Cardiac disease in pregnancy can be a challenge to manage as both the mother and baby are at risk. Even an uncomplicated normal pregnancy has many physiological changes which pose risk to cardiovascular system. Cardiac disease is a very common cause of maternal mortality in pregnancy.
Increase in cardiac output
Increase in plasma volume
Increased pulse rate
Labour – There is a sudden, increased cardiac output in second stage of labour due to auto transfusion of 300-500 ml of blood back in circulation and sympathetic stimulation by pain and anxiety. This is very dangerous for the mother and can make her prone to cardiac failure.
They can cause pulmonary edema at the time of delivery and post partum leading to cardiovascular compromise. This can be aggravated if excessive IV fluids are given or she has pre eclampsia.
Conditions where pregnancy is contraindicated
Marfan’s syndrome with dilated aortic root
Moderate to severe left ventricular outflow tract obstruction
LVEF < 0.3
Mortality in these conditions is nearly 50%. So termination should be advised.
Guidelines for management
Prosthetic heart valves– Anticoagulation has to be given. If patient is on warfarin, then we need to change to a safe drug as warfarin causes embryopathy. We need to shift to low molecular weight heparin or unfractionated heparin. Aspirin is also given. Patient has to be under multidisciplinary team of obstetrician, cardiologist, anaesthetist, intensivist and neonatologist.
Mitrial valve stenosis is very common congenital heart disease which can cause pulmonary oedema at time of delivery.
Peri partum cardiomyopathy is another dangerous condition defined as dilated cardiomyopathy with congestive heart failure in the last month of pregnancy or within 5 months of delivery. Treatment is similar to that of heart failure patients.
Monitoring for deterioration
Plan of delivery
Post partum surveillance
Preconceptional counselling by a multidisciplinary team
Plan of management of labour and delivery
Minimise cardiovascular load during delivery or post partum period
Drugs given are diuretics, digoxin, hydralazine, nitrates to decrease load on left ventricle
Mode of delivery- Vaginal delivery is preferred with effective pain relief with low dose regional analgesia. Cutting down the second stage by vacuum or forceps application is preferred to minimise load on heart.
Oxytocin should not be given as bolus but as slow infusion
Fluids should be given very slowly
Methergin should be avoided
Carboprost is not recommended
Post partum very intensive monitoring is done as patient can suddenly collapse due to sudden fluid changes. Infection should be quickly treated.
So to conclude we can say that pregnancy with heart disease is a serious condition and should be carefully seen by a team and with this approach, outcome can be favorable.