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Management Strategies
Preconception counseling/Contraceptive methods
Most women with repaired tetralogy of Fallot can have successful pregnancies. The risk of maternal cardiac complications depends on the severity of residual lesions at the time of conception. The most common complications are symptomatic right heart failure and arrhythmias. Maternal death is rare. (1,2,3,4,5,6,7,8,9)
A comprehensive cardiovascular examination should be undertaken before embarking on pregnancy. This includes a careful history and physical examination, an echocardiogram and an electrocardiogram, and may also include a cardiac magnetic resonance imaging study. The additional prognostic benefit of cardiopulmonary exercise testing has not been defined, but may be helpful in some cases.
Women with unrepaired tetralogy of Fallot suitable for surgical repair should be offered corrective surgery prior to embarking on pregnancy.
Transmission of congenital heart disease to offspring should be discussed. The risk of transmission of congenital heart disease is approximately 5-50%, compared to a background risk of 1% of having a baby with congenital heart disease. The risk of transmission is dependent on associated genetic syndrome. For instance, in women with microdeletions of chromosome 22q11, the risk of transmission to offspring is 50%. Genetic counseling is recommended for women with 22q11 deletion syndromes and for women with a family history of congenital heart disease or with other congenital defects.
A discussion about contraceptive methods is appropriate in all women with repaired or unrepaired tetralogy of Fallot. Combined hormonal contraceptives are contraindicated in women with unrepaired tetralogy of Fallot. (see Contraception)
Medication use should be reviewed if a woman is contemplating pregnancy or is pregnant. The MOTHERISK website is an excellent resource.
Ante-partum Care
Coordinated care between a congenital heart disease specialist and a high-risk obstetrician at a high-risk pregnancy center should be implemented. The frequency of follow-up visits is dictated by women’s functional status and the residual lesions at the time of conception.
Women with repaired tetralogy of Fallot and few or no residual lesions are at low to intermediate risk for complications. At the other end of the spectrum, women with significant residual lesions, ventricular dysfunction, or unrepaired tetralogy of Fallot require close follow by a dedicated multidisciplinary team of experienced cardiologists, high-risk obstetricians, and anesthetists.
All women should be offered fetal echocardiography at 20 weeks gestation.
Labour and Delivery
Labour and delivery should be planned carefully with a multidisciplinary team well in advance. It is important to communicate the delivery plan to the woman and to other physicians involved in her care. The best delivery plan is not useful if information is not readily available when needed.
Vaginal delivery is recommended in most instances. Good pain management for labour and delivery is very important in order to minimize maternal cardiac stress. To decrease maternal expulsive efforts during the second stage of labour, forceps or vacuum delivery is often utilized. To decrease potential harmful complications from difficult mid cavity-assisted delivery, uterine contractions are often utilized to facilitate the initial descent of the presenting part. In patients with unrepaired tetralogy of Fallot, oxytocic drugs such as oxytocin, which induces vasodilation and arterial hypotension, should be avoided.
The need for maternal monitoring is dictated by residual lesions and functional status of women. While cyanotic women with unrepaired tetralogy of Fallot may require invasive blood pressure monitoring, most women with repaired tetralogy of Fallot do not require special monitoring.
In general, endocarditis prophylaxis at the time of labour and delivery is not recommended in women with repaired tetralogy of Fallot. However, some experts continue to administer antibiotics because they feel that the risks of adverse reactions to antibiotics are small and the risk of developing endocarditis has major health consequences.
In patients with residual interatrial or interventricular shunts, air-particulate filters (bubble trap filters) are recommended for all intravenous lines.
Post-partum Care
The hemodynamic changes of pregnancy may take up to six months to normalize. Women should be seen early after pregnancy (usually within 6-8 weeks). The frequency of additional follow up visits should be dictated by the clinical status of the women.
