosis |
Source: J.M. Colman, S.C. Siu, Progress in Pediatric Cardiology 17 (2003), 53-60.
Functional ability is then classified according to the New York Heart Association (NYHA) Functional Classification (I through IV, with IV being at the poor end of the scale), as follows:
| Class | Definition |
|---|---|
I | No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, or dyspnea. |
II | Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, or dyspnea. |
III | Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, or dyspnea. |
III | Unable to carry on any physical activity without symptoms. Symptoms are present even at rest. If any physical activity is undertaken, symptoms are increased. |
Women with cyanotic heart conditions are at most risk of having a difficult pregnancy, with problems such as congestive heart failure. Women with obstructive defects are also more likely to develop hypertension during pregnancy. Also at risk are women with certain symptoms like arrhythmia, heart failure, or pulmonary hypertension.
High-risk pregnancy not advisable
Women with Eisenmenger syndrome, pulmonary vascular obstructive disease, and Marfan syndrome with involvement of the aorta are advised not to get pregnant. Up to 50% of women with Eisenmenger syndrome do not survive pregnancy.
Minimize risk in pregnancy
Women should be thoroughly evaluated before they attempt pregnancy. The doctor can then evaluate the individual's risk and do whatever can be done to minimize risk. Sometimes surgery is undertaken prior to conception to alleviate cyanosis or correct other lesions prior to pregnancy when the risk would increase
The doctor will also want to review the drug regimen (some drugs can harm a fetus), making sure the mother has been immunized and is not drinking alcohol, smoking, or taking recreational drugs.
During pregnancy, heart drugs may need to be switched, adjusted, or discontinued (e.g. warfarin is typically stopped prior to becoming pregnant). Conditions that develop during pregnancy (e.g. infection, high blood pressure, anemia) must be treated very aggressively. Also, in some cases, activity restriction or bed rest may be recommended.
There are some tests that the cardiologist can do to see if pregnancy might put too much pressure on the heart.
Problems the obstetrician may look for
The obstetrician will want to know if a woman with congenital heart disease is short of breath, what exercise is tolerated, if palpitations are being experienced, and the impression of the overall effect of the pregnancy on the body. The obstetrician will monitor pulse rate, rhythm, and blood pressure, and check for fluid pooling in the ankles and the lungs (edema). The doctor will also check for heart murmurs that might signal a worsening heart condition or infection. Along with all this, of course, the obstetrician will track the growth of the baby to make sure it is reaching the necessary milestones.
Ensure a healthy pregnancy
The following are general recommendations to help ensure a healthy pregnancy. They apply to all women, not just those with a CHD.
- Eat a balanced diet.
- Do not drink alcohol or take drugs.
- Do not smoke.
- Exercise prudently but regularly.
- Take folic acid daily and a multi-vitamin to ensure good nutrition and to protect against birth defects. If there is a family history of certain defects, including congenital heart defects, the doctor may suggest taking more than the standard recommended daily dose of folic acid (0.4 mg).
- Gain an appropriate amount of weight. (In fact, being at your ideal weight prior to conception helps to ensure optimal health for mum and baby.) A recent study has indicated that being overweight prior to pregnancy increases the risk of heart defects in the baby. This may have something to do with the fact that overweight women may be more vitamin deficient than the average woman. Being overweight can also lead to gestational diabetes, which has been linked with heart conditions and other problems. Most women need an extra 300 calories a day in their second and third trimesters.
- Get enough protein (60g), calcium (1000 mg), and iron (27 mg)
- Do not over-do it on the vitamin A, since this can also contribute to birth defects. (The same also goes for excessive folic acid).
- Avoid exposure to chemicals and toxic substances like pesticides, lead, and X-rays.
- Avoid exposure to sources of potential infection, like undercooked eggs and meat, as well as cat feces, which can cause a very serious condition called toxoplasmosis, which can be potentially fatal to the fetus.
Does heart disease affect delivery?
Generally, no. As with any other type of birth, Caesarean section (C-section) is necessary only when complications arise or potentially if a woman is considered to be very high risk in terms of her CHD. A vaginal birth is the expectation.
Special considerations after the birth
Sometimes women with congenital heart disease, depending on their condition, need to stay a bit longer in hospital after the birth. This provides time for their heart to adjust. Some may also need drugs to prevent blood clots in the legs, which are more common after birth. The doctor will want to do a check-up shortly after the birth to check the heart and the mother's overall condition.
For new mothers, it is important that they look after not just the baby, but themselves, watching in particular for any symptoms that need to be checked out. It takes time to get used to a new life with baby and they shouldn’t over-exert or expect too much of themselves all at once. Enlisting help from family and friends whenever possible is a good idea.
Will the baby have a heart defect too?
It is natural to want to jump ahead and wonder about future generations and whether they might be affected by congenital heart disease. At this point, it is known that there is an increased risk of transmission, and it seems more likely to be passed on through the mother rather than the father.
In terms of risk, numbers range from 3% to 5% although they may be higher in some types of heart disease. Risks are higher for mothers with congenital heart disease than if the father has a congenital cardiac condition. The highest risk of transmission is seen in women with ventricular obstructions or defects on the left side of the heart.
It is clear that the risk varies depending on the congenital heart disease, as well as on whether both parents have a congenital heart disease and whether congenital heart disease runs in the family. So it is important that when pregnancy is being contemplated, that the couple speak to a genetic counsellor and that the mother be seen by a high-risk pregnancy obstetrician and a cardiologist experienced in this area.