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Management Strategies
Preconception counseling/Contraceptive methods
Ideally, management for women with Marfan syndrome begins preconceptually. Risk of morbidity and mortality related to pregnancy should be reviewed with the prospective mother. Cardiac imaging should be arranged for detailed study of the aorta so that risk stratification can occur and should include echocardiography and optimally also cardiac magnetic resonance imaging (MRI) (note that the safety of the MRI during pregnancy has not been determined). MRI is preferred over cardiac computed tomography (CT) due to the ionizing radiation associated with the latter.
Despite thorough screening methods, ~ 10% of the genetic mutations that cause Marfan syndrome are still missed despite testing. Prenatal diagnosis can be accomplished by chorionic villus sampling or amniocentesis, and preimplantation diagnosis can be achieved through sampling a cell at the 8 cell blastocyst stage using techniques of in-vitro fertilization. Such testing is only useful, however, if the genetic abnormality in the affected parent has been previously determined.
Risk of pregnancy is relatively low in women with minimal cardiac involvement and an aortic root diameter < 40 mm, though pregnancy risk does exceed baseline risk in any woman with Marfan syndrome, even with an apparently normal aorta. As pregnancy is contraindicated in women with enlarged aortic roots, contraception should be used at least until more definitive management can be obtained.
A discussion about contraceptive methods is appropriate in all women with Marfan syndrome. Given evidence to suggest that there is a hormonally mediated decrease in aortic wall integrity (amount of mucopolysaccharides and loss of elastic fibres), estrogen-containing oral contraceptives should be avoided. (see Contraception)
In women with prior aortic valve replacement with a mechanical prosthesis, complexity and risk of anticoagulation during pregnancy should be highlighted antenatally. In any patients using anticoagulants, estrogen-containing contraceptive products are best avoided because they increase thrombosis risk.
Beta-blockers have been shown to slow growth of the aorta and decrease cardiovascular morbidity and mortality related to Marfan syndrome outside of pregnancy. By extension, they should therefore be used throughout pregnancy and for at least six months postpartum in patients not previously using them. It should be emphasized that many guidelines and expert recommendations call for universal use of beta blockers from the time the diagnosis of Marfan syndrome is made, independent of pregnancy. Risks and benefits should be discussed with the patient although there is a consensus that the ß1-selective agent, metoprolol, is well-tolerated by mother and fetus during pregnancy.
As certain cardiac medications and anticoagulants are contraindicated in pregnancy, medication use should be reviewed if a woman is contemplating pregnancy or is pregnant. The MOTHERISK website is an excellent resource.
Ante-partum Care
If a woman with Marfan syndrome is pregnant, care should be coordinated between a cardiologist and high-risk obstetrician.
Meticulous blood pressure control should be maintained throughout antenatal, perinatal, and postpartum periods to attenuate shear stress on the aorta.
Serial echocardiography should be performed at 6-8 week intervals during pregnancy and until the 6th post-partum month.
Beta-blockade should be maintained throughout pregnancy, as described above, and probably indefinitely thereafter.
If there is a need for ongoing anticoagulation, a hematologist should be involved to discuss risk and benefits of various strategies involving use of warfarin or low-molecular heparin throughout pregnancy.
Women may be offered fetal echocardiography at approximately 20 weeks gestation.
Labour and Delivery
Labour and delivery must be planned carefully with a multidisciplinary team well in advance of the proposed due date. The plan should be communicated to the patient and all potentially involved healthcare teams. Because a majority of patients with Marfan syndrome have lumbosacral dural ectasia, an anesthetist should be consulted well in advance of labour in order to assess the feasibility of early and continuous epidural anesthesia, the preferred method of analgesia during labour when it can be applied.
Planned Cesarean delivery rather than labour and vaginal delivery is advised if the aortic root exceeds a diameter of 40-45 mm, if there has been a history of previous dissection, or if there is evidence of progressive dilation of the aorta during pregnancy. This is one of the rare indications for cesarean delivery for cardiac reasons only. If vaginal delivery is planned, forceps or vacuum delivery is often utilized to decrease maternal expulsive efforts during the second stage of labour. 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.
Particular attention should be paid to avoidance of hypertension, which can be achieved with use of epidural anaesthesia and ß-blockers, with or without vasodilating agents.
In general, endocarditis prophylaxis at the time of labour and delivery is not recommended in women with Marfan syndrome. 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
Risk of aortic dilatation and dissection extends into the post-partum period. Pregnancy-related cardiovascular changes do not fully return to baseline until about 6 months post-partum. For this reason, follow up at a frequency thought to be appropriate by the coordinating physicians should take place until 6 months post-partum, and should include serial echocardiography.
Beta-blocking agents are excreted in breast mild, but can be used in nursing mothers when required.
