Heart disease in pregnancy: congenital and acquired conditions

During pregnancy the body's blood volume rises and the heart pumps more blood each minute, with further demands during labour and in the hours after delivery. A healthy heart copes easily. A heart with a narrowed valve, a weak pumping muscle, a rhythm problem or reduced blood supply may find the extra load difficult.

The NHS lists fluid on the lungs, heart failure, abnormal rhythms, slower growth of the baby because less oxygen and nutrition arrive, and premature birth as possible complications for women with congenital heart disease. How likely any of these are depends on the exact condition and how well the heart is working before conception.

Congenital heart disease means a structural difference present from birth, which may have been repaired in childhood. Acquired conditions include coronary heart disease, valve disease after rheumatic fever and cardiomyopathy. Some women learn about a heart condition for the first time during pregnancy because of breathlessness, palpitations or a murmur.

The NHS notes that risk factors for coronary disease include smoking, being overweight, diabetes, high blood pressure, high cholesterol, a family history of early heart disease and inactivity. Coronary disease in pregnancy is uncommon but becomes more relevant as women have children later in life.

A pre-conception visit lets the cardiologist describe how your condition may affect pregnancy and how pregnancy may affect your heart. The NHS says your specialist will review current medicines and what needs adjusting, and will give an individual picture because each case is different.

• Ask whether any medicines should be changed before you try, and do not make changes yourself.

• Ask for an up-to-date echocardiogram or other test if one has not been done recently.

• If you have a stent or previous heart surgery, ask how that affects antenatal care.

• Stopping smoking, reaching a healthier weight and building regular activity are all recommended before conception for those with coronary disease.

You can expect more appointments than in an uncomplicated pregnancy and a hospital-based maternity unit rather than a low-risk community setting. Cardiac review, ECGs and echocardiograms may be repeated as pregnancy progresses to see whether the heart is coping.

Pregnancy itself can occasionally cause heart problems. Peripartum cardiomyopathy, a weakening of the heart muscle in late pregnancy or soon after birth, is covered in a separate guide on this site.

The NHS says ACE inhibitors, used in heart failure, should not be taken in pregnancy and that any change to heart medicines should be agreed with a specialist. Low-dose aspirin is safe to continue in coronary disease. Some anticoagulants and rhythm drugs also need review, which is another reason for planning.

During pregnancy a balanced diet, staying as active as your team advises and not smoking all help. Talk to your midwife or GP before starting new exercise, and mention any change in how breathless you feel on ordinary activity.

The NHS advises hospital birth for women with coronary disease and says place of birth should be discussed with your team. For congenital heart disease the page explains that caesarean section is not automatic and that vaginal birth is generally preferred over induction when it is safe, sometimes with an epidural and assisted delivery to reduce straining.

The hours after delivery are a time of fluid shifts, so cardiac monitoring often continues into the postnatal ward. Plans for medicines while breastfeeding and for contraception should be agreed before discharge.

Call 999 for sudden chest pain that spreads to the arms, back, neck, jaw or tummy, particularly with sweating, nausea or breathlessness. For chest pain or breathlessness that comes and goes, the NHS advises an urgent GP appointment or a call to NHS 111, and in pregnancy you should also contact your maternity unit. Fainting, a racing heartbeat that does not settle, or breathlessness lying flat all need same-day assessment.