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Management Strategies
Preconception counseling/Contraceptive methods
The severity of MS and the functional status of the woman are important determinants of outcome during pregnancy. Women with a history of heart failure or arrhythmias are at higher risk for complications during pregnancy. Other cardiac characteristics can also have an impact on outcomes (see General Considerations)
Women with severe MS should be considered for intervention prior to pregnancy. When intervention is required, valvuloplasty is optimal in women of childbearing age. Indications for surgical or interventional procedures prior to pregnancy are based on current guidelines. (3)
A discussion about contraceptive methods is appropriate in women with MS. In general, most forms of contraception are safe in women with MS. However contraceptives containing estrogen should be used with caution, if at all, in women with atrial arrhythmias or prior thromboembolic events because of the associated thrombotic risk. (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 heart specialist and a high-risk obstetrician should be implemented at a high-risk pregnancy center. The frequency of follow-up visits and echocardiograms should be dictated by women’s functional status and the severity of her valve lesion.
Treatment for exercise intolerance or heart failure is necessary in some women. Heart rate control with a beta blocker is an important part of heart failure therapy, helping to prolong the diastolic filling time and allow effective atrial emptying and ventricular filling. (4) High doses of beta blockers may be needed as pregnancy progresses. Diuretic are added in women who remain symptomatic despite beta blocker therapy.
If atrial fibrillation develops during pregnancy, conversion to sinus rhythm is required. DC cardioversion is often used when women have rapid ventricular rates, are unstable or unresponsive to medical therapy. (see Arrhythmias)
Because of the stroke risk, anticoagulation is required for all women with atrial fibrillation (paroxysmal or persistent) or prior thromboembolic events.
Women with refractory cardiac symptoms during pregnancy may need to be considered for intervention. Initial therapy should include bed rest, treatment of aggravating factors such as anemia, and treatment of heart failure or arrhythmias. Valvuloplasty may be needed in women with refractory symptoms. Echocardiographic assessment of mitral valve anatomy and suitability for valvuloplasty is important. Compared to open mitral valve commissurotomy, percutaneous balloon mitral valvuloplasty is safer for the fetus/neonate. Valvuloplasty should only be performed by operators and in certers with expertise in the procedures. (5,6,7) Valvuloplasty during pregnancy exposes the fetus to radiation. Special attention should be given to minimizing radiation exposure in the fetus by shielding the gravid uterus and keeping fluoroscopy time to a minimum. However, the amount of radiation exposure is well within safety guidelines and radiation exposure is not a contraindication to a needed balloon mitral valvuloplasty. Echocardiographic guidance can reduce fetal exposure to ionizing radiation. Cardiopulmonary bypass surgery for mitral valve replacement during pregnancy carries a high risk of fetal loss and is only performed when women are refractory to therapy and valvuloplasty is not possible.
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.
Generally, vaginal delivery is recommended. Good pain management for labour and delivery is 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.
The need for maternal monitoring is dictated by the severity of MS and functional status of the women. Women with significant MS and atrial arrhythmias may require telemetry monitoring at the time of labour and delivery.
In general, endocarditis prophylaxis at the time of labour and delivery is not recommended in women with MS. 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.
Post-partum Care
The hemodynamic changes of pregnancy may take up to six months to fully normalize. Major adverse hemodynamic changes can occur in the first few post-partum days, and active therapy should be continued, under observation, for 72 hours, prior to hospital discharge. Women should be seen again early after pregnancy (usually within 6-8 weeks). The frequency of additional follow up visits should be dictated by the clinical status of the woman.
