Haemodynamic changes in pregnancy
- Plasma volume increases by 30 - 50 % during pregnancy.
- Systemic vascular resistance reduces by 30 %.
- Oxygen consumption increases throughout the pregnancy.
- Haemodynamic changes persist for 2 - 3 weeks post delivery but may not completely resolve for upto 12 weeks.
- During labour and delivery cardiac output is further increased, especially after delivery of placenta, due to increased venous return from uterine contraction.
- It should be done by a cardiologist or obstetrician with an interest in heart disease in pregnancy.
- Counselling should include the effects of pregnancy on the mother and fetus as well.
- Predictors of adverse maternal events
NYHA class >II
Cyanosis ( SaO2 less than 90%
Prior Cardiovascular event
Systemic ventricular ejection fraction less than 40%
Left Heart Obstruction
Cyanosis ( SaO2 less than 90%
Prior Cardiovascular event
Systemic ventricular ejection fraction less than 40%
Left Heart Obstruction
Estimated risk of adverse event is 5 %, 27 % and 75 % with 0, 1 or > 1 of these risk factors respectively.
- There are some conditions that should be considered prohibitively high risk with a > 10 % risk of maternal death, and includes:
Pulmonary hypertension
Marfan syndrome with dilated aortic root ( risk reduced with surgical repair )
Severe left heart obstructive lesions ( risk reduced with repair ).
Systemic ventricular dysfunction
Marfan syndrome with dilated aortic root ( risk reduced with surgical repair )
Severe left heart obstructive lesions ( risk reduced with repair ).
Systemic ventricular dysfunction
Fetal Risk
MS, which is the most frequent VHD encountered during pregnancy, is often poorly tolerated when valve area is ,1.5 cm2, even in previously asymptomatic patients. Dyspnoea worsens between the third and fifth months, which corresponds to the increase in cardiac output. The persistence of dyspnoea or pulmonary hypertension is associated with a high risk of complications at delivery, thereby threatening the life of both the mother and foetus.
Severe AS is less frequently encountered during pregnancy. Complications occur mainly in patients who were symptomatic before pregnancy.225 The risk of heart failure during pregnancy or at delivery is low when mean aortic gradient is ,50 mmHg.
Foetal prognosis is also impaired in the case of stenotic heart valve disease, due to growth retardation, preterm delivery, and low birth weight. For these reasons, patients with severe MS or AS should be treated before pregnancy if possible, even in asymptomatic patients.
Chronic AR and MR are well tolerated during pregnancy, even when severe, provided LV systolic function is preserved.However, the risk of complications is high when LVEF is ,40%, the prognosis being close to that of cardiomyopathy. Conversely, acute regurgitation is poorly tolerated.
In patients with Marfan’s syndrome, the risk of aortic-related complications including dissection during pregnancy increases markedly when AR is more than mild or when maximum aortic diameter is .40 mm. In these cases, pregnancy should be preceded by replacement of the ascending aorta, in particular, when the native aortic valve can be preserved. Aortic complications should be considered in any patient presenting with chest pain or pain in the posterior thorax.
When the first visit occurs during pregnancy, early termination may be considered in the following situations:
- In general, drugs known to be teratogenic should be stopped preconception or once pregnancy is confirmed.
ACEI
Angiotensin II receptor antagonists
Amiodarone
Warfarin
Spironolactone
Angiotensin II receptor antagonists
Amiodarone
Warfarin
Spironolactone
MS, which is the most frequent VHD encountered during pregnancy, is often poorly tolerated when valve area is ,1.5 cm2, even in previously asymptomatic patients. Dyspnoea worsens between the third and fifth months, which corresponds to the increase in cardiac output. The persistence of dyspnoea or pulmonary hypertension is associated with a high risk of complications at delivery, thereby threatening the life of both the mother and foetus.
Severe AS is less frequently encountered during pregnancy. Complications occur mainly in patients who were symptomatic before pregnancy.225 The risk of heart failure during pregnancy or at delivery is low when mean aortic gradient is ,50 mmHg.
Foetal prognosis is also impaired in the case of stenotic heart valve disease, due to growth retardation, preterm delivery, and low birth weight. For these reasons, patients with severe MS or AS should be treated before pregnancy if possible, even in asymptomatic patients.
Chronic AR and MR are well tolerated during pregnancy, even when severe, provided LV systolic function is preserved.However, the risk of complications is high when LVEF is ,40%, the prognosis being close to that of cardiomyopathy. Conversely, acute regurgitation is poorly tolerated.
In patients with Marfan’s syndrome, the risk of aortic-related complications including dissection during pregnancy increases markedly when AR is more than mild or when maximum aortic diameter is .40 mm. In these cases, pregnancy should be preceded by replacement of the ascending aorta, in particular, when the native aortic valve can be preserved. Aortic complications should be considered in any patient presenting with chest pain or pain in the posterior thorax.
When the first visit occurs during pregnancy, early termination may be considered in the following situations:
- Severe LV dysfunction (EF ,40%).
- Marfan’s syndrome with aneurysm of ascending aorta 40 mm.
- Severe symptomatic stenotic valve disease, which cannot be treated using percutaneous procedures.
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