Marfan syndrome and pregnancy

Marfan syndrome comes from a change in the fibrillin gene, which affects the strength of connective tissue throughout the body. The part that matters most in pregnancy is the aorta, the large artery leaving the heart. MedlinePlus states that pregnant women with Marfan syndrome must be monitored very closely because of the increased stress on the heart and aorta.

During pregnancy the volume of blood the heart pumps rises and hormones change the behaviour of blood vessel walls. For most people this is well tolerated. When the aortic wall is weakened or already enlarged, those same changes can raise the chance of the aorta widening further or, rarely, tearing. The Marfan Foundation lists four things that shape the level of risk: whether the heart valves leak, whether there is existing aortic disease, the current width of the aorta, and any earlier aortic surgery.

The most useful step is taken before pregnancy starts. The Marfan Foundation describes a pre-pregnancy assessment with a general health review, a cardiology appointment that includes an echocardiogram to measure the aorta, a visit with a specialist in high-risk pregnancy, and genetic counselling.

In the UK this normally begins with your GP or your regular Marfan cardiologist, who can refer to a joint cardiac and obstetric clinic where one exists locally. The aim is to answer three practical questions: is the aorta in a range where the team is comfortable, does it need treatment or a repair first, and which of your current medicines should change.

• Bring recent echocardiogram or MRI reports so the team can compare measurements over time.

• List every medicine, including over-the-counter products and supplements.

• Ask whether genetic testing of the family variant has been done, since that shapes the options for your baby.

• Mention any previous aortic surgery, valve problems, eye or spine surgery, which also affect planning.

People often ask for a single aortic measurement above which pregnancy is unsafe. The Marfan Foundation is candid that there is no clear distinction between those who can and cannot tolerate pregnancy. Two women with the same measurement may have different valve findings, family histories or rates of change, and the team weighs all of these together.

This is why many centres prefer a repeat scan that shows whether the aorta is stable, rather than a single reading. If the aorta is large, a preventive repair before pregnancy may be discussed, and some women decide after counselling that they would rather consider other routes to parenthood. That choice belongs to you, and a good clinic will present the facts without pressure either way.

The NHS describes two main groups of aorta-protecting tablets in Marfan syndrome: beta blockers, which slow the heart rate and reduce the pull on the aortic wall, and angiotensin receptor blockers such as losartan or irbesartan, which are an alternative. Because medicines that are fine outside pregnancy are not always suitable during it, the cardiologist and obstetrician agree the regimen together, ideally before conception and certainly as soon as a pregnancy is confirmed. Do not stop or swap a tablet on your own, since coming off aorta-protecting treatment suddenly is also a risk.

During pregnancy, extra echocardiograms are the usual way to follow the aorta, and the plan for blood pressure, labour and delivery is written in advance by the combined team. The Marfan Foundation also warns that fluoroquinolone antibiotics should be avoided in people with Marfan syndrome and related aortic conditions, so tell every clinician who prescribes for you about your diagnosis.

The NHS explains that Marfan syndrome is usually inherited in an autosomal dominant way, so a parent with the condition has a 50% chance of passing it on with each pregnancy. About one case in four arises as a new change in an egg or sperm. The Marfan Foundation adds that if both parents were affected the chance rises to 75%, with the possibility of a more severe presentation.

Prenatal testing by chorionic villus sampling or amniocentesis can detect the family variant, according to the NHS, but the result does not predict how mild or severe the condition will be. Some families also explore testing of embryos during fertility treatment. A genetics service can explain which routes are available and how they are funded, and counselling is offered before and after any test.

The weeks after delivery are still a period of changing blood pressure and fluid shifts, so follow-up with the cardiology team continues rather than ending at the birth. Joint and spinal pain can also flare as ligaments recover, and the physiotherapy advice used for Marfan-related joint pain applies in the postnatal period too.

Sudden, severe chest, back or abdominal pain, especially described as tearing, or collapse, breathlessness or fainting, needs a 999 call at any stage of pregnancy or afterwards. Tell the ambulance crew and the emergency team that you have Marfan syndrome, because aortic dissection has to be considered promptly.